Superflow 110

SuperFlow Flowbench110 Instructions Section 1.0 Flow-testing 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 13.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 SuperFlow 110 description What is a flow test? Adapting heads for testing Flow test preliminaries Performing a flow test Test data sheet sample Analyzing the test data Avoiding test errors Air Flow Through Engines HP & RPM & CIO & CFM Intake Port Area & Shape Valve Seats Valve Sizes Valve Lift & Flow Combustion Chambers Dynamic Flow Effects Inertia - Supercharge Effect Test Pressure Conversion Chart Suggested Additional References Troubleshooting Page 1 2 2 3 4 6 8 9 10 12 16 18 18 19 22 23 24 26 27 29 1.0 Flow-testing 1.1 Superflow 110 description The Superflow 110 is designed to measure the air-flow resistance of engine cylinder heads, intake manifolds, velocity stacks, and restrictor plates. For intake testing, air is drawn in through the cylinder head into the machine, through the air blower, and exits through the orifice plate at the top of the Superflow 110. For.exhaust testing, the path of the air-flow is reversed by a switch on the front control panel. HSl 1 PRESSURE M[HR flOW CONTROL I KNOB ORIFICE PLATE TEST HEAD __ BLOWER The test pressure meter (manometer) measures the pressure or vacuum at the base of the test cylinder. The test pressure is adjusted to a standard value, for instance 15.0 inches of water, by turning the flow control knob on the lower front panel. Separate knobs c o ~ t r o l either the intake or exhaust flow. The amount of flow is read from the inclined flow meter (manometer). The flow meter measures the pressure difference across the 5 flow orifices at the top of the Superflow 110. By selecting different combinations of orifices, the flow meter can be used in any of 9 different ranges to obtain high accuracy over a wide range of flows. The flow meter reads 0 to 100% of any flow range selected with the rubber stoppers. A separate test orifice with a .312" diameter and a 1.875" diameter hole is included for calibration of the flow tester. The machine requires 110 VAC, or 110 VDC electrical power and draws 15 amps. 2 1.2 What is a flow test? In its simplest form, flow testing consists of blowing or sucking air through a cylinder head at a constant pressure. Then the flow rate is measured at various valve lifts. A change can be made and the head re-tested. Greater air flow indicates an improvement. If the tests are made under the same conditions, no corrections for atmospheric conditions or machine variations are required. The results may be compared directly. At the other extreme, it is possible to adjust and correct for all variations so that test results may be compared to those of any other head, tested under any conditions on any other Superflow machine. Further calculations can be made to determine valve efficiency and various recommended port lengths and cam timing. The calculations are very cumbersome without a small,electronic calculator, preferably with a square root key. The calculations are not essential to simple flow testing. 1.3 Adapting heads for testing Cylinder heads are mounted onto the Superflow by means of cylinder adaptors. The adaptor consists of a tube 4" long with the same bore as the engine and a flange welded on each end. The lower flange is bolted to the flow tester and the upper flange is bolted or clamped to the test cylinder head. The flanges must be flat or gasketed to make an airtight seal. The adaptor tube may be 1/16" larger or smaller than the actual engine cylinder. In some cases it is convenient to make the upper flange of the adaptor about 20% wider than the test cylinder head so that the head will be supported when it i ~ offset for testing the end cylinders. A device must be attached to the cylinder head to open the valves to the various test positions. The usual method is to attach a threaded DQUnt to a rocker arm stud so that the end of a bolt contacts the end of the valve stem. As the bolt is rotated, it pushes open the valve. A 0 to 1" x .001 dial indicator may be mounted to the same fixture with its tip contacting the valve spring retainer to measure the amount of valve opening. The standard valve springs should be replaced with light springs for testing. See the photos in the Superflow brochure for various types of valve openers. On the intake side of the cylinder head, it is strongly recommended that a radiused entrance guide be installed to lead the air straight into the head. The guide should be about one port width in thickness and be generously radiused on the inside all the way down to the head. The intake manifold can also be used. The exhaust flow may exit directly from the head. 1.4 Flow test preliminaries All test data may be recorded on the standard Superflow form F-120 test data sheet, (see sample). Before beginning a test, record the head description, and measure the stem and valve diameters. The net valve area is the valve area minus the stem area in square inches. net valve area = .785 (D 2 - valve D2 ) stem Before installing the test adapter, install only the standard test orifice plate onto the Superflow. Install all the rubber stoppers in the orifice plate on top of the Superflow and set the direction knob to intake. Close the intake and exhaust flow control knobs lightly against their seats. Zero the vertical test pressure meter and level and zero the inclined flow meter. With only the small .312" diameter test orifice open, turn on the machine and slowly open the intake flow control until the test pressure reaches 10.0" of water. The flow meter should now read approximately 45% on the 10.0 cfm range (#1 orifice open on top). This indicates a flow of .45 x 10 cfm = 4.5 cfm. If flow is within 1 cfm of this reading, the machine is working properly. Now remove all the rubber stoppers from the top orifice plate (185 cfm range) and open both the .312" and the 1.875" diameter holes in the test orifice. Adjust the intake flow control again until the test pressure reads 10.0". Allow the machine to warm up for several minutes until the upper thermometer reads about 25 0 F higher than the lower thermometer. Multiply the flow meter reading times 185 cfm to obtain the !llt It will be 153.2 cfm under standard conditions. If the flow meter does not read 153.2 cfm, the flow readings will all have to be corrected by a correction factor. This factor is equal to: 153.2 1f. Test flow correction factor = ---- ---- test orifice flow This factor compensates for machine variations and all atmospheric conditions. Enter this information on the test data sheet. For best accuracy, this factor should be determined before each day's testing. It does not need to be re-determined before additional tests on the same day. Multiply the flow ranges on line C by the correction factor to obtain the corrected range, and enter these in line D on the data sheet. The flow ranges may be used for all tests made on the same day. * If Superflow will not draw 10" due to low line voltage, use 8" test Then: 137.0 Flow correction factor - test orifice flow 3 4 All tests should be performed at the same ratio of valve lift to valve diameter, or LID ratio. Then the flow efficiencies of any valves can be compared, regardless of size. Multiply the valve diameter by each of the six LID ratios to obtain the valve lift test points. Fill these in on lines A and B of the data sheet. Choose the proper ~ pressure for the intake valve diameter from the chart b,elow. It is generally most convenient to test the exhaust valve at the same test pressure. Fill the test pressure in on line 3 of the data sheet. Valve diameter 2.111 to 2.3 11 1. 6 11 to 2.05 11 less than 1.6 Test pressure 5 11 1011 15" This completes all the preliminary preparations. While they are very time consuming, they will insure that the test results are valid and repeatable. Most of the preliminaries will not be required for subsequent tests of the same head. 1.5 Performing a flow test Remove ,the test orifice plate from the machine and install the test head, cylinder adapter, and valve opener onto the flow tester for the actual flow tests. Set the dial indicator to read 0 with the valve closed. Install either the intake manifold or an air inlet guide on the intake port. Zero the vertical test pressure meter and zero and level the inclined flow meter. Close the intake and exhaust flow control valves lightly a g a ~ n s t their seats (do not force or they will be damaged). Place the rubber stoppers into orifices 5, 4, 3 and 2. Turn the mode selector switch to intake. Turn on the Superflow and adjust the intake flow control until the test pressure meter reads the test pressure you intend to use. Determine the leakage flow from the flowmeter and chart. Because only the #1 orifice is open, the flow meter reads 10 cfm at 100%. A reading of 47% would indicate a leakage flow of .47 x 10 cfm c 4.7 efm. Leakage will usually be from 1 to 10 cfm. If there is no leakage, the test pressure may rise to the top of the meter. This does not matter as long as the flow meter reads zero. The leakage will not affect the test provided that you correct for it in your results. Turn off the Superflow. Repeat this test before the exhaust tests. Enter the leakage on line 8 of the data sheet to be subtracted from the chart cfm. Open the valve in the head to a lift of .20 valve diameter. Remove all four rubber stoppers from the flow orifices and turn on the Superflow. Adjust the flow test pressure to 10.0" and allow the machine to warm up for 5 minutes. This step may be omitted if the Superflow has been warmed up previously. The flowmeter is designed with multiple ranges so that the flow can be measured very accurately. For greatest accuracy, use only the orifice ranges which give readings above 70% of the scale. If the reading exceeds 100%, switch to the next higher range shown on the flow chart by changing the combination of orifices open at the top of the Superflow. If you have previously determined the proper flow ranges, fill in line 5 and skip the next step. If not, open the valve to the first of the six lift points. To select the proper flow range, begin with the largest stopper and re-install the stoppers in the flow orifices until the flow meter reads above 70%. This is the proper number of orifices for this test pressure, head, and valve lift. Always use the same combination for future tests at this point. From the chart on the front of the machine, determine the full scale range value, then record the corresponding corrected flow range from line D on line 5. Re-adjust the test pressure to the recommended value and record the readings of the flowmeter and the temperature difference between the top and bottom thermometers onto the Superflow F-120 data sheet. Turn off the machine. Go to the next valve lift and repeat the above steps. (Each valve lift may require a different flowmeter range.) Continue this procedure until you have reached the maximum lift test point. To test the exhaust port, turn the mode selector switch to exhaust and close the intake flow control valve. Move the valve opener and dial indicator to the exhaust valve and repeat the above procedures. This completes the test. For intake manifold tests, remove the radiused :\'1let a1r guide and replace it with the intake manifold. Repeat the intake tests and compare the results to determine the effect of the inta"ke manifold. 5 TEST DATA SHEET Test Description: CII£//Y 1lEt1P, #-3917281, STOCk #2 PtJRT hi/Til fZ. 'I R. ItVLET GtJ/PE, €;X1I/ltlS T OPEN FI&JM 11£ 19/J. Intake valve dia •• area: /9.('d., 'ZB6 IAI.2 Exhaust valve die •• area do, 1,671.;y1. Tes tOper ator /y. WIL L / ,4/J?.5 Da te .s-.;.... _______ _ Test orifice flow at 10" test preasure: ISO. 7 efm Test flow correction factor: 153.2/ IS(}, 7 - ..&1. ..... .:;0 .... '1.....:1 ___ _ Valve lift/diameter (LID) .05 .10 .15 .20 .25 .30 A. Intll}l-e valvE' lift (in) .097 ./94- .291 .38B .Sl?z. B. Exhaust valve lift (in ./So .ZZ5" ,306 .375" .4:;-0 1. Test Number 1 2 3 4 5 6 7 8 9 10 11 12 2. Test port number 2.£ -"'" 215 - , 3. Test pressure (in.) /0 ...... 4. Valve lift (in.) .097 ·/94 ·#85 .58Z ,()7S ,ISo .Z2S ,300 .37S 5. Carr. flow range (c fm) 1a;.9 I-I?S 18.3 -ftJ.7 6tJ.o 85':S 8£5' 6. Flowmeter .aB .906 .t!8S- ,7.96 .793 .7/& 798 .8Sz. 7. Chart cfm (L6xLS) 6s'1l 97..1 117.3 119./ 1.!o.4 /6:.2 3Z.4- "17' 68. 'Z. 7l.8 8. Leakage cm .s /,0 . .-. 9. Test cfm (L7-L8) 96.&, 116.8 1Z9.6 IZ9.9 l5.l 31." -16.' (0.-1 b72- 71.8 10. Temp. difference co .tIt/' SO· ..fo· .. . 4r& 4£" 4S" 4So 30 35 3S 11. Temp. diff. factor .917 .961! .966 .970 .973 /.az.. I.tJl7 1.0]'" /.aJ4 I.t7J4 (03'; 12. Carr. tes t c ftr.(J.llxL9) J!,l. 93. / II?€ 12""'7 I£' ". 3z.z 6l. z. 742- 13. Corr. cfm/in.2( L12) arel! /1. Z. 2,2.0 3Z.5 79." ".1--' -14.1.. 1!J.3 Z9.!J 37.4 4 Potential cfml in. 2 1 . (from Fi2.6.D.21) IS., Z7.3 -17.0 £7.1. 52..) 1j,6 Z7..J ¢/.o 5.,.., (;i). I 15. % flow rating <ill) f'z.. tl 79 8'f 1'7 71 70 68 71 71 fX#/'1v,sr /"UW /a? % ':' K /00%':: Sg7 Z Test Note8: ____ ___________________________________________________ __ Superflow Form F-120 . Q. . - - ca 'E .. .!2 .. .. .- ct - ca ;: c G) - & - c • u .. :. SAMPLE Test C!I£V Y HeAP SrDcI(.. #Z R:Rrdate 6:7- 7s- e Intake valve /. d. « db 'No A Exhaust valve /. so J. I I. 67 /N. -STaJ( ;; » • 1BO 140 120 100 . -.- . - j 1- -1 1 '. ! .• , .. _ _ _ .... ". l. - 'T-' .. - -- ; ,'·H- :. l_ _. i.. . ........ . ... _1 __ .. /. SO ..... (,/ .... ,--: .. , - - ---t ." . ----: : : -- __ . c .j ., ... . Co . - - tel Q) ... tel G) > - tel > - o o - .. < • • 8 1.7 Analyzing the test data For simple analysis of the test results, it is only necessary to calculate the test cfm, line 9. First calculate the chart cfm, line 7 by multiplying the flow meter reading, line 6, times line 5, the corrected flow range. Then subtract the leakage cfm, line 8, from line 7. The result is the !!!! cfm, line 9. This can be compared to other tests without further calculations. To correct for the temperature difference caused by the air passing through the blower motor, the test cfm must be multiplied by the temperature difference factor shown below. The temperature difference is the difference between the upper and lower thermometer readings. Temperature Difference Correction Factor Diff. 50 10 0 15 0 20 0 25 0 30 0 35 0 40 0 45 0 50 0 Intake .996 .992 .988 .984 .981 .977 .973 .970 .966 .962 55 0 .958 Exhaust 1.004 1.008 1.012 1.016 1.019 1.023 1.027 1.030 1.034 1.038 1.042 The result is line 12 the corrected test cfm. To obtain the valve . -- efficiency, it is necessary to calculate the flow in ~ per sguare inch of valve area and then compare that to the best yet achieved. Divide line 12 by the valve area in square inches to obtain line 13. Then fill in line 14 from the chart in section 7, figure 6. Divide line 13 by line 14 and multiply by 1 0 0 ~ to obtain line 15, the 1l ~ rating. The percent flow rating can be used as an indicator of the room left for futher improvements in flow. These results can also be plotted on the graph printed on the back of each test data sheet (see sample). The arrows shown indicate the scale to which the data is plotted. Circles are used to indicate the intake test points and triangles for the exhaust test points. Many additional factors and relationships are discussed in sections 2.0 through 10.0 which follow. 1.8 Avoiding Test Errors Each test you make involves considerable effort on your part, but this effort can all be wasted if you allow undetected errors to creep into your test program. Always check the following points to reduce the chances of mistakes. 1. Always use the same orifice range at the same test point. 2. Keep the leakage CFM to a minimum by making a good seal on all surfaces, including the valves in the head. 3. If light valve springs are used, make sure the valves are not sucked open by the vacuum of the intake tests. 4. Always level and zero the meters before each test. 5. Always use a flow inlet guide on the intake side of the head and always use the same guide and cylinder adapter. 6. Try to conduct your tests when there are no frequent changes in line voltage. Voltage changes will not affect the accuracy of the Superflow, but they will cause it to surge and be unstable. 7. As nearly as possible, conduct all tests with same equipment, used in the same way and at the same temperature. 8. When in doubt, repeat the tests. If you don't get the same results, start over. 9 10 2.0 AIR FLOW THROUGH ENGINES The horsepower of an engine is directly proportional to the amount of air drawn into the cylinder and retained until ignition occurs. By reducing the air flow resistance of the intake and exhaust tract, cylinder filling is improved and engine horsepower is increased directly. The average airflow through each engine cylinder can be estimated as follows: Average airflow (cfm) - 1.6 x HP per cylinder The intake airflow rate for a single cylinder will be about 2.5 times the average airflow for the cylinder because the intake occurs during only 40% of the total cycle. For example, if a Chevrolet V-8 engine produces 440 HP, the HP per cylinder is 55 HP. Average Airflow - 1.6 x 55 HP .. 88 cfm Avg. Intake Rate = 2.5 x 88 cfm - 220 cfm Peak Intake Rate - 2.5 x 220 cfm .. 550 cfm When an engine is operating, the pressure drop across the cylinder head ranges from 0 up to about 145 inches of water at the 550 cfm flow rate. (This is equivalent to the test pressure reading on the Super flow. ) The average pressure drop is about 23 inches of water (or about 2" of mercury) at the 220 cfm flow rate. When testing with the Superflow, it is not important whether a test pressure of 5 or 10, or 15 inches of water is used, provided the same pressure is used for each subsequent test that will be compared to the original test. A head that measures 10% better at 5 inches of water test pressure will also measure 10% better at 10 or 23 or 145 inches of water. The exception to this rule is at lower valve lifts or through small, long passages. Then the test pressure must be kept above a certain minimum to insure that the flow remains turbulent and does not slow down and become laminar. The minimum recommended pressures are as follows: Minimum Valve Lift .050" .100" .200" .300" Minimum Test Pressure 15" water 8" water 5" water 3" water Conveniently, the bigger the opening, the lower the required minimum test pressure. Beginners in flow-testing are frequently confused by carburetor flow ratings. Presently in the U.S., most carburetors are rated in flow capacity at a test pressure of 20.4 inches of water (1.5 inches of mercury), An 850 cfm carburetor is one that passes 850 cfm of air at a test pressure of 20.4 inches of water. However, if you observe a manifold vacuum gauge on a racing engine at full throttle, you will see that it only reads about 0.5 inches of mercury (7.8 inches 11 of water). At a test pressure of 7.8 inches of water, the same carburetor would only pass 490 cfm of air. This is why carburetor ratings appear to be all out of proportion to engine requiraments. Large carburetors may be tested and compared on the Superflow, but only at a reduced test pressure. At a test pressure of 1" of water, the carburetor wi:l flow 22% of its rated capacity at 1.5 inches of mercury. For example, at 1" test pressure, a 660 cfm carb will flow .22 x 660 = 145 cfm. 2.0 AIR FLOW THROUGH ENGINES (Cont'd) The amount of power to be gained by improved air-flow depends on the engine's volumetric efficiency (the percent the cylinder is full). An engine with 60% volumetric efficiency can be improved more than an engine with 90% volumetric efficiency. --------------------------------r----- ENGINE YOLUMETRIC EFFICIENCY 3000 cooo 5000 6000 7000 RPM The volumetric efficiency of a gasoline engine can be estimated as follows: 1. Volumetric Efficiency E 5600 x HP x 100% RPM x eIn where eIn is the displacement of the engine in cubic inches. Be sure you use accurate HP figures. If the volumetric efficiency on an un-supercharged engine exceeds 130% the HP or RPM figures are probably in error. For an alcohol burning engine, the formula is: Volumetric Efficiency - 4750 x HP x 100% 2. RPM x ern 12 3 ,0 HP & RPM & CID & CFM HP, RPM, CID and engine air-flow capacity are all related in a definite fashion. With the wide spread use of accurate engine dynamometers and flow-benches, it has become possible to measure the air-flow potential of a racing engine and then to predict its maximum potential HP and the RPM at which the HP will peak. The effect of porting and manifold changes can be anticipated in advance and proper camming changes made to take full advantage of the differences. The total air-flow thru a gasoline engine determines its maximum HP. At peak power, a racing engine will use 1.67 cubic feet of air (cfm) per minute for each HP it develops. For example, a 100 HP engine will use 167 cfm. This will hold true for any four-cycle gasoline burning racing e n g ~ n e . Alcohol burning engines will use 1.47 cfm per HP developed. To increase the engine power output, either the air-flow capacity of the engine must be increased, or the air-fuel charge must be burned more effectively. Racers have tended to concentrate primarily on increasing the air-flow. To put more air thru an engine, the flow resistance of the carburetor, intake manifold and cylinder head must be reduced. This need has led to hundreds of after market carburetors, manifolds and ported out cylinder heads, all designed to get more air thru the engine. The flow-bench is a measurement device designed to measure the air-flow capacity of various engine components. Air is blown, or sucked, thru the intake system at a standard pressure, and then the air-flow capacity is measured. In this manner, different parts can be compared and the effect of changes can be quickly evaluated. These flow tests are conducted at a constant peak air velocity at the valve, usually between 100 and 400 feet per second. While the flow-benc air velocity is not varying as it does in an operating engine, experiments have shown that flow-bench tests actually simulate engine operation closely enough. This is why flow-benches have become a major development tool for engine manufacturers and racers alike. But what'is the" relationship between the capacity on the flow bench and the horsepower of the engine? Tests have shown that if the complete intake system air-flow is measured at maximum valve lift and at a test pressure of 10" of water, a well developed racing engine will produce the follOWing HP per cylinder: 3. - .43 x (cfm at 10" of water) I ~ p ::: Of course to reach this level, the engine must also have the maximum compression, the right cam, and a tuned exhaust system. In short, it must be a well-tuned racing engine. With this formula, a head-porter can see that if he improves the maximum flow thru the intake system by 1 cfm, the engine will gain .43 HP per cylinder. (The formula is only for gasoline 4-stroke engines without super-chargers). The intake system flow also determines the RPM at which the racing engine will develop peak HP: 4. I RPM ... 2000 CIT> x (cfm at 10" at water) I 13 where CID is the engine displacement in cubic inches per cylinder. For super-stock and engines which are not all-ont racing engines, peak power will occur at 10% higher RPM than formula 4 indicates, so use 2200 instead ot 2000. Now, let's tryout these formulas on an example. If you have a "220 HP" small-block 292 Chevy which runs in super-stock, what will be the maximum HP at what RPM? Tests show that at a test pressure of 10" of water, this intake system will flow 105 cfm of air. The CID per cylinder is one-eighth of 292 or 36.5 CID. The 2000 for HP ... .43 x 105 cfm .. or for all 8 HP 0;: 8 x 45.1 RPM for maximum powe r will racing engines): RPM ... 2200 ':r03 cylinders = 361. 2 be (2200 is x 105 cfm 45.1 HP for super-stocks, ... 6330 RPM So the engine has a maximum potentai1 of 361 HP at 6330 RPM. But remember, this is the maximum potential HP. The engine will only approach this if everything else is optimized. Now, let's try another example to show how changes in the intake system will effect the engine performance. For this example, we will use a small block Chevy 302, displacement 37.75 CID per cylinder. Intake Flow Power Stock, 2.02" valve 120 cfm 413 HP @ 6360 RPM Normal ported, 2.02" valve 143 cfm 492 HP @ 7570 RPM Best ported, 2.02" valve 160 cfm 550 HP @ 8470 RPM Westlake, 2 x valves 175 cfm 602 HP @ 9270 RPM 14 The "Normal ported" head is about the best that can normally be achieved, even with careful flow-bench testing. However, it is possible to improve the head up to the "best ported" level, though welding might be required. For the last two heads, the engines must be wound up to 8500 and 9300 RPM to take full advantage of the additional flow. This brings us to the need for another guideline. If the engine must hold together for more than a couple runs down the drag strip, the peak power should not be developed at a piston speed in excess of 3700 feet per minute. If a few runs down the strip are all you want, this limit may be raised to 4600 fpm, but the engine will need super internal parts to last even one" run. These rules can be reduced to a simple formula for the RPM for peak HP (remember, your shift points may be 1000 RPM or more above peak HP): 5. Safe peak power RPM - 6. I Maximum peak power RPM - 22.200 1n. stroke I 27,600 I in. stroke Returning now to the e ~ p l e of the 302 engine, a well ported head would be adequate for most road-race applications for the 302 because the peak power is already being developed at slightly more than the 3800 fpm piston speed. If the power peak was pushed to an even higher RPM, the engine would frequently fail to finish the race. To take full advantage of the extra breathing of the Westlake 4-valve head, the power peak would have to be at 9270 RPM (4630 fpm) and engine life would be short. Without super internal parts, it would probably not survive even one run down the drag strip. The shift point would be up around 10,500 RPM. A lot for any Chevy! Now, if we pull all the formulas together, it is possible to construct a graph for determining the maximum intake system flow required for a particular engine and application. From this graph, you can easily select the required flow for any engine and RPM. Remember that the CFM, CID and HP figures are for each cylinder, not the entire engine. To use the graph, determine the CID per cylinder of your engine and then you can read the RPM required for any particular HP and the CFM of flow capacity that will be required on the flow-bench at a 10" test pressure. 16 For an example, suppose you have a 427 CID V-8 engine which will hold together up to 7500 RPM. From the graph for 53.4 CID (1/8 of 427), the m a x ~ power per cylinder would be 85 HP if you can tmprove your intake system to 196 cfm on the flow bench at 10" of water test pressure. For all eight cylinders, the engine could produce 680 HP at 7500 RPM. Of course it'. not enough to stmply calculate the flow capacity required. The engine must achieve it, and so let's talk about how to improve the engine airflow, and how to judge the flow potential of any engine. 4.0 Intake Port Area and Shape For maxtmum flow, the ideal intake system would have a single carburetor per cylinder with a slide-plate throttle and a venturi equal to .85 times the intake valve diameter. Below the venturi, the carburetor bore should gradually open up to the size of intake valve at the intake manifold entrance and gradually taper down to about .85 times the intake valve diameter at a point about 1/2" below the valve seat. The optimum length for the port will be discussed in Section 9.0. In practice, this ideal is never achieved, but it does provide a guide-line for what an efficient port would be 1:f.ke. When porting out a cylinder head for maximum flow, keep the following points in mind. 1. Flow losses arise from changes in direction and decreases in velocity (port bends and expansions). 