restrictive intake manifold(pics)

[Beemik]

Here are some picture of inside the intake manifold of the 4/7afe. This thing was desinged with one purpose; to restrict the air flow to the engine




And they sure did a good job. I think I'll be making some changes.

[Flashmn]

Those runners look actually pretty good. I doubt they'd restrict _that_ much. Besides your head is a worse restriction.

[Beemik]

Ya the runners do look pretty good. You can't see it that well in this picture but the line across the bottom of the runners is about an 1.5 inches high with those two boars being a seperate cavity

[Beemik]

Sorry I meant in the pervious picture.

[Flashmn]

Thats not going to act as a restrictor... just FYI.

[Bitter]

doesnt look that bad, i've been wondering what it looks like in there. iirc that chamber is to control sound.

[Flashmn]

and to control air dispersion... anyways plenuum volume is more important and the shape.

[Bitter]

i've seen worse stock manifolds, ever seen those of the 2000-2005 2.4L 4G64 in the Eclipse? NO plenum! just runners and a throttle body.

[Beemik]

i was thinking something like this.
Also like you said Flashmn about volume i was thinking about milling a 10mm spacer to put between the upper and lower. Very rough measurments; about an extra 200cc in the chamber. Any thoughts?

[Criard]

Originally Posted by Beemik

i was thinking something like this.
Also like you said Flashmn about volume i was thinking about milling a 10mm spacer to put between the upper and lower. Very rough measurments; about an extra 200cc in the chamber. Any thoughts?

I know nothing about the inner workings of intake manifolds. but I can kinda see how it works, and I see what you're trying to do. my only thoughts are.... 'intriguing'

I would probably think the same thing as you, and contemplate doing the same thing. Good luck if you decide to go through with it!

[Bitter]

let us know how it goes and be sure to keep us updated. if theres good gains i'll get a spare from the junkyard on the 1/2 price day and try it too.

why not remove the whole wall and then make the knotches?

[Beemik]

There doesn't seem to be enough room because of the way the runners curl under. i got this one from the scrap yard for only $20. I also picked up a throttle body that I wanted to boar but the 56mm wont happen. I might be luckey to boar it to 52-53mm, there just isn't enough material. the manifold also came with the fuel rail which I'll paint a really pretty colour

[Bitter]

i see what you mean about the curling, i'm pretty interested to know how this works out since i like cheap/free mods. i can understand your reasoning behind this, its tricky tho how it could effect the engine.

[retiredat44]

Intake castings are left rough because it creates turbulence to help mix the air and fuel better. And, yes, also because it would cost too much for the castings to be machined.



FYI

[Beemik]

The casting of the runners is pretty good! I'll post a close up later. A minor polish wont do too much. Even the ports line up pretty good. And FYI. It's the cost. The castings are rough because of the sand that is used to make the cast piece. Some manufactures use a more coarse sand then others leaving a rougher finish.
The creation of turbulence is required at the piont of injection and below. Runners also become smaller at this stage to increace velocity and reduce wall spray.