Intake Manifold Flow Test
Thread Starter
Joined: Jul 2003
Posts: 10,755
Likes: 7
From: Valencia, Ca
Intake Manifold Flow Test Data 
Steves words verbatim
I had some time yesterday to flow test the manifolds on your Patriot head. I flow tested using cylinder 5 runner as before. The Edelbrock is a dual plane manifold. On that manifold I first flow tested cylinder 5 runner which pulls from the high side of the plenum, then turned the manifold around and flow tested cylinder 4 runner which pulls from the low side of the plenum chamber. The low side generally flows better on dual planes because the runner has a straighter shot from the plenum.
The sheet metal manifold has really short runners. The actual runner centerline length is 3.75" down the centerline. This results in a plenum to valve back length of only 9.25". This would be too short a length to give adequate pulse tuning within the rpm range of a normally aspirated engine of this type. Work good at nine grand but that's outside the range of most engines. In any case, this manifold is going on a twin turbo engine. Should work fine under boost.
The Weiand manifold keeps up the the Fast up to .250" lift. Past that point the Fast takes off. I don't think this is due to the runner shape. I think this is a function of throttle bore size. Same holds true for the Stock LS6 manifold which has the smallest opening of those tested.
Sheet metal 91.5 mm throttle bore opening
Fast 90.2 mm
Weiand 78 mm
LS6 75.5 mm
If one were able to rework the LS6 manifold for a larger throttle bore, I'm sure the flow numbers would improve substantially. This manifold was bone stock. Both the Fast and Weiand were cleaned up internally and port matched.
The Edelbrock, as I mentioned above, is a dual plane manifold. This again was bone stock. The runners are smaller in cross section than on any of the other manifolds tested. Porting this manifold would help but it is difficult getting inside to rework a dual plane. I cut them open to rework then weld them back up. Too expensive to do unless it is for some sort of restricted racing class. I would like to flow test a GM or new Edelbrock single plane to see how those flow. In any case, the low side runner on the Edelbrock flowed quite well considering it's size.
Steve
The sheet metal manifold has really short runners. The actual runner centerline length is 3.75" down the centerline. This results in a plenum to valve back length of only 9.25". This would be too short a length to give adequate pulse tuning within the rpm range of a normally aspirated engine of this type. Work good at nine grand but that's outside the range of most engines. In any case, this manifold is going on a twin turbo engine. Should work fine under boost.
The Weiand manifold keeps up the the Fast up to .250" lift. Past that point the Fast takes off. I don't think this is due to the runner shape. I think this is a function of throttle bore size. Same holds true for the Stock LS6 manifold which has the smallest opening of those tested.
Sheet metal 91.5 mm throttle bore opening
Fast 90.2 mm
Weiand 78 mm
LS6 75.5 mm
If one were able to rework the LS6 manifold for a larger throttle bore, I'm sure the flow numbers would improve substantially. This manifold was bone stock. Both the Fast and Weiand were cleaned up internally and port matched.
The Edelbrock, as I mentioned above, is a dual plane manifold. This again was bone stock. The runners are smaller in cross section than on any of the other manifolds tested. Porting this manifold would help but it is difficult getting inside to rework a dual plane. I cut them open to rework then weld them back up. Too expensive to do unless it is for some sort of restricted racing class. I would like to flow test a GM or new Edelbrock single plane to see how those flow. In any case, the low side runner on the Edelbrock flowed quite well considering it's size.
Steve
i can post up each individual flow sheet if anybody wants them.
Last edited by jrp; Mar 22, 2005 at 11:49 AM.
didn't realize the ls6 flowed so well...i guess those numbers are even slightly skewed because where as the ls6 was bone stock...
Both the Fast and Weiand were cleaned up internally and port matched.
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Originally Posted by v8maro
Nice, let's get an ls7 on there and see what it does.
TECH Addict
Joined: Dec 2004
Posts: 2,178
Likes: 627
From: Florida
Originally Posted by 777
didn't realize the ls6 flowed so well...i guess those numbers are even slightly skewed because where as the ls6 was bone stock...
The sheet metal intake is a spectrum 5 racing piece. It is similar to the Nasty Perf. manifold. The sheetmetal, Weiand and FAST 90 are mine, the sheetmetal is going on the car for now, we'll see how it works out. Steve is a great guy and I appreciate all of his efforts, I'de like Steve to flow an LS2 and a single plane as well, which I have access to...Dave
Thread Starter
Joined: Jul 2003
Posts: 10,755
Likes: 7
From: Valencia, Ca
Originally Posted by 427 LS1
The sheet metal intake is a spectrum 5 racing piece. It is similar to the Nasty Perf. manifold. The sheetmetal, Weiand and FAST 90 are mine, the sheetmetal is going on the car for now, we'll see how it works out. Steve is a great guy and I appreciate all of his efforts, I'de like Steve to flow an LS2 and a single plane as well, which I have access to...Dave
i forgot who steve said he got the manifolds from. 