2. Port area should be between 651. to 1001. of valve area. 3. Remove material primarily from the outside of port bends, not the inside. This will improve flow by increasing the radius of the bend. . 4. Port length and surface finish are not important to flow. 5. The greatest flow loss tn the intake port is due to the expansion of the air out of the valve. This makes the area from 1/2" below the valve to 1/2" above the valve the most critical part of the port. 6. The valve seat shape has a substantial effect on the flow. If flow losses are caused by port expansions, not contractions, you may wonder why the port should be necked down below the valve seat. The reason is that the air must both turn 90 0 and expand as it flows out of the valve into the engine cylinder. "Humping" the port inward just below the seat allows the air to make the turn outward toward the valve edge more gradually, reducing the total flow loss. Unfortunately, many stock ports are too large in this area already. The chart below shows approximately ~ h e r e the flow losses occur in a stock Chevy head with a 1.94" diameter intake valve. Note that the flow losses are negligible in the straight part of the port where ~ t is easy to grind. Source of Flow Loss 1 Loss .1 Wall friction 41 * .2 Contraction at push-rod 2 .3 Bend at valve guide 11 .4- Expansion behind valve guide 4 .5 Expans ion, 25 0 12 .6 Expans ion, 30 0 19 .7 Bend to exit valve 17 .t:'. Expansion exiting valve 31 1001. * For sand-cast surface. Would be 31. for polished surface. 17 18 As manufactured, this head flows about of its potential for a wedge-combustion chamber head. "The best head porters are able to increase the flow to about of its potential with the aid of careful flow-testing. Further improvements are difficult without major surgery and welding. Grinding and enlarging the first in the Chevy port where it is easy to reach has very little effect. S.O Valve Seats The valve seat has three purposes: to seal the port, to cool the valve, and to guide the air thru the valve. Sealing and cooling are promoted by a fairly wide seat between .060" and .100". Maximum flow is frequently achieved with a narrower seat, usually around .030" wide. Multiple angle to fully radiused seats are essential for good air flow. A typical comgetition intake valve seat will consist of a 30 0 top cut .100" wide, a 45 seat .040" wide, and a 70 0 inside cut .1SO" wide. An exhaust valve will work well with a lSo top cut .060" wide, followed by a 4S o seat .060" wide, and a 7S o inside cut .100" wide. The O.D. of the valve should coincide with the outside of the 4S o seat. Flow-bench experimentation will frequently uncover a superior shape for any particular head. A three angle seat will out-flow a simple 4S o seat by up to 2S% at lower valve lifts. 6.0 Valve Sizes The total flow thru the engine is ultimately determined by the valve diameters. While well-designed smaller valves will out perform larger valves on occaSion, a geod, big valve will always out-flow a good, smaller valve. Valve size is limited by the diameter of the engine bore. For wedge-shaped combustion chambers, the practical intake valve diameter is .52 times the bore diameter. Hemi-heads permit intake valves up to .57 times the bore diameter due to the extra space available in the combustion chamber. Four-valve heads are best of all, but the engf.ne must operate at very high-speed to take advantage of the extra valve area. The present trend in racing engines is to keep the exhaust system flow to SO% or 901. of the intake system flow. This may be more than is necessary. Tests indicate that there is generally no power improvement as long as the exhaust flow is greater than 60% of the intake flow. This would dictate an exhaust valve diameter .77 to .80 times as large as the intake valve. 19 7.0 Val ve Lift and Flow The air-flow thru the engine is directly controlled by the valve lift. The farther the valve opens, the greater the flow, at least up to a point. In order to discuss a wide variety of valve sizes, it is helpful to speak in terms of the ratio of valve lift to valve diameter or lid ratio. Stock engines usually have a peak lift of 1/4 of the valve diameter, or .25 d. Racing engines open the valves to .30 d or even .35 d. The graph in figure 4 shows how flow varies with lift for a well- designed valve and port. Up to .15 d, the flow is controlled mostly by the valve and seat area, but at higher lifts the flow peaks over and finally is controlled by .the maximum capacity of the port. Wedge-chamber intakes have lower flow at full lift due to masking and bends, and are port-limited' at a 15% lower level. 70 60 so .40 c .- ~ .E 30 u 20 10 , I ~ ., IJ Fig. 4. Valve potential air flow at a test pressure of 10" of water IP ... tl'. ~ ' I ' •• ~ ~ . ~ . , IJ ~ , ~ .10 M-It lim ~ t '/ / .... ~ , v ~ ~ ~ .... ~ ~ ..", ~ ~ ' f " J ~ . r- -- .20 Valve lift 1 0 , t II lame er .... ~ ,M- .. .30 .. , .... ~ . r- - - .40 20 Figure 6 can be used as a guide for judging the performance of any valve. To get the flow rate cfm for a particular valve, simply multiply the cfm per square inch from the chart by the valve area minus the valve stem area. The flow rate you get is not the "expected" flow rate, but rather the maximum potential flow rate for a particular head at the test pressure. The maximum potential flow for some of the popular heads are shown in the comparison chart in figure 5 at 10" of water test pressure. These figures represent the maximum air-flow which can be expected under optimum conditions of port and valve seat design. Even well modified heads will generally only 80i. to 90i. of these figures. Fig. 5 Maximum Potential Air Flow Valve Lift/Valve Diameter Intake Valves .05 .10 .15 .20 .25 .30d cfm lU" test pressure VW 1200, 1.24" D. 15.3 30.8 46.2 53.0 56.6 5B.9 Norton 850, 1. 50" D. 25.4 50.9 76.5 102.4 109.2 112.5 Yamaha TX 650, 1.62" D. 26.9 54.1 81.2 10B.7 115. B 119.0 Chev. Small Block, 1. 72" D. 30.3 60.9 91.5 104.8 112.0 116.7 Chev. Small Block, 2.02" D. 42.3 84.9 127.6 146.3 156.2 162.7 Chev. Westlake, 2x1.5" D. 50.7 101.8 153.0 204.B 21B.4 225.0 Ford 302, 2.25" D. 52.8 106.0 159.2 182.6 195.0 203.1 Chrys ler Hemi, 2.25" D. 52.8 106.0 159.2 213.2 227.2 233.4 If the flow reaches a maximum value at a lift of about .30 d, you may wonder why some cams are designed to open the valve farther, even as high as .37 d. The answer is that in order to open the valve more quickly and longer at lower lifts, it is necessary to "over-shoot" the maxtmum head-flow point. The extra flow is gained on the flanks of the lift pattern, not at the peak. The head-flow figures shown in Fig. 4, 5 and 6 are for the cylinder head alone with just a radiused inlet guide on the inlet port. When the intake manifold is installed the total flow will drop off from to depending on the flow efficiency of the manifold. By measuring the flow at each valve lift with and without the intake manifold, it is possible to accurately measure the flow efficiency. Frequently, the intake manifold will have even more room fOf improvement than does the cylinder head. It is the total flow with the intake manifold installed which must be used in formulas 3 and 4 described on pages 12 and 13. Fig. 6 Valve flow potential at various test pressures For herni-intake and all exhaust valves Valve Lift/Diameter .05 .10 .15 Test Pressure cfm per sq. 3" 7.4 15.0 22.5 5" 9.6 19.3 29.0 8" 12.2 24.4 36.7 10" 13.6 27.3 41.0 15" 16.7 33.4 50.2 20" 19.2 38.6 58.0 25" 21. 5 43.2 64.9 28" 22.8 45.6 68.6 36" 25.8 51. 8 77 .8 For wedge intake valves Valve Lift/Diameter .05 .10 Test Pressure cfm 3" 7.4 15.0 5" 9.6 19.3 8" 12.2 24.4 10" 13.6 27.3 15" 16.7 33.4 20" 19.2 38.6 25" 21.5 43.2 28" 22.8 45.6 36" 25.8 51.8 2 Valve area = .785 (D\a1ve .15 per sq. 22.5 29.0 36.7 41.0 50.2 58.0 64.9 68.6 77.8 .20 inch valve 30.0 38.8 49 .• 1 54.9 67.2 77 .6 86.7 91. 8 104 .20 inch valve 25.7 33.2 42.0 47.0 57.5 66.4 74.2 78.5 89.0 .25 area 32.0 41.4 52.3 58.5 71.6 82.7 92.5 98.0 111 .25 area 27.5 35.5 45.0 50.2 61.5 71.1 79.5 84.0 95.3 From a flow stand-point a herni-shaped combustion chamber has a 21 .30 33.0 42.5 53.8 60.1 73.6 85.0 95.1 101 104 .30 28.6 37.0 46.8 52.3 64.0 74.0 82.6 87.4 99.2 clear advantage over the wedge. Until the valve lift reaches .15 valve diameter, there is little difference, but at higher lifts the hemivalve is usually less shrouded. In most designs, the hemi-port is also straighter -due to the valve angle. These two advantages add up to an average flow advantage of 16% at higher lifts, even with equal valve diameters. When you consider that a herni-combustion chamber also generally permits the intake valve to be 10% greater diameter than a wedge, it is easy to understand the success of the herni-head racing engine. 22 8.0 Combustion Chambers In most engines, it appears that the combustion chamber design was dictated by the choice of valve geometry. Perhaps it should be the other way around. Most combustion chambers just don't combust as well as they should. Hemi and pent-roof combustion chambers are generally the best with wedge chambers being 54 to 1 0 ~ worse. Most gasoline burning racing engines use a compression ratio of between 12 and 13.5 to 1. If the cylinder is completely filled, you would expect that the torque per cubic inch of engine displacement would be the same, regardless of engine design. It isn't, and the differences are mostly due to combustion chamber effectiveness. One way to judge a combustion chamber's performance is to measure the torque output per cubic inch of engine displacement. At the RPM of peak torque, a good combustion chamber will develop 1.25 to 1.30 foot- pounds of torque per CID. It may be possible to raise this as high as 1.5 foot-pounds per CID, though not without an outstanding combustion chamber design and ram-tuning. Most racing Detroit V-8's only reach 1.15 foot-pounds per CID. There is plenty of room for improvement. A second guide line for judging efficient burning is the required spark advance for maximum power. The more efficient combustion chambers have higher turbulence and require less spark advance. A turbulent combustion chamber substantially reduces the "ignition delay" time between when the spark fires and the charge begins to burn rapidly. For example, a smell-block Chevy with a normal combustion chamber shape might require 42 BTDC maximum spark advance (35°.ignition delay), while a highly turbulent combustion chamber might only require 33 0 BTDC advance (27 0 ignition delay). The more turbulent chamber will also burn more rapidly and ,produce up to 10% greater power from the same initial charge. Combustion chamber improvement is more of an art than a science and so trial and error methods are frequently the only choice. In general, strive for high turbulence and minimize the distance from the spark plug to the f ~ t h e ~ part .of the combustion chamber. At times combustion chamber burning complexities can make it very confusing when trying to compare cylinder heads on an engine. For instance, it is difficult to compare a cylinder head on a Chevy 302 and then on a Chevy 330. While the same head will bolt onto both engines, the compression ratio, and combustion chamber effectiveness, and RPM range will all change. Even the degree of turbulence will change. These factors can mask differences due to the flow capacity of the heads and confound even the experienced engine builder. 23 9.0 Dynamic flow effects Engine volumetric efficiency and power can be increased considerably by taking advantage of the natural dynamic effects which occur during the intake cycle. Both the kinetic energy and the resonant pulses can be harnessed to fill the engine cylinder at volumetric efficiences up to 130%. Without these dynamic effects, volumetric efficiency is limited to 100% without supercharging. When the inlet valve closes, a pressure pulse bounces back out the intake tract, and then in again toward the valve. By making the intake tract the proper length, the returning pulse can be timed to arrive at top de.ad center of the next intake cycle, shoving extra air in and keeping exhaust gases out of the intake port. To visualize what occurs, imagine that one end of a steel bar is placed against a hard surface. If the other end is struck with a hammer, a strong pulse (the hammer blow) will travel down the bar to the other end, and then back to the hammer end. The pulse will actually cause the bar to jump back towards the hammer! While the bar (or the air in the port) moves very little, a strong pulse has been transmitted through it. To use this pulse, the intake port must be the correct length. The pulse will help only through a narrow range of RPM. Above or below a certain range the pulse will actually decrease power so proper synchronization is essential. There are actually several pulses which can be used, corresponding to the 2nd, 3rd and 4th time the pulse arrives at the valve. The 2nd pulse is best, the others being weaker and shorter. Fig. 7 Inlet pulsation chart Harmonic Length formula Lower RPM Upper RPM Pulse Strength* 2nd l32,000/RPM 89% 108% + 10% - 3rd 97,000/RPM 91% 104% + no 4 0 th 74,000/RPM 93% 104% + 4% - * Pulse strength varies with inlet flow and inlet valve opening The chart in Figure 7 shows the pulses which can be used. To obtain the inlet system length, divide the number shown by the RPM for peak HP as determined by the flow measurements (see Section 3.0). For example, at 8000 RPM for the 2nd harmonic: length - 132,000 8,000 a: 16.5" This is the desired length from the intake valve to the air inlet entrance. For engines with a plenum chamber type intake, the length is from the valve to the plenum chamber. The pulse in the example will benefit from 89% up to 108% of 8000 RPM, or from 7120 RPM up to 8640 RPM. The greatest benefit will occur at about 3% below 8000 RPM. Below 7120 RPM or above 8640 RPM, the "pulse will actually work to decrease engine power. 