sources for cylinder head flow numbers



sources for cylinder head flow numbers

Postby grumpyvette » September 24th, 2008, 10:59 am

http://www.purplesagetradingpost.com/su ... eads1.html

http://www.kendrick-auto.com/head_flow_figures.htm

http://www.aamidwest.com/enginequest/eq ... heads/flo/

http://racingdownloads.com/racing_software-26.html

http://www.superchevy.com/how-to/engine ... omparison/

http://www.superchevy.com/how-to/83138- ... ock-heads/

http://www.strokerengine.com/SBCHeadsFlow.html



http://www.hughesengines.com/TechArticl ... risons.php

http://users.erols.com/srweiss/tablehdc.htm

http://www.carcraft.com/techarticles/11 ... index.html

http://www.summitracing.com/parts/tfs-3 ... /overview/

http://www.summitracing.com/parts/tfs-3 ... structions

you are aware theres reasonably priced aluminum heads designed for a small bore sbc that out flow standard vortec heads, so don,t think those are automatically your best option.

look this is not a guessing game (selecting the correct port size, there are known guidelines )you select and verify the correct port size and cross sectional area, using know calculations, valve diam. and flow rate for the application, verify clearances in the valve train, intake runner length and cross sectional area and that the cam lift duration and LSA, and make sure the valve train components are compatible for the intended rpm band and stress levels,
you match the cams intended rpm and power band to the displacement and compression ratio, exhaust scavenging ,make sure the valve curtain area exceeds the port cross section slightly , select the cam lift and duration to maximize the port flow,potential, select headers designed to operate in the same power band, select a drive train that keeps the engine in that power band most of the time.
if you read thru the posted info I will agree that a great many cylinder heads get selected on the basis of posted flow numbers or price alone, and the fact is that the cam timing, intake design,operational rpm band, displacement ,compression ratio and exhaust scavenging all have a pronounced effect on how well the fuel and air flow thru a cylinder head port, and you don,t always get the best horse power by selecting the head with the highest posted and advertized flow numbers.
I'd also point out that the exhaust gases are physically forced out by the piston on the exhaust stroke and given a huge help in exiting the cylinder if you have a properly designed header that scavenges the cylinder,and that rapidly exiting exhaust gas does help to draw in the next intake charge PROVIDED the cam timing and exhaust header are properly matched, and since flow benches measure flow at a static valve lift and engine have a piston rotating at maybe 6000rpm and valve that opens and closes 55 times PER SECOND and theres no exhaust scavenging ,while the heads tested,theres no way in hell that a flow bench accurately duplicates flow conditions in a running engine


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http://www.rbracing-rsr.com/runnertorquecalc.html

viewtopic.php?f=52&t=322

viewtopic.php?f=56&t=1730
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: sources for cylinder head flow numbers

Postby grumpyvette » August 13th, 2009, 9:13 am

profiler new port 210cc SBC heads. 2.055 master valve (it has a 30º backcut) and flowed the head on a 4.125 fixture. Exactly a 90% throat.

http://www.profilerperformance.com/sbc-heads-176.html


.200/158.7
.300/211.0
.400/261.5
.500/285.0
.600/289.9
.700/294.7
.800/294.8

http://www.profilerperformance.com/bbc-heads-174.html
IF YOU HAVE A SET OF REALLY DEEP POCKETS
http://www.speierracingheads.com/SRH2.50.htm

heres some BBC head info
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IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: sources for cylinder head flow numbers

Postby grumpyvette » January 12th, 2010, 2:22 pm

http://www.thirdgen.org/techboard/tbi/3 ... dflow.html


These are the flow results before any port work:
Also posted here: http://www.thirdgen.org/techbb2/show...hreadid=177593 (L98 cast iron heads...at machine shop)

14101083 heads 1.94 intake / 1.50 exhaust
numbers @ 28" of mercury for comparison

Intake
Lift_______CFM__Potential (based on 1.94 valve area)
0.097..........52.................66
0.194..........101...............131
0.291..........145...............196
0.388..........167...............226
0.485..........179...............242
0.582..........185...............253

Exhaust
Lift_______CFM___Potential (based on 1.50 valve area)
0.075..........35.................38
0.150..........62.................78
0.225..........87.................114
0.300..........105...............152
0.375..........106...............165
0.450..........106...............171

The flowbench operates at 10"...I multiply the flow results by 1.67 to get 28" for comparison. The inlet was radiused...and there was a pipe on the exhaust. So...these heads were just that bad, I guess. The heads were stock valve, with apparently some crappy valve job work done on them before. No port work had been done.

