333pg333

Thought it about time to start a general thread on these rather than drown other people's threads.

I know there's a few of us tinkering around with these and have our theories. We're just putting one together today. Off to the dyno on Wednesday night so it will be interesting to see the basic differences.

Some of today's evolution:

Thom

That's an innovative design - no pesky TB or bothersome TPS.

V2Rocket

Send it to lart for polishing, that looks really nice already.

Big chamber! Are you running a hot cam to take advantage of higher RPM that the bigger plenum can handle?

And for a random question..how "tall" is the plenum (measuring the vertical plate the runners pass through)

Voith

I am only theorist for now, but why is the shape non-symetrical?

When air is cut off with intake valve it travels back where wave should bounce back in the venturi.

I will design my own intake too, but will follow this design:

rlm328

Voith,

What does keeping the shock wave off of the venturi do for you exactly?

Voith

Lowers engine volumetric efficiency and balance between cylinders? Or why do you think modern turbo race cars utilize this design?

Another nice example:

Raceboy

Made the double-plenum intake already back in 2005 for my Gulf 924:


Main plenum has tapered 20mm wide opening front to back and the 2nd plenum is welded onto the 1st. Works like a charm (270 hp @ 0.9 bars on 2litre 931 engine with stock cam).

Also made same intake for my 2.5 16v turbo, but with single throttle body.

333pg333

Yes, Spence we're running a pretty big cam. Very similar specs to the 2nd from top (8v) on the JME list. http://jonmilledgeengineering.com/CAMSHAFTS.html

Our setup is a very hurried build. It's like an elongated or flattened tapered plenum and once it's all in you will see that there are some packaging constraints that have had a direct effect on this intake. Not the be all and end all by any means but will be a good improvement over the stock intake we had. Will find out tomorrow night.

eman930

Dude your exhaust manifold is freaking insane

refresh951

Here is some documentation on my intake:

http://refresh951.com/Intake.htm

Dougs951S

Yours in the first intake I've seen that has an elbow like that leading into the plenum. Is your TB in basically the stock location? Do you worry that the elbow inlet is unevenly distributing air and causing the front and rear cylinder to run rich? I'm also using the ross machine racing stuff to build my 16v manifold, have not decided yet if I want to do what you did or run my intercooler piping in reverse and try to have what would normally be the inlet run into the front of the manifold. Then I could use one of their slick mustang or nissan TB adapter end plates, if I could figure out how to make the throttle cable work.

refresh951

Center feed has worked out fine, no issues at all. This was discussed in great detail in my 3.1L build thread TB is a Mustang unit and it is in the stock location. I like the idea of mounting the TB on the end of the plenum and reversing the IC pipes. A guy did this down in Mexico City IIRC, pics were on FB turbo page.

333pg333

Bit more of a follow up today. We were a bit 'ambitious' to attempt to build, install, and dyno this in a few days. Having to move or customise I/C pipe and our radiator expansion tank plus get a new custom throttle cable made up. Wish we'd had a few more weeks to do this all in. Might have been able to come up with a more efficient intake design too. However I have faith that this will still be good enough to allow this motor to finally breathe better.

Paulyy

That is a large plenum

333pg333

I'm confidant that on a track car that is at higher average rpms than a streeter will be ok with this. It's amazing how quick 'stuff' fills up under positive pressure. I guess think of those guys running turbos strapped down at the rear of the car.