80 , 0 -.. • i 60 c - c;. ., ....... E - u 40 0 - "" - c( 20 24 To obtain benefits from the pulsation, it is also necessary that the intake valve be open to a lift of at least .02 times the valve diameter by 15 0 btdc. Openings of 20 0 to 40 0 btdc are usually preferable. The intake flow rating (see Section 10.0) must also be 0.3 or greater for significant benefits. 10.0 Inertia-supercharge effect When the intake valve starts to close, the fast moving air column tries to keep ramming itself into the cylinder. If the inlet valve is closed at just the right instant, the extra charge will be trapped in the cylinder (called inertia-supercharging). Volumetric efficiencies up to 1301 can be obtained. To determine the proper valve timing for maximum inertia-supercharge, it is necessary to determine the inertia supercharge index, Z,and then the valve closing timing can be determined from Figure 9. Z depends on the average inlet valve area, so this must be measured. First determine the inlet flow vs. valve lift for the complete intake system. Next determine the cam lift profile at the valve versus the degrees of engine rotation. From these two pieces of data A construct a graph, as shown in Figure 8, of engine flow in versus degrees of engine rotation. This is a plot of the total engine flow considering both the intake system and the cam • I - -.... .. -- - -- --. - . r- . :R: 1:-: :--1:-- _,1- -! -. ... -:- - - -' I .' •.. ,.1. , ... I I' ,. I .. \' I ; ", -.'. -,. :-+-I t -- "-':' ----:- I " .. ,. I .. i' I . . !. I ------ .;-... , --,.----+- - ... . - --I. ----- '-- •• I . ,. I - - -- -+ ... - .. ! I . I I " . , __ --- --------l ---- I I. -t- r --I -.-- - ,c I . , e . I -... -.. .,. ... --i --. I ' : . ! I . .. j . .., .; I - - .. - --- - ..... - - I I I . 1 I . J . . I . I I ' t:::c I;: _: ... : • i ; .. .. i .' ----r . , . : . - . I' .. : ... 1 .:. . I'" . . . t Fig. 8 Crank Angle Count the number of squares under the flow curve and divide them by the total number of squares beneath the 87 cfm line. The number obtained is the intake system flow rating Cv. - Area under flow curve Total area under 87 cfm line The C will generally be between 0.35 and 0.45 for good engines. This is a ¥otal rating of the intake system flow for any engine. The higher the Cv, the better the engine. The average inlet valve area is the Cv ttmes the intake valve area. 7. average inlet area E Cv x Valve area in sq. inches Now this data can be used to determine the inertia-supercharge index, Z, from the formula below: 8. RPM Z IC 126,000 CID x Inlet Length average inlet area where CID is the displacement of one cylinder in cubic inches and the inlet length is in inches. Z will usually be between 0.9 and 1.2, and is also a measure of the strength of the inertia-supercnarge which will be obtained. When Z has been determined, use Figure 9 to obtain the correct intake valve closing angle where the valve should be closed down to a lift of .10 x valve diameter. 25 l ' ! , ,. I - f - .--::--!--- i -_: - __ 1- I'; - t ., r l t j- - .- ---- ---'1'-'- -+- ---'1---;---- t---:----'--:--· .... .. -- -- . I • , - ,- - - I - I ' : . -'- TI '- I ------; I" '. I .- : ; --: -J .. i '-J . -I",: I " -: I - i , j . - .. I,! - - I 1.1 --:. i N; : - - -. j' . -. j: . - I :.. 1 I iIi - ! I j j, '''-1 -. . .,' -., -, ' t ., . I .. , I • I • . 'TT i -, , '. .. 1 • ... -; ...:..-..... :_._. ..... .9 1.3 1.2 1.0 • - -4- ___ , .. , .--,-. ' •• -+- .... - j., ... : 1 : : . L ____ . . i - ... j o 10 0 20 0 30 0 40 0 50 60 abc -+ .• '" •.. ..j- - .. -.. Fig. 9 Intake Valve Closing Angle at LID • .10 ... « ~ 0 - u. CII > 10 :I: 3" 5" 7" 10" 12" 15" 20" 25" 28" 30" 35" 40" 45 11 11.0 FLOW-8ENCH TEST PRESSURE CONVERSION CHART Want Flow At: 3" 5" 7" 10" 12" 15" 20" 25" 28" 30" 3S" 40" 45" 1.00 1.29 1.53 1.82 2.00 2.24 2.58 2.89 3.05 3.16 3.42 3.65 3.87 .774 1.00 1.18 1.41 1.55 1.73 2.00 2.24 2.37 2.45 2.65 2.83 3.00 .655 .845 1.00 1.12 1.31 1.46 1.69 1.89 2.00 2.07 2.24 2.39 2.54 .548 .707 .837 1.00 1.09 1.22 1.41 1.58 1.67 1.73 1.87 2.00 2.12 .SOO .64S .764 .913 1.00 1.12 1.29 1.44 1.53 1.58 1.71 1.83 1.94 .447 .577 .683 .816 .894 1.00 1.151.29 1.37 1.411.531.631.73 .387 .SOO .592 .707 .774 .866 1.00 1.12 1.18 1.22 1.32 1.41 1.50 .346 .447 .S29 .632 .693 .775 .894 1.00 1.06 1.10 1.18 1.26 1.34 .327 .422 • SOD .598 .654 .732 .845 .945 1.00 1.04 1 .12 1.20 1.27 .316 .408 .483 .577 .632 .707 .816 .913 .966 1.00 1.08 1.15 1.22 .293 .378 .447 .535 .586 .655 .756 .845 .894 .926 1.00 1.07 1.13 .274 .354 .418 .SOO .548 .612 .707 .791 .837 .866 .935 1.00 1.06 .258 .333 .394 .471 .516 .577 .667 .745 .789 .816 .882 .943 1.00 Example: If flow is 65 cfm at a test pressure of 5", what would flow be at 15"? cfm = 65 cfm x 1.73 = 112.5 cfm Test Pressure 1" H 2 0 3" 5" 8" 10" 12" 15" 20" 28" 30" 35" 40" 45" 65" FLOW RATE VS TEST PRESSURE Peak Velocity 66.2 fps 114.7 148.0 187.2 209.3 229.3 256.4 296.0 350.3 362.6 391.6 418.7 444.1 533.7 JfCFM/In 2 27.6 cfm 47.8 61.7 78.0 87.1 95.6 106.9 123.4 146.0 151 .1 163.3 174.6 185.1 222.5 *Flow thru a perfectly streamlined orifice with an area of I square inch. 26 12.0 Suggested Additional References Gas Flow in the Internal Combustion Engine Annand and Roe, 1974 (out of print.) Haessner Publishing Co. (Search Engineering Library) 27 The Internal Combustion Engine in Theory and Practice, Charles Fayette Taylor, 2nd edition, John Wiley & Sons, N.Y., NY. (Search Engineering Library) Internal Combustion Engines, Edward F. Obert, 2nd Edition, International Textbook Co., Scranton, PA. (Search Engineering Library) The Sports Car Engine, Colin Campbell Robert Bentley, Inc., (out of print, Public Library) The Theory and Practice of Cylinder Head Modification David Vizard, 1973, Classic Motorbooks, Osceola, WI, call (800) 826-6600 to order. Tuning BL's A-Series Engine David Vizard, 1985. Haynes Publishing Co., 861 Lawrence Drive, Newbury Park, CA 91320 (805) S.A.E. Technical Papers S.A.E. Technical Papers may be obtained by contacting Society of Automotive Engineers, INC. 400 Commonwealth Drive Warrendale, Pennsylvania 15096 (412) Request a Current Year Catalog or state by number and author and paper title listed below. Send along a fee of $3.50 for each paper requested. 700122* Research and Development of High-Speed, High- Performance, Small Displacement Honda Engines 1970 by S. Yagi 720214* Design Refinement of Induction and Exhaust Systems using Steady-State Flowbench Techniques 1972 by G.F. Leydorf, Jr. 790484* An Analysis of the Volumetric Efficiency Characteristics of 4 stroke Cycle Engines Using the Mean Inlet Mach Number. Feb. - March 1979 by Itaru Fukutani & Eiichi Watanabe 820154* AirFlow through Poppet Inlet Valves - Analysis of Static , Dynamic Flow Coefficients Feb. 1982 by Itauru Fukutani & Eiichi Watanabe 820410* A Study of Gas Exchange Process Simulation of an Automotive Multi-Cylinder Internal Combustion Engine Feb. 1982 by Masaaki Takizawa Tatsuo Uno , Toshiaki Oue Tadayoshi Yura Bosch Automotive Handbook from SAE Publications, $12.95. *All papers belonging to S.A.E. are covered by u.s. Copyright laws and cannot be reproduced without paying a fee or obtaining permission to reproduce from S.A.E. Publishing Division. SuperFlow reserves all rights for these instructions worldwide. Reproduction or translation of this work beyond that permitted by Sections 107 and 108 of the 1976 o.s. Copyright Act without permission of copyright owner is unlawful. Request for permission or further information should be addressed to SuperFlow Corporation. 28 4 ... , , I , I I I I , I , , I I ' l...J I I ~ r .. ··S' .. I I : 01 , I 1 f , I '" I -1- I I I , I r-/i-- I ' I '" : I I 1-•. 00 -1 Sac. .... EN r <SLVIt; ALL JOIN r" SCAAPE' ANP !¥1IVi"B .Au. E ~ 5 TOTAl MANUrACTIIII£ 'AIIT NO I DOC UGt:ND J 1 I II', J I -1 4 , I - - I -1 t-..L .. : I , 1'1 J I I 3 r, 1 I I I I , I I • 1 , , I l.. J I -rNiltu - it- MANUFACTUR[" ~ .. 1 ! 1 ANGU X:I:' a. CHECKE" MATUIAl eLlA" Ae:IJYLlC. NUT ASS[1IIt1tt. Y 2 "[LUS[ FOIl PROO OAT[ 3 - ''I - 7 ~ D C B A V-8 ADAPTEA, IDENTlneAT N MilE" SF - A ~ O O SCALE 1/:11. 1 TROUBLE SHOOTING YOUR FLOWBENCH When there seems to be a problem with the flowbench measuring system, do the following: 1) Unplug the brass/plastic tubing from manometer elbows, (4 places). 2) Unscrew elbows from the 3/4" nylon hex until they are flush with the top of the hex. Then, unscrew the 3/4" hex assembly until the elbows point toward the tubing. 3) Using spare plastic tubing puff or suck into each manometer elbow, making sure fluid responds and settles back to zero smoothly. Reconnect the tubing to the elbows. Turn flowbench back on. If problem still exists, please run the next three tests. The data you collect will be helpful in evaluating your problem. 1) NO FLOW TEST With SuperFlow's test orifice plate bolted on and all rubber stoppers tightly in holes, switch to intake mode. Turn machine on and place finger over small hole in test plate. Slowly, with both holes in test orifice plate plugged, adjust intake control valve until you reach 10" of test pressure on vertical manometer. Horizontal flow scale should rise slightly, then settle back to zero with machine running. If not, record reading. Repeat this test on exhaust. 2) LOW FLOW TEST Same test as above except remove finger from small hole and slowly open intake control valve until you reach 10" test pressure on vertical manometer. Record reading of horizontal manometer. Shut Intake Control Valve. Repeat test in exhaust mode:-- 3) HIGH FLOW TEST You should still be in the exhaust mode from the last test. Start by removing all rubber stoppers, top and bottom. Turn the machine-on and open the exhaust valve until you get 10" of test pressure on the vertical manometer. Record flow meter reading. NOTE: Sometimes the flowbench won't go to 10" of test pressure. In that case, adjust to 8" of test pressure and record the flow reading. Shut exhaust valve. Repeat test in Intake mode. ---- After recording the collected data, call SuperFlow, (303) 471-1746 and ask for flowbench customer service. Superflow 110 ~ CHECK-OUT INSTRUCTIONS 1. MACHINE PLACEMENT Remove the Superflow 110 from its shipping carton. Do not lift it by the plastic geges on the front panel. Place the Superflow 110 on e level table top. Turn the on - off switch to OFF and plug the Superflow in. 2. INSTRUMENT CONNECTIONS AND SET- UP A. To keep the fluid insids the manometers during shipping. the clear plastic tubes have been disconnected and the velves have been closed. Reed the instructions on the small red end white teg etteched to the flow meter. Open the plestic fluid velves on both metere [4 valvee.} B. Check the valves to make sure they are open by blowing gently Into each valve. using the extrs length of plastic tubing provided. If the fluid column moves end returns freely. the valve is open. Con- nect the four flexible plastic tubes onto the four meter Inlet tubes. C. A bubble level Is built Into the flow manometer. Level the n1I!lnometer by turning the screw near the left end of this manomater clockwise to loosen it. Reise or lower the left side of the manometer until the level bubble Is centered between the two merks. then re-tighten the screw. D. To zero the flow-percent scele. loosen the thumbscrew et the bottom of the flow menometsr end slide the scele to align the zero merk with the left end of the red fluid column. E. Zero the scele on the verticel test pressure manometer by rotating the knurled nut et the bottom of the scale. 3. OPERATION CHECK A. If you purchased a cylinder heed adapter, it is mounted to the flow bench baee plate on top of e flat test orifice plata. Remove the plastic adepter. B. Mount only the aix-inch aquare test orifice plate to the flow bench. Leave both the 1 7/8" and 5/16" holes in the test orifice open. but install the bolts and flat washers in ell four corners. C. Remove all rubber stoppers from orifice plete at the top of the flow bench. By referring to the flow chart. note thet this is the 185 cfm flow range. D. Set the mode selector switch to exhsust snd turn ~ ON the off-on switch. Close the inteke flow control valve gently ageinst its seat end opan ths exhaust flow control valve until the test pressure reeds 10.0" on the vertical meter. Observe the reading on the upper diegonal flow meter. The flow should be approximately 83% to 87% on the scale. If a test pressure of 8.0" i ~ used. the flow reading ehould be 74% to 78%. * Turn off the machine. E. Switch the mode control ewitch to intake and repaat the above etepa with the inteke flow control valve. The flow should be 78% to 82% on the scale. If a test pressure of 8.0" is used the flow should be 70% to 74%.