4a inlet manifold vs 7a inlet manifold Options

[normality78]

It may sounds abit silly question but i was wondering, does anyone of you guys here did have a look into the differential of 4A and 7A inlet manifold design? I had some discussion with my fren today whom having 7A with 4A inlet head and inlet manifold, i asked him why not opt 7A inlet manifold which he said 4A inlet runner seems to be bigger hence he do think it flow better. what u guys think?

[Kwanza26]

no they don't interchange and no... the 4A manifold... as in 16V 4A manifold is not better.

[normality78]

oh, pardon for my mistake. i didnt make it clear. Im comparing about 4AFE and 7AFE inlet manifold.

[FallenHero]

not quite sure what you're asking... But the design of the manifolds is what I Think you are talking about. In those terms the manifolds are set up for the engine. 4a (red top) is a high rev, high hp, relatively low torque engine... thus it has big shorter length runners.

7a, being a low rev low hp, higher torque engine, has smaller longer runners.

if you are talking about somehow fitting a 4a manifold onto the runners of a 7a manifold... they don't line up... does not compute, do not pass go.

This post has been edited by FallenHero: Jan 20, 2007 - 9:50 PM

[normality78]

Alrite. Yeah, i guess what im asking wasnt clear enaugh. pardon my bad english. Im not talking about GE head and inlet manifold. I just wonder does anyone did take the effort and look into the 2 FE head inlet manifold difference

What im trying to ask is, comparing 4AFE and 7AFE inlet manifold design. The runners dia size, shape and the length. As i can see, the 4AFE runner shape was an oval shape port and 7AFE was 2 mini round port. Based on raw eyes judgement, 4AFE inlet manifold runners seems to be bigger, hence shld it be more flow? Another thing is the intake plenum design of 4AFE more on round shape whereas 7AFE is more square.

yeah, i do know 7AFE and 4AFE inlet manifold cant be interchange but the head does. So its not a big issue to me. I just wanna maximise my inlet manifold flow. Soon im going to bore my TB as well. Initially i do thought of changing into GE head but the distributor doesnt fit and i was being told i need a stand alone ecu for it if im going to do it. so i scrap off the Ge head swapping plan.

hope i did make it clear this time round

i've attached my 4AFE inlet manifold and 7AFE inlet manifold

4AFE


7AFE

[soulshadow]

Give or take, I'd go with the 4AGE. The 7A looks poorly designed. and the 4AFE looks worst then antyhing I've seen.

[Kwanza26]

I already answered your question. NO... there is no performance increase because, believe it or not... intake manifolds are tuned to the head's design and flow capability. Also, yes I have compared all 3 of the different manifolds you've mentioned (4AFE, 7AFE, 4AGE) and no... the 4AGE manifolds are NOT better. No, the 4AFE manifold is not better. Each was designed for their given engine. Also, the 7AFE intake manifold, the one in the picture does not have dual runners. Some 7AFE's did have dual runners (not in the US) but that was designed for TVIS and intake flow was physically limited to affect the torque curve. The dual runner manifold cannot be swapped with a single runner manifold because the intake ports on the head are typically different...

This post has been edited by Kwanza26: Jan 22, 2007 - 2:48 AM

[normality78]

I already answered your question. NO... there is no performance increase because, believe it or not... intake manifolds are tuned to the head's design and flow capability. Also, yes I have compared all 3 of the different manifolds you've mentioned (4AFE, 7AFE, 4AGE) and no... the 4AGE manifolds are NOT better. No, the 4AFE manifold is not better. Each was designed for their given engine. Also, the 7AFE intake manifold, the one in the picture does not have dual runners. Some 7AFE's did have dual runners (not in the US) but that was designed for TVIS and intake flow was physically limited to affect the torque curve. The dual runner manifold cannot be swapped with a single runner manifold because the intake ports on the head are typically different...

Alrite. Get it. So any suggestion what i can do to improve flow?

FYI, the pic showed was really a dual runners.





This post has been edited by normality78: Jan 22, 2007 - 3:08 AM

[FallenHero]

only thing you'll feel is a turbo.

Save your money and spend thusly.

I already answered your question. NO... there is no performance increase because, believe it or not... intake manifolds are tuned to the head's design and flow capability. Also, yes I have compared all 3 of the different manifolds you've mentioned (4AFE, 7AFE, 4AGE) and no... the 4AGE manifolds are NOT better. No, the 4AFE manifold is not better. Each was designed for their given engine. Also, the 7AFE intake manifold, the one in the picture does not have dual runners. Some 7AFE's did have dual runners (not in the US) but that was designed for TVIS and intake flow was physically limited to affect the torque curve. The dual runner manifold cannot be swapped with a single runner manifold because the intake ports on the head are typically different...

Alrite. Get it. So any suggestion what i can do to improve flow?

FYI, the pic showed was really a dual runners.

[normality78]

Im already on turbo

[Bitter]

that looks like he 7afe with TVIS, most DID NOT have TVIS however and just have an oval intake port.

[normality78]

yeah, mine was with TVIS but i've since removed all the mini flap inside. Im still thinking what can i do to improve my head flow without spending a big fortune or complicated it

[FallenHero]

basically, there is no amount of quality porting that can be done to an economy box engine to Really increase power. If you want more power, bull the stock pistons and rods and replace with performance versions, and boost the living hell out of it. If you already have a turbo, that's your option... assuming that you are currently running in the 6-8psi range with upgraded fuel pump and FMIC.

[normality78]

basically, there is no amount of quality porting that can be done to an economy box engine to Really increase power. If you want more power, bull the stock pistons and rods and replace with performance versions, and boost the living hell out of it. If you already have a turbo, that's your option... assuming that you are currently running in the 6-8psi range with upgraded fuel pump and FMIC.

im boosting 1 bar now with S15 fuel pump. Using FMIC GSR intercooler. Piston do in consideration now but i just do not wan the head flow to be my bottleneck tats why im posting such question

[Kwanza26]

im boosting 1 bar now with S15 fuel pump. Using FMIC GSR intercooler. Piston do in consideration now but i just do not wan the head flow to be my bottleneck tats why im posting such question

Unfortunately the design of the head will limit top-end power based on your set-up. AND... you're boosting 1 bar? How the heck is that poor 7A holding up. I'd worry less about performance efficiency and more about the rods snapping like twigs. FYI, the FE head has proven to perform very well under boost but generally only under 7000 rpms or so. You can still make power above that... but flow inefficiency... or shall we say the inherit design will limit its ability to make top-end power comparable to GE counterparts... but the low-mid-range will be much stronger.

If you want more information... post more about your set-up.

[normality78]

Well i've been boosting for 1 bar for about 8 months. So far the motor is still keeping up. But i don't whack it that often as well since im still in auto gb.

nothing much on my setup though. Its still stock internal, previously on IHI RHB52 turbo but now i swap to wrx td04 coz i cant get the same turbo to replace. 2.5" downpipe follow with 2" all the way back end with RSR magII muffler. Running front mount GSR VR4 intercooler. using 4EFTE injector control by emanage blue with haltech 3bar map sensor. basically thats all about it.

[dans_st]

I am planning to (still figuring out details), but wouldn't it be beneficial to use the dual runner head and intake manifold and siamese them both, wouldn' tthis raise your powerband of the 7AFE as well as allow more airflow????
I am as I said in the beginning stages of this and am still trying to do more research to find out more about this idea, but in THEORY it would be better wouldn't it?????