NZ951

Yup Nissan GTI-R. Basically a hell of a 4WD rocket with oil circulation issues. The GTI-R and Toyota 20V both came with individual TB from stock. The 20V is a smaller size though... It wont be hard to do, given the experience and access to tools, its just if its worth the effort...

Duke

Anyone got the port to port measurments?

BTW speaking of E30...here's a "decent" manifold (no ITB though)

J Chen

Now that is a properly designed intake.
Jost look at the tapered runners.
Must cost a bomb Duke ?

NZ951

Damn thats sweet. I was not sure on a CF intake before, but damn thats nice...

J Chen

Too bad it's not made for our cars NZ.
Notice also how large the plenum
volume is ? This is what's lacking in our
manifold.

NZ951

I am not sure of the design options when considering the TB and IC and Turbo position... I really need to sit down with the boys and nut it out. Runner length, and plenum volume need to be calculated, and I dont know what the measurements should be... ideas anyone?

J Chen

Ideal runner lenght should be no less than
15 inches measured from intake valve seat
to the throat of the TB. Plenum volume 2-3
litres. Talk to your boys & let me know what
they come up with ?

NZ951

Ok, had a chat with the boys. Looked at SR20 GTI-R and 20V Toyota TB's.

Basically with the AOS being so close to the intake manifold, its thought that the intake design will be much worse than the factory one.

The 20V could be an option and cut the stock manifold to maintian the injector ports and make a new plenum. This way each TB can be lined up perfectly straight as each TB can be seperated and new linkages made... I think this is the best option.

The SR20 units 1 and 4 dont line up but 2 and 3 do. This would mean that 1 and 4 would be somewhat angled in. The stock plenum looks like it may fit, but its very deep.

Looking at the designs of aftermarket intakes, they are made poorly because of the restriction of the AOS position. See attached picture, clearly the manifold is cut short because of the AOS position.

There has been talk of simulating the proposed designs... which will likely happen.

NOW... to get the benefits of a DECENT intake and correct runner length and plenum volume and shape, the AOS needs to be addressed. So I was thinking, why not cut a top section off it, and plastic weld in an "S" type shape to move it closer to the fire wall? Then we have huge potential for a good manifold. Thoughts anyone?

This weekend is another dyno run, then wasted spark is going in, then another dyno run. So when the intake is off we can examine the SR20 plenum.

J Chen

Hi NZ,
What's the ID of the 20V TB's ?
Strange, why would 2 & 3 line up
while 1 & 4 can't. The bore distance
should be equal. Yes cutting the AOS
would be a good idea. As far as I'm concern
all aftermarket manifolds have runners that's too
short.

NZ951

Yeah the distance from the TB's is not the same on the SR20. The gap between 1 and 2, and 3 and 4 are shorter than between 2 and 3. We lined it up and thats how it is! That wont be a problem on the 20v TB's as they can be detached. The ID is about 43mm on the 20v. Yeah the runners are way to short and the plenum not well designed at all. Does anyone have a spare AOS handy?

UK952

Would you need to plastiweld the AOS? could you cut it and use a silicon hose? (assuming the section is round)
Tony

J Chen

43mm ID is small NZ.

NZ951

That would be more difficult I think, the AOS reduces and I dont think a hose would come in the required size and shape. Plasticweld would be much more neat. I just cant believe a tuner making intakes has not thought of it, maybe there is something I am missing...

NZ951

Whats the stock effective ID? It wont be far off??? Also, can they be bored?

Skunk Workz

Stock size at the manifold flange is about 40 mm...not much bigger needed.