* Turn off the machine. *Notice: The output of the SuperFlow 110 is proportional to the ~ i n e voltage at your location. At voltages below 120 VAC, or 240 VAC for foreign units, the SuperFlow maximum capacity will be less than normal. If the SuperFlow 110 will not reach 10 M of test pressure through the test orifice plate, perform the check-out tests (starting at OPERATION CHECK D-E) at 8 n of water test pressure. This does not have any effect on the accuracy. Power Requirements: SF-110 is 110 VAC or 110 VDC electrical power and draws 15 AMPS SF-II0E is 250 VAC or 250 VDC electrical power and draws 8 AMPS This completes the check-out test. If the SuperFlow 110 meets the above figures, it is ready for flow tests. Remove the test orfice plate and install the cylinder head adapter. If the SuperFlow 110 fails to meet the above standards, the unit may have been damaged in shippment. Please call the SuperFlow headquarters for further instructions. SuperFlow Corporation 3512 North Tejon Colorado Springs, Colorado, U.S.A. 80907 (303) 471-1746 eX.Customer Service 1.0 Flow-testing 1.1 Superflow 110 description The Superflow 110 is designed to measure the air-flow resistance of engine cylinder heads, intake manifolds, velocity stacks, and restrictor plates. For intake testing, air is drawn in through the cylinder head into the machine, through the air blower, and exits through the orifice plate at the top of the Superflow 110. For.exhaust testing, the path of the air-flow is reversed by a switch on the front control panel. ORIFICE PLATE PRESSURE HSl M[HR 1 flOW CONTROL KNOB TEST HEAD _ _ BLOWER I The test pressure meter (manometer) measures the pressure or vacuum at the base of the test cylinder. The test pressure is adjusted to a standard value, for instance 15.0 inches of water, by turning the flow control knob on the lower front panel. Separate knobs co~trol either the intake or exhaust flow. The amount of flow is read from the inclined flow meter (manometer). The flow meter measures the pressure difference across the 5 flow orifices at the top of the Superflow 110. By selecting different combinations of orifices, the flow meter can be used in any of 9 different ranges to obtain high accuracy over a wide range of flows. The flow meter reads 0 to 100% of any flow range selected with the rubber stoppers. A separate test orifice with a .312" diameter and a 1.875" diameter hole is included for calibration of the flow tester. The machine requires 110 VAC, or 110 VDC electrical power and draws 15 amps. 2 1.2 What is a flow test? In its simplest form, flow testing consists of blowing or sucking air through a cylinder head at a constant pressure. Then the flow rate is measured at various valve lifts. A change can be made and the head re-tested. Greater air flow indicates an improvement. If the tests are made under the same conditions, no corrections for atmospheric conditions or machine variations are required. The results may be compared directly. At the other extreme, it is possible to adjust and correct for all variations so that test results may be compared to those of any other head, tested under any conditions on any other Superflow machine. Further calculations can be made to determine valve efficiency and various recommended port lengths and cam timing. The calculations are very cumbersome without a small,electronic calculator, preferably with a square root key. The calculations are not essential to simple flow testing. 1.3 Adapting heads for testing Cylinder heads are mounted onto the Superflow by means of cylinder adaptors. The adaptor consists of a tube 4" long with the same bore as the engine and a flange welded on each end. The lower flange is bolted to the flow tester and the upper flange is bolted or clamped to the test cylinder head. The flanges must be flat or gasketed to make an airtight seal. The adaptor tube may be 1/16" larger or smaller than the actual engine cylinder. In some cases it is convenient to make the upper flange of the adaptor about 20% wider than the test cylinder head so that the head will be supported when it i~ offset for testing the end cylinders. A device must be attached to the cylinder head to open the valves to the various test positions. The usual method is to attach a threaded DQUnt to a rocker arm stud so that the end of a bolt contacts the end of the valve stem. As the bolt is rotated, it pushes open the valve. A 0 to 1" x .001 dial indicator may be mounted to the same fixture with its tip contacting the valve spring retainer to measure the amount of valve opening. The standard valve springs should be replaced with light springs for testing. See the photos in the Superflow brochure for various types of valve openers. On the intake side of the cylinder head, it is strongly recommended that a radiused entrance guide be installed to lead the air straight into the head. The guide should be about one port width in thickness and be generously radiused on the inside all the way down to the head. The intake manifold can also be used. The exhaust flow may exit directly from the head. The net valve area is the valve area minus the stem area in square inches. install only the standard test orifice plate onto the Superflow. Multiply the flow meter reading times 185 cfm to obtain the ! l l t orifice~. Enter this information on the test data sheet.---- = 153. Before beginning a test.312" and the 1.2 cfm under standard conditions.0". If flow is within 1 cfm of this reading.0" of water. this factor should be determined before each day's testing. use 8" test pressur~. the machine is working properly. and measure the stem and valve diameters. The co~rected flow ranges may be used for all tests made on the same day.2 1f. Multiply the flow ranges on line C by the correction factor to obtain the corrected range. It does not need to be re-determined before additional tests on the same day.2 cfm.0 cfm range (#1 orifice open on top). This indicates a flow of . turn on the machine and slowly open the intake flow control until the test pressure reaches 10. If the flow meter does not read 153. (see sample). Allow the machine to warm up for several minutes until the upper thermometer reads about 25 0 F higher than the lower thermometer. record the head description. With only the small . For best accuracy. Zero the vertical test pressure meter and level and zero the inclined flow meter.3 1. Install all the rubber stoppers in the orifice plate on top of the Superflow and set the direction knob to intake. This factor is equal to: Test flow correction factor ---.4 Flow test preliminaries All test data may be recorded on the standard Superflow form F-120 test data sheet. It will be 153. Adjust the intake flow control again until the test pressure reads 10. the flow readings will all have to be corrected by a correction factor. Then: 137. net valve area = .5 cfm. * If Superflow will not draw 10" due to low line voltage. and enter these in line D on the data sheet.0 Flow correction factor .45 x 10 cfm = 4.312" diameter test orifice open.test orifice flow . Now remove all the rubber stoppers from the top orifice plate (185 cfm range) and open both the . test orifice flow This factor compensates for machine variations and all atmospheric conditions.785 (D 2 valve D2 stem ) Before installing the test adapter. Close the intake and exhaust flow control knobs lightly against their seats. The flow meter should now read approximately 45% on the 10.875" diameter holes in the test orifice. 47 x 10 cfm c 4. Close the intake and exhaust flow control valves lightly aga~nst their seats (do not force or they will be damaged). 4. Place the rubber stoppers into orifices 5.05 11 less than 1. Fill the test pressure in on line 3 of the data sheet. Because only the #1 orifice is open.the test orifice plate from the machine and install the test head. Then the flow efficiencies of any valves can be compared. the test pressure may rise to the top of the meter. cylinder adapter. Zero the vertical test pressure meter and zero and level the inclined flow meter. Turn on the Superflow and adjust the intake flow control until the test pressure meter reads the test pressure you intend to use. It is generally most convenient to test the exhaust valve at the same test pressure. Open the valve in the head to a lift of . Enter the leakage on line 8 of the data sheet to be subtracted from the chart cfm. Choose the proper ~ pressure for the intake valve diameter from the chart b. Fill these in on lines A and B of the data sheet. While they are very time consuming. A reading of 47% would indicate a leakage flow of . they will insure that the test results are valid and repeatable. If there is no leakage.111 to 2.3 11 1. . Remove all four rubber stoppers from the flow orifices and turn on the Superflow. Set the dial indicator to read 0 with the valve closed. The leakage will not affect the test provided that you correct for it in your results. or LID ratio. 6 11 to 2. Determine the leakage flow from the flowmeter and chart. Install either the intake manifold or an air inlet guide on the intake port.elow. and valve opener onto the flow tester for the actual flow tests.20 valve diameter.0" and allow the machine to warm up for 5 minutes. Leakage will usually be from 1 to 10 cfm.4 All tests should be performed at the same ratio of valve lift to valve diameter. Most of the preliminaries will not be required for subsequent tests of the same head. Multiply the valve diameter by each of the six LID ratios to obtain the valve lift test points. 3 and 2. Turn off the Superflow.7 efm.6 Test pressure 511 1011 15" This completes all the preliminary preparations. the flow meter reads 10 cfm at 100%. Valve diameter 2. This step may be omitted if the Superflow has been warmed up previously. Adjust the flow test pressure to 10. 1. regardless of size. Repeat this test before the exhaust tests. This does not matter as long as the flow meter reads zero.5 Performing a flow test Remove . Turn the mode selector switch to intake. . begin with the largest stopper and re-install the stoppers in the flow orifices until the flow meter reads above 70%.) Continue this procedure until you have reached the maximum lift test point. switch to the next higher range shown on the flow chart by changing the combination of orifices open at the top of the Superflow. use only the orifice ranges which give readings above 70% of the scale. then record the corresponding corrected flow range from line D on line 5. From the chart on the front of the machine. turn the mode selector switch to exhaust and close the intake flow control valve. Repeat the intake tests and compare the results to determine the effect of the inta"ke manifold. and valve lift. This is the proper number of orifices for this test pressure. Go to the next valve lift and repeat the above steps. For greatest accuracy. head. Always use the same combination for future tests at this point. (Each valve lift may require a different flowmeter range. For intake manifold tests.5 The flowmeter is designed with multiple ranges so that the flow can be measured very accurately. fill in line 5 and skip the next step. This completes the test. determine the full scale range value. To select the proper flow range. If the reading exceeds 100%. If not. To test the exhaust port. open the valve to the first of the six lift points. Re-adjust the test pressure to the recommended value and record the readings of the flowmeter and the temperature difference between the top and bottom thermometers onto the Superflow F-120 data sheet. Turn off the machine. remove the radiused :\'1let a1r guide and replace it with the intake manifold. Move the valve opener and dial indicator to the exhaust valve and repeat the above procedures. If you have previously determined the proper flow ranges. -0 . Test pressure (in. Test Number 1 2 3 4 5 6 -"'" . Valve lift (in.ZZ5" .3 -ftJ. tes t c ftr.) 2....7 6tJ..8 ~5G 30 co ... Intll}l-e valvE' lift (in) .. diff..O 1~.(/'~ 18..~ 1~Z.30 .tIt/' SO· .O .0]'" /." -16.5 ·#85 .6. Leakage cm 9.05 A.l..37S 5. % flow rating Z.6 IZ9.097 B."17' /.961! .sr /"UW /a? % ':' :.llxL9) J!.0 £7.973 12.az.ISo . ..' (0.38B .. cfm/in. Exhaust valve die •• area l.1. .JC./94.(.Z2S .906 ..aJ4 I.-.()7S ..z ~l.. Temp.X1I/ltlS T STOCk #2 PtJRT hi/Til fZ.!o.Sl?z....-1 b72.J ¢/. Test cfm (L7-L8) 10.21) 15. factor .S .76~ . .0'1..0 68. 37.tJl7 I£' ".~ 6s'1l 97.y1. Da te ..097 ·/94 .20 .966 ." ~/. Test port number 3./ 1.2 Tes tOper ator /y.6. 6l.5 ISO. 'I R. . . (from Fi2.TEST DATA SHEET Test Description: CII£//Y 1lEt1P.. WIL L / . Corr..&.917 /1.£ /0 .:.4:.. _ Valve lift/diameter (LID) .) 4.2 3Z. Flowmeter I-I?S I.-.3 Z9.. 7. difference 33.3~-_7. 7 Test orifice flow at 10" test preasure: efm Test flow correction factor: 153.2 1 .~ 2..970 .~ K /00%':: Sg7 Z 71 Superflow Form F-120 .~I 215 . #-3917281.4 /6:.pO~T OPEN FI&JM 11£19/J.2( L12) arel! 4 Potential cfml in. Chart cfm (L6xLS) 8. Exhaust valve lift (in 07~ .s-. Carr.58Z . tl 79 8'f S~ ~8 71 70 71 Test Note8: ____~/N~~~~~~~n~ZD~~~_____________________________________________________ fX#/'1v. 52... 'Z...s J~O 6~tj 96..7. 7 .aB .4..306 .. 93..793 ....10 .o 85':S 8£5' 8S.~/O .3 -17. 7 8 9 10 11 12 2.(J.7/& '/~ 798 .t!8S. ~8.3 119.D. 'ZB6 IAI. / II?€ 12""'7 3Z. 13..9 l5.375" 1. z. 68 5~S" (. 3z.1. ItVLET GtJ/PE. I f'z.. Carr.~ .15 ... 1.~Z3 . .2/ IS(}.96 .. /~. .8 1Z9.5 79.1 117.~ ~.9 6. ...71.t7J4 (03'..4/J?. €.z...~I. I.25 ~£' .291 ..8Sz. 1!J.6 Z7.fo· 35 . flow range (c fm) -I~7 8~s 1a.) 1j.-1 /.5'o'~ do. Temp.0 ".2.671. 11.!J <ill) IS. 4r& 4£" 4S" 4So 1. 742#.1--' 1'7 -14._ _ _ _ _ _ __ Intake valve dia •• area: /9.:1 _ __ . . 3S .l 31.i). Z7.o 5.8 .~.4 6').~70 ../So . 7l..:.&1.. 116.('d...300 .~. .• .» I. 120 +----4----~----~--_+----~----~--~----+_--~'---~----+_--~ . .7sI A Exhaust valve /. -. tel > > G) o -a c ... ~ ". ~- . #Z R:Rrdate e Intake valve /... i. _...~----~---+----~----~--~----+_--~----_r----+_--~70 :.- 1- ~.. db 'No -:-~n:xJ(. SO =~I Co .." : : c .. 67/N.: :.....-. 'E ~ ~ . . .--: .~ -t. l_ _... . o ~ < .!2 ct ca 140 +----4--~... . .-.. ~ -1 1 '.~ ~.. ~ -STaJ( • ~I Q.. 9~ d.. 1BO . . ~ ·~'V (.~.~~-i. ./ . _1 __ ... ~. __ . ......'·H- 'T-' .B~ SrDcI(... . ----: . c G) .. -- ~ L~. . ... - -- .... « 6:7. .:. tel ~ Q) 100 tel .. /. so J. & • . l. _ ~_~ _ - !..~-!- ~ ~ - j ..~ c u • • . ...