Using only carbide cutters, I opened up the intake opening, opened up the pushrod pinch, removed as much casting as I could get to, and pocket ported and bowl blended the best that I could do. Same for the exhaust except I did not touch the exit area, just removed casting, pocket ported some, and tried to blend it and remove the sharp edge on the short side. This was the 1st time I have ever truely looked at a set of heads, much less ported any.

Having said that, here are the results on the same flow bench at the same lifts with the stock valves, and then some stock type Stainless Steel Replacement valves:

Stock Valves
Intake
Lift_______CFM__Potential (based on 1.94 valve area)
0.097..........49.................66
0.194..........100...............131
0.291..........146...............196
0.388..........183...............226
0.485..........200...............242
0.582..........200...............253

Exhaust
Lift_______CFM___Potential (based on 1.50 valve area)
0.075..........35.................38
0.150..........61.................78
0.225..........91.................114
0.300..........125...............152
0.375..........138...............165
0.450..........139...............171

Stainless Steel Stock Type Valves...brand unknown
Intake
Lift_______CFM__Potential (based on 1.94 valve area)
0.097..........54.................66
0.194..........108...............131
0.291..........158...............196
0.388..........189...............226
0.485..........206...............242
0.582..........203...............253

Exhaust
Lift_______CFM___Potential (based on 1.50 valve area)
0.075..........30.................38
0.150..........63.................78
0.225..........102...............114
0.300..........137...............152
0.375..........144...............165
0.450..........144...............171


Side by side comparison
Intake
Lift_______CFM
0.097...52......49....54
0.194...101....100...108
0.291...145....146...158
0.388...167....183...189
0.485...179....200...206
0.582...185....200...203

Exhaust
Lift_______CFM
0.075....35.....35...30
0.150....62.....61...63
0.225....87.....91...102
0.300....105...125...137
0.375....106...138...144
0.450....106...139...144


I think I have done well so far. Heads are cut for 2.02/1.6 valves now. Just need valve job, blend again, polish exhaust, and 80 grit the intake side, and I will be done. I have the Manley RaceFLo Valves to top it off. I will flow test again when I'm finished.

Cutting for the valves cost me $125.

let me know what you think. At least I didn't butcher them. I have seen where others lose flow at the bottom, and gain at the top. I didn't seem to lose much, if any, at the bottom, and gained some on the top. I hope the blending, bigger valves, valve job, and Manley valves will help considerably.

Here are some other stock flow numbers from other posts for comparison sake:
Corvette Aluminum # 113
Lift/Intake/Exhaust
.100 62 49
.200 116 98
.300 161 130
.400 185 152
.500 195 159

350 Cast Iron # 083
Lift/Intake/Exhaust
.100 44 41
.200 101 82
.300 155 125
.400 182 137
.500 196 140
__________________

Here are the flow numbers for my 416 heads.
Both intake and exhaust have been ported. Intake runner cced in at 178.6cc and exhaust 65cc The heads were flowed with a stock 1.84 intake valve and a Manley 1.5 exhaust valve. The intake had a radiused entry in place and the exhaust was straight out of the port. The flow bench was fitted with a 3.8" bore diameter adaptor only because it was the closest size avaliable.

Lift Intake Exhaust both @ 28"
.05 29.4 24.6
.10 57.4 48.3
.15 88.3 75.0
.20 122.1 100.2
.25 152.2 113.9
.30 172.9 128.7
.35 188.7 139.4
.40 201.8 147.3
.45 213.3 152.2
.50 217.8 159.2
.55 220.7 161.2
casting number 14022601 heads. Removed casting flash, gasket matched heads, intake, & exhaust manifolds.
Here are the flow numbers @ 28 in/H20.


Lift Intake Exhaust
.050 35.60 15.00
.100 72.40 47.00
.150 105.8 72.50
.200 133.4 98.00
.250 154.1 117.5
.300 180.6 137.0
.350 195.5 145.0
.400 209.3 153.0
.450 217.4 155.0
.500 224.3 157.0
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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