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1G head flow numbers and intake designs...long
I have been doing a lot of flow bench data on different intake designs over the past few days and this is what I have come up with so far.
Now the test subject was a totally stock 1G head. It still has the factory valve job and valves.
Here are the numbers that I have collected as of now.
Stock head with no intake and a ¾” radius entry. #3 intake runner. As you can see these are a good flowing head to begin with.
Lift CFM
.050 48.91
.100 94.21
.150 139.62
.200 181.24
.250 216.94
.300 241.11
.350 261.52
.400 271.14
.450 280.45
Stock head with a stock intake. No T.B. with a ¾” radius entry. #3 intake runner. You can see not only does the stock intake kill the upper lift flow like everyone knew, but it hurts low lift flow as well.
Lift CFM
.050 33.75
.100 88.70
.150 128.18
.200 169.87
.250 202.57
.300 223.95
.350 238.73
.400 245.79
.450 252.65
Stock head with a 4” tapered runner sheet metal intake and a 240 cubic inch plenum. No T.B. with a ¾” radius entry, and a 60mm opening. #3 intake runner. You can see were the stock intake out flows it until the .200 lift mark. It will hurt the lower end a bit, but make up for it in the mid to upper RPM range.
Lift CFM
.050 32.02
.100 76.92
.150 128.41
.200 169.54
.250 205.36
.300 233.91
.350 254.90
.400 267.98
.450 274.29
Stock head with 6” tapered runner sheet metal intake and a 240 cubic inch plenum. No T.B. with a ¾” radius entry, and a 60mm opening. #3 intake runner. You can see were this one kicks the crap out of both intakes tested in every lift. Makes for killer low end and top end charge.
Lift CFM
.050 45.28
.100 91.17
.150 140.12
.200 183.17
.250 221.39
.300 243.46
.350 261.52
.400 270.10
.450 278.41
Stock head with 4” tapered runner sheet metal intake and a 540 cubic inch plenum. No T.B. with a ¾” radius entry, and a 60mm opening. #3 intake runner. Now this test was done to see if a bigger plenum does have any effect on non force induction application. Remember the flow bench draws air threw the intake, not forcing air into it. That test will come later on to see the results as well. You can see were the two shorter runner intakes flow a lot alike.
Lift CFM
.050 35.12
.100 61.31
.150 121.32
.200 167.51
.250 205.36
.300 233.91
.350 254.90
.400 267.98
.450 280.45
Stock head with 6” nontapered runner sheet metal intake a 240 cubic inch plenum. No T.B. with a ¾” radius entry, and a 60mm opening. #3 intake runner. Now notice how not having a tapered runner does not fill the cylinder as well. It does out do the stock intake but not well enough.
Lift CFM
.050 35.40
.100 89.91
.150 128.62
.200 170.88
.250 205.36
.300 231.46
.350 252.65
.400 263.69
.450 270.10
I hope to do a complete stage test as above in the next few weeks. I will start with a level 1 head with stock sized valves and go up from there with all the same test shown as above. From what I have gathered so far. I do believe that a aftermarket intake even on a stock car that is tuned properly (intake) to the combination will make more power. Now I am not trying to say go out and buy something like this first, but I do see were it will help out long before a ported race head. I can see one thing for sure. If a stock intake hurts flow that bad on a stock head…..what is it going to do on one that has been worked over?
I would like to flow a stock Extrude Hone intake to compare it as well. If any of you guys have one and are not using it yet I would like to borrow it for a day. I will be happy to pay shipping to and from my shop.
All the test have been performed on a JKM 600 flow bench on the same day under the same conditions. Each intake tested had every runner (except #3) blocked off between the intake and head so that no bleed off air was involved. All vacuum ports blocked and injector hole plugged as well.
Now as you can see what time it is by my post. I am tired and heading for home.
Hope some of you learn something from this.
Polk
Last edited by Polk : 09-17-2002 at 09:19 AM.
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