---t .j ..SAMPLE Test C!I£V Y HeAP #~/7Z. .034 1. Divide line 12 by the valve area in square inches to obtain line 13. Intake 50 .038 1.023 1. line 6.0 through 10.962 550 .7 Analyzing the test data For simple analysis of the test results. the 1l ~ rating. The result is the !!!! cfm. Many additional factors and relationships are discussed in sections 2. Divide line 13 by line 14 and multiply by 100~ to obtain line 15. These results can also be plotted on the graph printed on the back of each test data sheet (see sample). line 7 by multiplying the flow meter reading.008 1. line 8.027 1. the corrected flow range.. To correct for the temperature difference caused by the air passing through the blower motor.996 10 0 . figure 6.966 50 0 .970 Exhaust 1.030 1. the test cfm must be multiplied by the temperature difference factor shown below.977 .958 .992 15 0 20 0 . efficiency. . it is only necessary to calculate the test cfm. The percent flow rating can be used as an indicator of the room left for futher improvements in flow.012 1. Then subtract the leakage cfm. line 9. times line 5.To obtain the valve test cfm.988 . Then fill in line 14 from the chart in section 7.984 25 0 . First calculate the chart cfm. it is necessary to calculate the flow in ~ per sguare inch of valve area and then compare that to the best yet achieved.8 1.019 1.016 1.973 40 0 45 0 . This can be compared to other tests without further calculations.042 The result is line 12 the corrected . line 9. from line 7. The temperature difference is the difference between the upper and lower thermometer readings. Circles are used to indicate the intake test points and triangles for the exhaust test points. Temperature Difference Correction Factor Diff.004 1.0 which follow.981 30 0 350 . The arrows shown indicate the scale to which the data is plotted. Always use the same orifice range at the same test point.9 1. 5. When in doubt. used in the same way and at the same temperature. but this effort can all be wasted if you allow undetected errors to creep into your test program. 7. start over. make sure the valves are not sucked open by the vacuum of the intake tests. including the valves in the head. but they will cause it to surge and be unstable. 2. As nearly as possible. If you don't get the same results. . conduct all tests with same equipment. Voltage changes will not affect the accuracy of the Superflow. Always check the following points to reduce the chances of mistakes. 1. 4. Keep the leakage CFM to a minimum by making a good seal on all surfaces.8 Avoiding Test Errors Each test you make involves considerable effort on your part. 3. Always level and zero the meters before each test. Always use a flow inlet guide on the intake side of the head and always use the same guide and cylinder adapter. 6. 8. repeat the tests. If light valve springs are used. Try to conduct your tests when there are no frequent changes in line voltage. Then the test pressure must be kept above a certain minimum to insure that the flow remains turbulent and does not slow down and become laminar.5 x 220 cfm . ) The average pressure drop is about 23 inches of water (or about 2" of mercury) at the 220 cfm flow rate. The average airflow through each engine cylinder can be estimated as follows: Average airflow (cfm) .200" . The exception to this rule is at lower valve lifts or through small. When testing with the Superflow. For example. or 15 inches of water is used.300" Minimum Test Pressure 15" 8" 5" 3" water water water water Conveniently. the HP per cylinder is 55 HP. By reducing the air flow resistance of the intake and exhaust tract. provided the same pressure is used for each subsequent test that will be compared to the original test. the pressure drop across the cylinder head ranges from 0 up to about 145 inches of water at the 550 cfm flow rate. 88 cfm 2.5 times the average airflow for the cylinder because the intake occurs during only 40% of the total cycle. i f a Chevrolet V-8 engine produces 440 HP. .6 x 55 HP ..220 cfm 2.1. Average Airflow Avg. 550 cfm When an engine is operating. Intake Rate Peak Intake Rate = 1.0 AIR FLOW THROUGH ENGINES The horsepower of an engine is directly proportional to the amount of air drawn into the cylinder and retained until ignition occurs.5 x 88 cfm . it is not important whether a test pressure of 5 or 10. cylinder filling is improved and engine horsepower is increased directly. (This is equivalent to the test pressure reading on the Super flow. The minimum recommended pressures are as follows: Minimum Valve Lift . long passages.050" .100" . the lower the required minimum test pressure.10 2. A head that measures 10% better at 5 inches of water test pressure will also measure 10% better at 10 or 23 or 145 inches of water.6 x HP per cylinder The intake airflow rate for a single cylinder will be about 2.. the bigger the opening. the carburetor wi:l flow 22% of its rated capacity at 1.5 inches of mercury (7. At a test pressure of 7. If the volumetric efficiency on an un-supercharged engine exceeds 130% the HP or RPM figures are probably in error. An engine with 60% volumetric efficiency can be improved more than an engine with 90% volumetric efficiency. This is why carburetor ratings appear to be all out of proportion to engine requiraments.4750 x HP RPM x ern x 100% . a 660 cfm carb will flow . 1.5 inches of mercury.8 inches of water. you will see that it only reads about 0.22 x 660 = 145 cfm.8 inches of water). Volumetric Efficiency . --------------------------------r----- ENGINE YOLUMETRIC EFFICIENCY 3000 cooo 5000 6000 7000 RPM The volumetric efficiency of a gasoline engine can be estimated as follows: x 100% RPM x eIn where eIn is the displacement of the engine in cubic inches.5 inches of mercury).S.4 inches of water (1.11 Beginners in flow-testing are frequently confused by carburetor flow ratings. Volumetric Efficiency E 5600 x HP For an alcohol burning engine. An 850 cfm carburetor is one that passes 850 cfm of air at a test pressure of 20. Large carburetors may be tested and compared on the Superflow. 2. Presently in the U.0 AIR FLOW THROUGH ENGINES (Cont'd) The amount of power to be gained by improved air-flow depends on the engine's volumetric efficiency (the percent the cylinder is full). the formula is: 2. the same carburetor would only pass 490 cfm of air. but only at a reduced test pressure. Be sure you use accurate HP figures.4 inches of water. if you observe a manifold vacuum gauge on a racing engine at full throttle. at 1" test pressure. At a test pressure of 1" of water. However. For example. most carburetors are rated in flow capacity at a test pressure of 20.. or sucked. To put more air thru an engine.47 cfm per HP developed. The total air-flow thru a gasoline engine determines its maximum HP.43 x (cfm at 10" of water) I . manifolds and ported out cylinder heads. a well developed racing engine will produce the follOWing HP per cylinder: 3. experiments have shown that flow-bench tests actually simulate engine operation closely enough. the flow resistance of the carburetor. a 100 HP engine will use 167 cfm. The effect of porting and manifold changes can be anticipated in advance and proper camming changes made to take full advantage of the differences. different parts can be compared and the effect of changes can be quickly evaluated. This is why flow-benches have become a major development tool for engine manufacturers and racers alike.67 cubic feet of air (cfm) per minute for each HP it develops. With the wide spread use of accurate engine dynamometers and flow-benches.0 HP & RPM & CID & CFM HP. For example. ~p ::: . This will hold true for any four-cycle gasoline burning racing eng~ne. it has become possible to measure the air-flow potential of a racing engine and then to predict its maximum potential HP and the RPM at which the HP will peak. At peak power. all designed to get more air thru the engine. These flow tests are conducted at a constant peak air velocity at the valve. RPM. To increase the engine power output. This need has led to hundreds of after market carburetors. usually between 100 and 400 feet per second. a racing engine will use 1. or the air-fuel charge must be burned more effectively. The flow-bench is a measurement device designed to measure the air-flow capacity of various engine components. either the air-flow capacity of the engine must be increased. Air is blown. Racers have tended to concentrate primarily on increasing the air-flow. In this manner. and then the air-flow capacity is measured. intake manifold and cylinder head must be reduced.12 3 . thru the intake system at a standard pressure. Alcohol burning engines will use 1. CID and engine air-flow capacity are all related in a definite fashion. But what'is the" relationship between the capacity on the flow bench and the horsepower of the engine? Tests have shown that if the complete intake system air-flow is measured at maximum valve lift and at a test pressure of 10" of water. While the flow-benc air velocity is not varying as it does in an operating engine. I RPM . HP . 2 x 1. The intake system flow also determines the RPM at which the racing engine will develop peak HP: 4. this is the maximum potential HP.75 CID per cylinder. and a tuned exhaust system. so use 2200 instead ot 2000. this intake system will flow 105 cfm of air.43 HP per cylinder.13 Of course to reach this level. Now.1 = 361. (The formula is only for gasoline 4-stroke engines without super-chargers)... For this example. displacement 37. 2000 for racing engines): RPM . the engine must also have the maximum compression.1 or for all 8 cylinders HP 8 x 45.02" valve Best ported. 2. CIT> 2000 x (cfm at 10" at water) I where CID is the engine displacement in cubic inches per cylinder. 2 HP The RPM for maximum powe r will be (2200 is for super-stocks. For super-stock and engines which are not all-ont racing engines. 2.. But remember.. Now. If you have a "220 HP" small-block 292 Chevy which runs in super-stock. ':r03 2200 x 105 cfm . ~ Intake 120 143 160 175 S~stem Flow 413 492 550 602 Power HP HP HP HP @ @ @ @ Stock. we will use a small block Chevy 302. a head-porter can see that if he improves the maximum flow thru the intake system by 1 cfm.: . The engine will only approach this if everything else is optimized. what will be the maximum HP at what RPM? Tests show that at a test pressure of 10" of water. 2. With this formula...~' valves cfm cfm cfm cfm 6360 7570 8470 9270 RPM RPM RPM RPM . the right cam.. let's tryout these formulas on an example.5 CID. let's try another example to show how changes in the intake system will effect the engine performance.43 x 105 cfm . 0.02" valve Normal ported. 45. In short. 6330 RPM So the engine has a maximum potentai1 of 361 HP at 6330 RPM. it must be a well-tuned racing engine.02" valve Westlake. the engine will gain . peak power will occur at 10% higher RPM than formula 4 indicates. The CID per cylinder is one-eighth of 292 or 36.. 14 The "Normal ported" head is about the best that can normally be achieved. To take full advantage of the extra breathing of the Westlake 4-valve head. the power peak would have to be at 9270 RPM (4630 fpm) and engine life would be short.500 RPM. a well ported head would be adequate for most road-race applications for the 302 because the peak power is already being developed at slightly more than the 3800 fpm piston speed. A lot for any Chevy! Now. even with careful flow-bench testing. . If the engine must hold together for more than a couple runs down the drag strip. it would probably not survive even one run down the drag strip. From this graph. If a few runs down the strip are all you want. the peak power should not be developed at a piston speed in excess of 3700 feet per minute. For the last two heads. Remember that the CFM. To use the graph. this limit may be raised to 4600 fpm. it is possible to construct a graph for determining the maximum intake system flow required for a particular engine and application. but the engine will need super internal parts to last even one" run. stroke Returning now to the e~ple of the 302 engine. not the entire engine. though welding might be required. if we pull all the formulas together. the engine would frequently fail to finish the race. However. determine the CID per cylinder of your engine and then you can read the RPM required for any particular HP and the CFM of flow capacity that will be required on the flow-bench at a 10" test pressure. This brings us to the need for another guideline. Without super internal parts. your shift points may be 1000 RPM or more above peak HP): 5. Safe peak power RPM 22. stroke I I 6. CID and HP figures are for each cylinder. I Maximum peak power RPM - 27. These rules can be reduced to a simple formula for the RPM for peak HP (remember. If the power peak was pushed to an even higher RPM. the engines must be wound up to 8500 and 9300 RPM to take full advantage of the additional flow.600 in. you can easily select the required flow for any engine and RPM. it is possible to improve the head up to the "best ported" level.200 1n. The shift point would be up around 10. . For all eight cylinders. Below the venturi. Of course it'. From the graph for 53.16 For an example. The engine must achieve it. not enough to stmply calculate the flow capacity required. and so let's talk about how to improve the engine airflow.0 Intake Port Area and Shape For maxtmum flow.4 CID (1/8 of 427). and how to judge the flow potential of any engine.0. the carburetor bore should gradually open up to the size of intake valve at the intake manifold entrance and gradually taper down to about . The optimum length for the port will be discussed in Section 9. the max~ power per cylinder would be 85 HP if you can tmprove your intake system to 196 cfm on the flow bench at 10" of water test pressure. the engine could produce 680 HP at 7500 RPM. 4. suppose you have a 427 CID V-8 engine which will hold together up to 7500 RPM.85 times the intake valve diameter.85 times the intake valve diameter at a point about 1/2" below the valve seat. the ideal intake system would have a single carburetor per cylinder with a slide-plate throttle and a venturi equal to . . 17 In practice.5 Expans ion. The chart below shows approximately ~here the flow losses occur in a stock Chevy head with a 1. Flow losses arise from changes in direction and decreases in velocity (port bends and expansions). This makes the area from 1/2" below the valve to 1/2" above the valve the most critical part of the port. 250 0 .3 1 Loss 41 2 11 4 * Bend at valve guide Expansion behind valve guide . keep the following points in mind. The reason is that the air must both turn 90 0 and expand as it flows out of the valve into the engine cylinder. Unfortunately. If flow losses are caused by port expansions. Would be 31. 4.2 Contraction at push-rod . not contractions. When porting out a cylinder head for maximum flow. but it does provide a guide-line for what an efficient port would be 1:f. 2. you may wonder why the port should be necked down below the valve seat.t:'. 30 . to 1001.7 Bend to exit valve . not the inside. . * For sand-cast surface. The valve seat shape has a substantial effect on the flow. of valve area. "Humping" the port inward just below the seat allows the air to make the turn outward toward the valve edge more gradually.1 Wall friction . 6. Remove material primarily from the outside of port bends. This will improve flow by increasing the radius of the bend.6 Expans ion. this ideal is never achieved. many stock ports are too large in this area already. Note that the flow losses are negligible in the straight part of the port where ~t is easy to grind.94" diameter intake valve. Port length and surface finish are not important to flow. .ke. Expansion exiting valve . Source of Flow Loss . 5. The greatest flow loss tn the intake port is due to the expansion of the air out of the valve.4- 12 19 17 31 1001. 3. 1. reducing the total flow loss. for polished surface. Port area should be between 651. 6. Hemi-heads permit intake valves up to . and a 70 0 inside cut . this head flows about 83~ of its potential for a wedge-combustion chamber head. For wedge-shaped combustion chambers.040" wide. The O. Multiple angle to fully radiused seats are essential for good air flow. S.O Valve Seats The valve seat has three purposes: to seal the port. Four-valve heads are best of all. Maximum flow is frequently achieved with a narrower seat. An exhaust valve will work well with a lSo top cut . usually around . This may be more than is necessary. and to guide the air thru the valve. Flow-bench experimentation will frequently uncover a superior shape for any partio cular head. followed by a 4S o seat .ne must operate at very high-speed to take advantage of the extra valve area.060" and .030" wide. Further improvements are difficult without major surgery and welding.80 times as large as the intake valve. This would dictate an exhaust valve diameter . and a 7S o inside cut .57 times the bore diameter due to the extra space available in the combustion chamber.060" wide. . A three angle seat will out-flow a simple 4S seat by up to 2S% at lower valve lifts. smaller valve.77 to . Tests indicate that there is generally no power improvement as long as the exhaust flow is greater than 60% of the intake flow. a 45 seat . Grinding and enlarging the first 2~' in the Chevy port where it is easy to reach has very little effect.1SO" wide. Sealing and cooling are promoted by a fairly wide seat between . but the engf. Valve size is limited by the diameter of the engine bore. A typical comgetition intake valve seat will consist of a 30 0 top cut .18 As manufactured. The present trend in racing engines is to keep the exhaust system flow to SO% or 901.100" wide.100" wide.100". "The best head porters are able to increase the flow to about 9S~ of its potential with the aid of careful flow-testing. of the intake system flow.060" wide. While well-designed smaller valves will out perform larger valves on occaSion.D. a geod. to cool the valve. the practical max~um intake valve diameter is .52 times the bore diameter. big valve will always out-flow a good.0 Valve Sizes The total flow thru the engine is ultimately determined by the valve diameters. of the valve should coincide with the outside of the 4So seat. .40 .40 ... it is helpful to speak in terms of the ratio of valve lift to valve diameter or lid ratio. Racing engines open the valves to . ~ .10 .. Stock engines usually have a peak lift of 1/4 of the valve diameter. . r.19 7.. ~ ~ .the maximum capacity of the port. The graph in figure 4 shows how flow varies with lift for a welldesigned valve and port.E u 30 ~ .. ~ . Fig. the greater the flow.M- .35 d. •• ~'I' ~ IJ 20 ~ .. or . the flow is controlled mostly by the valve and seat area.- c. 4.. ~.0 Val ve Lift and Flow The air-flow thru the engine is directly controlled by the valve lift.20 Valve lift II0 lamet er 1 . ~ ~ . tl'.. at least up to a point.15 d. ~ . In order to discuss a wide variety of valve sizes.. Valve potential air flow at a test pressure of 10" of water 70 IP M. ~ J . 10 ..". . . Wedge-chamber intakes have lower flow at full lift due to masking and bends. and are port-limited' at a 15% lower level.It lim ~t / 60 '/ so ~'f" ~~ ~ v .~.30 . . but at higher lifts the flow peaks over and finally is controlled by .. . .30 d or even . IJ I~ r- -- . The farther the valve opens. Up to ...25 d. .....- .. 8 112.3 42.0 159.5 104.2 227. 4.4 26.20 .0 106. to 90i.2 182. 5 and 6 are for the cylinder head alone with just a radiused inlet guide on the inlet port.3 25.30 d. 2.0 127.25" D.5" D. not at the peak.20 Figure 6 can be used as a guide for judging the performance of any valve.2 213.15 . To get the flow rate cfm for a particular valve. 2. depending on the flow efficiency of the manifold.24" D.37 d.0 204. The flow rate you get is not the "expected" flow rate.0 159.02" D. Chev. 2x1.7 162.8 76. Frequently. the intake manifold will have even more room fOf improvement than does the cylinder head.3 156. .2 84. 2. 5 Maximum Potential Air Flow Valve Lift/Valve Diameter . it is possible to accurately measure the flow efficiency.8 52.9 91.30d Intake Valves VW 1200. Ford 302.62" D.9 30.6 195.2 53.8 5B.4 106.0 30. but rather the maximum potential flow rate for a particular head at the test pressure.7 115. even as high as . Small Block. simply multiply the cfm per square inch from the chart by the valve area minus the valve stem area.0 116.4 109. 50" D.5 119.9 54.7 52.0 203.6 46.7 225. of these figures.1 233. Chev. you may wonder why some cams are designed to open the valve farther. The extra flow is gained on the flanks of the lift pattern.1 81. B 60. Norton 850.9 101. By measuring the flow at each valve lift with and without the intake manifold. The answer is that in order to open the valve more quickly and longer at lower lifts.25" D.5 102. Even well modified heads will generally only ~btain 80i. 1.3 50. 1. These figures represent the maximum air-flow which can be expected under optimum conditions of port and valve seat design. 72" D.2 50.B 21B. It is the total flow with the intake manifold installed which must be used in formulas 3 and 4 described on pages 12 and 13. The head-flow figures shown in Fig. Fig. Chev. When the intake manifold is installed the total flow will drop off from 5~ to 30~.9 112. The maximum potential flow for some of the popular heads are shown in the comparison chart in figure 5 at 10" of water test pressure. 1. Small Block.2 .05 15.4 If the flow reaches a maximum value at a lift of about .2 10B. Chrys ler Hemi. 1. . Yamaha TX 650.10 cfm ~ lU" test pressure 56. it is necessary to "over-shoot" the maxtmum head-flow point. Westlake.8 153.25 .6 146. 3 33.05 7.2 13.2 58.5 45.15 .5 29.0 27.8 25.7 33.6 12.6 77.9 67.10 .3 . In most designs. 8 104 32.0 38.6 85.6 16. even with equal valve diameters.2 42.2 45.8 30.8 25.25 cfm per sq.6 12.4 9.2 13.3 24.0 111 .5 84.0 64.7 19.25 cfm per sq.6 51.4 27. inch valve area 15.6 16. These two advantages add up to an average flow advantage of 16% at higher lifts.5 29.20 .785 (D\a1ve 2 From a flow stand-point a herni-shaped combustion chamber has a clear advantage over the wedge.5 98.4 52.0 46.3 33.8 52.8 22.6 43.2 21. 5 22.7 19.7 41.5 22.9 68.0 42.0 36.20 .• 1 54.4 9.3 58.0 95.4 38.0 19. inch valve area 15. . When you consider that a herni-combustion chamber also generally permits the intake valve to be 10% greater diameter than a wedge.6 51.15 valve diameter.0 41.21 Fig.6 86.30 28.5 35.6 43.1 79.5 53.8 . Until the valve lift reaches . the hemi-port is also straighter -due to the valve angle.4 99.10 .1 73.0 50.2 61.5 71.8 49 .0 47.0 50.3 24.6 37.4 74.2 77 .0 57.4 27.0 95.0 50.7 41.6 77 .2 78. 8 22.8 25.5 71.0 19.0 82.3 64.4 38.15 .8 .8 60.5 66.7 91.2 Valve area = .1 101 104 For wedge intake valves Valve Lift/Diameter Test Pressure 3" 5" 8" 10" 15" 20" 25" 28" 36" .0 36. 6 Valve flow potential at various test pressures For herni-intake and all exhaust valves Valve Lift/Diameter Test Pressure 3" 5" 8" 10" 15" 20" 25" 28" 36" .30 33.6 82.2 58.6 87. there is little difference.2 21.05 7.9 68.2 45.7 92.0 74. it is easy to understand the success of the herni-head racing engine.5 89. but at higher lifts the hemivalve is usually less shrouded.0 64. strive for high turbulence and minimize the distance from the spark plug to the f~the~ part .0 Combustion Chambers In most engines. and the differences are mostly due to combustion chamber effectiveness. Even the degree of turbulence will change.15 foot-pounds per CID. a good combustion chamber will develop 1. The more turbulent chamber will also burn more rapidly and .22 8.produce up to 10% greater power from the same initial charge. Most gasoline burning racing engines use a compression ratio of between 12 and 13. while a highly turbulent combustion chamber might only require 33 0 BTDC advance (27 0 ignition delay).25 to 1. For example. . though not without an outstanding combustion chamber design and ram-tuning. For instance. a smell-block Chevy with a normal combustion chamber shape might require 42 BTDC maximum spark advance (35°.5 to 1. One way to judge a combustion chamber's performance is to measure the torque output per cubic inch of engine displacement. and combustion chamber effectiveness. the compression ratio. In general. regardless of engine design. Perhaps it should be the other way around. Most combustion chambers just don't combust as well as they should. There is plenty of room for improvement. At times combustion chamber burning complexities can make it very confusing when trying to compare cylinder heads on an engine. At the RPM of peak torque. Combustion chamber improvement is more of an art than a science and so trial and error methods are frequently the only choice. Most racing Detroit V-8's only reach 1. it is difficult to compare a cylinder head on a Chevy 302 and then on a Chevy 330.of the combustion chamber. Hemi and pent-roof combustion chambers are generally the best with wedge chambers being 54 to 10~ worse. it appears that the combustion chamber design was dictated by the choice of valve geometry. While the same head will bolt onto both engines.5 foot-pounds per CID.ignition delay). A second guide line for judging efficient burning is the required spark advance for maximum power. It may be possible to raise this as high as 1. The more efficient combustion chambers have higher turbulence and require less spark advance. If the cylinder is completely filled. A turbulent combustion chamber substantially reduces the "ignition delay" time between when the spark fires and the charge begins to burn rapidly. It isn't. These factors can mask differences due to the flow capacity of the heads and confound even the experienced engine builder.30 footpounds of torque per CID. you would expect that the torque per cubic inch of engine displacement would be the same. and RPM range will all change. Fig. To obtain the inlet system length.000 8. The 2nd pulse is best. and then in again toward the valve. The greatest benefit will occur at about 3% below 8000 RPM. a pressure pulse bounces back out the intake tract. corresponding to the 2nd. 3rd and 4th time the pulse arrives at the valve.ad center of the next intake cycle. the "pulse will actually work to decrease engine power. a strong pulse has been transmitted through it. 7 Harmonic 2nd 3rd 4 th 0 Inlet pulsation chart Length formula l32.000/RPM 74. the length is from the valve to the plenum chamber. and then back to the hammer end. The pulse will actually cause the bar to jump back towards the hammer! While the bar (or the air in the port) moves very little. at 8000 RPM for the 2nd harmonic: length 132. .0). shoving extra air in and keeping exhaust gases out of the intake port. Below 7120 RPM or above 8640 RPM. imagine that one end of a steel bar is placed against a hard surface. divide the number shown by the RPM for peak HP as determined by the flow measurements (see Section 3. There are actually several pulses which can be used. The pulse in the example will benefit from 89% up to 108% of 8000 RPM. By making the intake tract the proper length. For example. If the other end is struck with a hammer. the returning pulse can be timed to arrive at top de.000 a: 16. When the inlet valve closes. or from 7120 RPM up to 8640 RPM.000/RPM Lower RPM 89% 91% 93% Upper RPM 108% 104% 104% Pulse Strength* + + + - 10% no 4% * Pulse strength varies with inlet flow and inlet valve opening The chart in Figure 7 shows the pulses which can be used. Both the kinetic energy and the resonant pulses can be harnessed to fill the engine cylinder at volumetric efficiences up to 130%. For engines with a plenum chamber type intake. volumetric efficiency is limited to 100% without supercharging.23 9. To use this pulse. The pulse will help only through a narrow range of RPM. a strong pulse (the hammer blow) will travel down the bar to the other end. the others being weaker and shorter. To visualize what occurs.0 Dynamic flow effects Engine volumetric efficiency and power can be increased considerably by taking advantage of the natural dynamic effects which occur during the intake cycle. Without these dynamic effects. the intake port must be the correct length. Above or below a certain range the pulse will actually decrease power so proper synchronization is essential.5" This is the desired length from the intake valve to the air inlet entrance.000/RPM 97. .. E u ~ . 8 Crank Angle .:..--.... . - ! . ...-+ ...1.--+-.t -.-. --.. -----. ... ~ . .I -.._..-' . .. . : .."-':' ----:.. so this must be measured. of engine flow in cfm/in~ versus degrees of engine rotation.. t ----r °6·0~0~~~--~T-D~C--~--~---------9~00~--------------B~D~C----------~6~00~~ Fig. . i .q.and then the valve closing timing can be determined from Figure 9.~~:-t-~:··-~ .0 Inertia-supercharge effect When the intake valve starts to close.•.----. I ..--I .:--~~---f--""'...·:·-··+-:-Ir..-+-_-+--_~--+"-'_-_-_·+I_~_:-:+j-.. valve lift for the complete intake system. - ! I ' I . ---~---.'-- c.- . :•i... 1 I ... .. : ... . 80 . c( ~1--_+___1r_~--+_-~--+----__~-_1-1.tion ~:---'----------~ ... ~-: .. The intake flow rating (see Section 10. I . ic 60 .~ . -.'---+--TD•• I . .- 20 +--I~~-~. If the inlet valve is closed at just the right instant. 0 ". I I -. :R:1:-: :--1:-.. Z depends on the average inlet valve area. 1 .. I ~.-. ~w :.. .rI . .- "" 0 ~ r . I ' t:::c I.' .'.3 or greater for significant benefits. .----+.... . I ! +----~>---~-~+-I-- ... I' .... 10.0) must also be 0... ----... ~ .. .c e.I . -. I i~ak..: I .I .. Next determine the cam lift profile at the valve versus the degrees of engine rotation.-·-+-----~r-.. From these two pieces of data A construct a graph. ... . . the fast moving air column tries to keep ramming itself into the cylinder. Openings of 20 0 to 40 0 btdc are usually preferable.' . ~ .. ~. -.'.~--- I " I j --------l . .-.... --i --. . This is a plot of the total engine flow considering both the intake system and the cam • .1. ..--.. I ' I " ---~-T-" :-+-I ~'-T'''-.-! -......dU~. it is necessary to determine the inertia supercharge index. as shown in Figure 8. ..... I'" ."'.. J . .•. -.02 times the valve diameter by 150 btdc. To determine the proper valve timing for maximum inertia-supercharge. First determine the inlet flow vs.. 40 -t- . Volumetric efficiencies up to 1301 can be obtained. Z. i' I ..24 To obtain benefits from the pulsation. I. ... ... it is also necessary that the intake valve be open to a lift of at least ... . -:. - I --I. the extra charge will be trapped in the cylinder (called inertia-supercharging). I I . I . I .. \' I I . . • ' • • -+. i j i -I - -'- - '-J ... f~"'i -.25 Count the number of squares under the flow curve and divide them by the total number of squares beneath the 87 cfm line... 1 • . . j: .~ . -. ' t '.45 for good engines. ~. t---:----'--:--· ' :. j.j._.10 60 abc LID • . and is also a measure of the strength of the inertia-supercnarge which will be obtained... from the formula below: 8.. Z....' -.. ~i j • j' . : -- '. : 1: : -+ .. i -! I " -: I . .. .-..8~0~~----~~~----~~--~--~~~~--"~--~--~~0~~----~0 . 7. t~:. I ------.... ~ o Fig. . This is a ¥otal rating of the intake system flow for any engine. . . ----~l----- -~ -. - I t ..2 N.. I I ~~j--- • - ~ -4- ___ .. . .~ i -_:- ---'1---. ~ ..35 and 0.. . inches Now this data can be used to determine the inertia-supercharge index.9 and 1.~- .:_.---.1~~~~: -"~-~~:-~~---. -. '. Z IC RPM 126.--::--!------'1'-'. When Z has been determined. -+- .I :. use Figure 9 to obtain the correct intake valve closing angle where the valve should be closed down to a lift of .+-1-'--·~.. i .. .... The average inlet valve area is the Cv ttmes the intake valve area.j. L ____ .. I I -I". ..2. The number obtained is the intake system flow rating Cv.:. I r f - l j. '..: .-TI : .. 1':-~~ L.~~-...---~+ .3 1. .. I. - Area under flow curve Total area under 87 cfm line The C will generally be between 0.- . . 1..! -..0 I • -. the better the engine. . 9 0 100 20 300 Intake Valve Closing Angle at 400 50 . .1 --:. j '" •.---- l I ' ! .. . average inlet area E Cv x Valve area in sq... The higher the Cv.000 CID x Inlet Length average inlet area where CID is the displacement of one cylinder in cubic inches and the inlet length is in inches.4P-------~--------~1----~--~--~----~--~----~1--~~--~ 1.9 ' ' -.i . 'TT i -.--. .. 1 1. I I .1I . . I ' . Z will usually be between 0.-J. -~ . -.--: 1.__ 1.-- ~ -~ ---'--~+~~-:-'1-~-~~~"~.10 x valve diameter.. I" • . --~. .. 3 174.27 1.05 2.06 .12 1.913 .943 1.894 .655 .293 .7 444.789 30" 3S" 40" 45" .12 1.S29 • SOD .69 1.18 1.00 1.00 1.935 1.3 256.837 .00 Example: If flow is 65 cfm at a test pressure of 5".707 .65 2.00 .483 .00 1.22 1.00 .707 .39 2.6 cfm 47.6 185.4 146.08 1.791 .447 .531.9 123.00 1.632 .882 .926 1.866 .894 1.SOO .82 1.15 1.73 1.87 2.45 2.447 .41 1.00 .816 .54 1.89 1. .00 1.00 .53 1.816 .7 78.378 .07 1.6 391.667 .00 .5 cfm FLOW RATE VS TEST PRESSURE Test Pressure 1" H20 Peak Velocity 66.46 1.00 1.SOO .24 2.5 3" 5" 8" 10" 12" 15" 20" 28" 30" 35" 40" 45" 65" *Flow thru a perfectly streamlined orifice with an area of I square inch.83 3.354 .845 .394 10" 1.31 1.SOO .535 .37 1.333 7" 1.683 .64S . what would flow be at 15"? cfm = 65 cfm x 1.12 1.65 3.58 1.592 .632 .654 .12 1.707 .00 .37 2.32 1.58 1.04 1 .0 FLOW-8ENCH TEST PRESSURE CONVERSION CHART Want Flow At: 3" 3" 5" 7" 10" 12" 15" 20" 25" 28" 30" 35" 40" 45 11 1.408 .764 .274 .945 . « -0 u.422 .8 61.26 11.631.548 .2 fps 114.29 1.516 15" 2.73 = 112.29 1.44 1.13 .745 3.837 .612 .0 87.756 .83 1.41 1.00 2.3 362..07 2.4 296.418 .586 .26 1.53 1.693 .87 2..67 1.10 1.471 12" 2.151.55 1.894 .655 .06 1.845 .577 20" 25" 28" 3.00 2.41 1.42 3.411.1 95.548 .18 1.774 .845 .6 106.12 .966 .73 1.577 .16 3.00 .0 350.24 1.7 JfCFM/In 2 27.775 .22 .346 .34 1.0 151 .09 1.24 1. ~ 10 > CII :I: 2.2 209.598 .913 .774 .20 1.7 148.18 1.22 1.71 1.816 .00 .29 1.50 1.1 163.58 2.3 229.00 2.447 .258 5" 1.73 1.94 1.0 187.577 .6 418.327 .866 .1 222.732 .89 2.387 .1 533.316 .707 . Obert. call (800) 826-6600 to order. Yagi Design Refinement of Induction and Exhaust Systems using Steady-State Flowbench Techniques 1972 by G. .F. 861 Lawrence Drive.50 for each paper requested. Colin Campbell Robert Bentley. Feb.) Haessner Publishing Co. 1973. NY. Send along a fee of $3.. John Wiley & Sons.E. International Textbook Co.Y.. Technical Papers S. 700122* Research and Development of High-Speed. 2nd edition.. (Search Engineering Library) Internal Combustion Engines. Small Displacement Honda Engines 1970 720214* by S. PA. HighPerformance.. Pennsylvania 15096 (412) 776-~841 Request a Current Year Catalog or state by number and author and paper title listed below.0 Suggested Additional References Gas Flow in the Internal Combustion Engine Annand and Roe. CA 91320 (805) ~98-6703. (Search Engineering Library) The Sports Car Engine. Classic Motorbooks. Edward F.A. Osceola. (Search Engineering Library) The Internal Combustion Engine in Theory and Practice.A. Charles Fayette Taylor. Technical Papers may be obtained by contacting Society of Automotive Engineers. (out of print. Scranton. Public Library) The Theory and Practice of Cylinder Head Modification David Vizard. Inc. WI. Newbury Park. 1974 (out of print.E.95. N. Leydorf. Haynes Publishing Co. S. 400 Commonwealth Drive Warrendale. Tuning BL's A-Series Engine David Vizard.27 12. 790484* An Analysis of the Volumetric Efficiency Characteristics of 4 stroke Cycle Engines Using the Mean Inlet Mach Number. 1985. Jr. INC. F~14-$19. 2nd Edition.March 1979 by Itaru Fukutani & Eiichi Watanabe . Copyright Act without permission of copyright owner is unlawful.E. *All papers belonging to S.s. . Dynamic Flow Coefficients Feb. are covered by u. Publishing Division. $12. 1982 by Masaaki Takizawa Tatsuo Uno . 1982 by Itauru Fukutani & Eiichi Watanabe 820410* A Study of Gas Exchange Process Simulation of an Automotive Multi-Cylinder Internal Combustion Engine Feb. Request for permission or further information should be addressed to SuperFlow Corporation.E.95.28 820154* AirFlow through Poppet Inlet Valves Analysis of Static . Toshiaki Oue Tadayoshi Yura Bosch Automotive Handbook from SAE Publications.A.A.s. Reproduction or translation of this work beyond that permitted by Sections 107 and 108 of the 1976 o. Copyright laws and cannot be reproduced without paying a fee or obtaining permission to reproduce from S. SuperFlow reserves all rights for these instructions worldwide. 4 I I - it- ..A~OO SCALE 1/:11.7~ V-8 ADAPTEA.D . : .. 1'1 00 -1 J I I ! 1 ANGU X:I:' B Sac. I I I . r. . TOTAl UGt:ND "[LUS[ FOIl PROO OAT[ 3 .L . Y SF .. I I ··S' . .''I .. . I ' : I I I '" I 1-•.. ..Au. I I -1 . J -rNiltu 1 • I ' l. I l. -1r-/i-- 1 '" f .. CHECKE" A MATUIAl eLlA" Ae:IJYLlC. EN r <SLVIt. I I . I . J J I : 01 . ~ C I I I~ r. I 1I II'. 4 3 2 1 . E~5 a.J 11 . I I . I - - I I -1 t-. ALL JOIN r" SCAAPE' ANP !¥1IVi"B . IDENTlneAT N MilE" MANUrACTIIII£ 'AIIT NO I DOC MANUFACTUR[" NUT ASS[1IIt1tt. I I I I I I ...... Turn machine on and place finger over small hole in test plate. then settle back to zero with machine running. (303) 471-1746 and ask for flowbench customer service. Shut Intake Control Valve. Repeat test in Intake mode. (4 places).TROUBLE SHOOTING YOUR FLOWBENCH When there seems to be a problem with the flowbench measuring system. In that case. Repeat this test on exhaust. Slowly. call SuperFlow. Reconnect the tubing to the elbows. Record flow meter reading. If not. Repeat test in exhaust mode:-- 3) HIGH FLOW TEST You should still be in the exhaust mode from the last test. Then. unscrew the 3/4" hex assembly until the elbows point toward the tubing. making sure fluid responds and settles back to zero smoothly. do the following: 1) Unplug the brass/plastic tubing from manometer elbows. switch to intake mode. ---- After recording the collected data. please run the next three tests. Turn the machine-on and open the exhaust valve until you get 10" of test pressure on the vertical manometer. Turn flowbench back on. Record reading of horizontal manometer. NOTE: Sometimes the flowbench won't go to 10" of test pressure. The data you collect will be helpful in evaluating your problem. record reading. Unscrew elbows from the 3/4" nylon hex until they are flush with the top of the hex. Horizontal flow scale should rise slightly. Using spare plastic tubing puff or suck into each manometer elbow. with both holes in test orifice plate plugged. adjust to 8" of test pressure and record the flow reading. Start by removing all rubber stoppers. 2) LOW FLOW TEST Same test as above except remove finger from small hole and slowly open intake control valve until you reach 10" test pressure on vertical manometer. Shut exhaust valve. 2) 3) If problem still exists. 1) NO FLOW TEST With SuperFlow's test orifice plate bolted on and all rubber stoppers tightly in holes. adjust intake control valve until you reach 10" of test pressure on vertical manometer. top and bottom. . Connect the four flexible plastic tubes onto the four meter Inlet tubes. Reise or lower the left side of the manometer until the level bubble Is centered between the two merks. Open the plestic fluid velves on both metere [4 valvee. Reed the instructions on the small red end white teg etteched to the flow meter. To keep the fluid insids the manometers during shipping. then re-tighten the screw. the clear plastic tubes have been disconnected and the velves have been closed. Turn the on . C.} B. the valve is open. MACHINE PLACEMENT Remove the Superflow 110 from its shipping carton. If the fluid column moves end returns freely. Check the valves to make sure they are open by blowing gently Into each valve. . Do not lift it by the plastic geges on the front panel. using the extrs length of plastic tubing provided. Level the n1I!lnometer by turning the screw near the left end of this manomater clockwise to loosen it. 2. Place the Superflow 110 on e level table top. A bubble level Is built Into the flow manometer.off switch to OFF and plug the Superflow in. INSTRUMENT CONNECTIONS AND SETUP A.Superflow 110 CHECK-OUT INSTRUCTIONS ~ 1. Zero the scele on the verticel test pressure manometer by rotating the knurled nut et the bottom of the scale. If you purchased a cylinder heed adapter. Remove the plastic adepter. loosen the thumbscrew et the bottom of the flow menometsr end slide the scele to align the zero merk with the left end of the red fluid column. E. but install the bolts and flat washers in ell four corners. Leave both the 1 7/8" and 5/16" holes in the test orifice open. OPERATION CHECK A. Remove all rubber stoppers from orifice plete at the top of the flow bench. it is mounted to the flow bench baee plate on top of e flat test orifice plata. . 3. To zero the flow-percent scele.D. note thet this is the 185 cfm flow range. C. Mount only the aix-inch aquare test orifice plate to the flow bench. B. By referring to the flow chart. *Notice: The output of the SuperFlow 110 is proportional to the ~ine voltage at your location. Power Requirements: SF-110 is 110 VAC or 110 VDC electrical power and draws 15 AMPS SF-II0E is 250 VAC or 250 VDC electrical power and draws 8 AMPS This completes the check-out test. 80907 (303) 471-1746 eX. perform the check-out tests (starting at OPERATION CHECK D-E) at 8 n of water test pressure. If a test pressure of 8.* Turn off the machine. the unit may have been damaged in shippment.S. SuperFlow Corporation 3512 North Tejon Colorado Springs. Switch the mode control ewitch to intake and repaat the above etepa with the inteke flow control valve. If the SuperFlow 110 meets the above figures. * E. If a test pressure of 8. If the SuperFlow 110 will not reach 10 M of test pressure through the test orifice plate.D.Customer Service . it is ready for flow tests. or 240 VAC for foreign units. Remove the test orfice plate and install the cylinder head adapter. U.0" is used the flow should be 70% to 74%. Set the mode selector switch to exhsust snd turn ON the off-on switch. This does not have any effect on the accuracy. The flow should be 78% to 82% on the scale. If the SuperFlow 110 fails to meet the above standards. The flow should be approximately 83% to 87% on the scale. Close the inteke flow control valve gently ageinst its seat end opan ths exhaust flow control valve until the test pressure reeds 10. Turn off the machine.0" i~ used. Colorado. Observe the reading on the upper diegonal flow meter.0" on the vertical meter. the flow reading ~ ehould be 74% to 78%. Please call the SuperFlow headquarters for further instructions. At voltages below 120 VAC. the SuperFlow maximum capacity will be less than normal.A.

Comments

Description