Hey all,

I'm new here. I have a 1990 Celica track car with a 4AGE Silvertop swapped into it. I got the car from a friend who raced the car for a long time with the 4AFE in it. He swapped in the ST, but was unable to finish it due to time constraints. Now I have it and I am wrapping it up. I plan to use it for Autox and HPDE events.

I found a hole in the intake plenum. The small vacuum nipple on the back of it looks like it was broken off when the motor was originally pulled. Rather than weld it up, I was looking into an upgrade that was smaller and would clean up the engine bay a bit. I found this plenum on eBay and was curious if anyone had any input on it. I did a search but didn't find anything worthwhile.

http://www.ebay.com/itm/OBX-Turbo-Plenu ... ae&vxp=mtr



Here is the car.

The design is about as bad as you could get for a plenum. It's way too narrow and airflow will be compromised.
It looks okay though.

Welcome to club4AG

Rulez wrote:I found this plenum on eBay and was curious if anyone had any input on it.

The OBX plenum you found is for turbo applications, and will not be
helpful for a N.A. car. As it happens the factory plenum actually works
quite well, and of course it has the right size connection for the AFM.

There are aftermarket plenums around... along these lines...



Only they are designed to work best with heavily modified engines with
standalone ECU's. Then the engine can be tuned to take advantage of
the revised intake and conversion to MAP sensing.

Cheers... jondee86

Thanks for the input guys! I'll just repair the stock plenum then. Eventually I'd like to go standalone and eliminate the MAF altogether. Better to just invest in that I suppose.

jondee86 wrote:Welcome to club4AG

Rulez wrote:I found this plenum on eBay and was curious if anyone had any input on it.

The OBX plenum you found is for turbo applications,

IMO it's just as awful for turbo applications for the same reasons you would expect it to be for NA.

I've been looking at this same hunk of metal myself, trying to decide if it was any better than the one I fabbed from steel. At least I considered how air flows! It's been quite a challenge to find a suitable manifold for my application. Anyone know of any out there for boost applications, other than this junk? At this point I'm considering buying a set of stacks and building a manifold from scratch, but aluminum is an area I haven't gotten in to yet.

The MRP plenum (shown in the pic I posted above) is designed for
boost. The baseplate is CNC'd out of 10 or 12mm plate (can't remember
which right now0 with an o-ring groove for sealing. If you are looking
to boost 30psi you will need something like that

Cheers... jondee86

Very nice intake too. I'm afraid it would be too wide at the bottom with the supercharger top bracket and coolant pipe in the way. I'll need something that spaces off from the ITBs just enough for bolts to go in. The search goes on!

moncharleskey wrote:Very nice intake too. I'm afraid it would be too wide at the bottom with the supercharger top bracket and coolant pipe in the way. I'll need something that spaces off from the ITBs just enough for bolts to go in. The search goes on!

I can design and make anything you might want but we aren't talking about OBX price range anymore.




You mention supercharger brackets. What exactly are you doing? Supercharged 20v?

I'm running a 7A block, 20v ST head, and JDM sc12 with 175mm T3 pulley. Loads of other stuff in there too but as far as being applicable to the intake, it's in an MR2 and while my heavy steel one holds the boost, I can't shut the deck lid! I thought about hitting you up to build me one, so shoot me an email if you want to get together on it, this username at Gmail.

moncharleskey wrote:I'm running a 7A block, 20v ST head, and JDM sc12 with 175mm T3 pulley.

I'm not the boost guy... but even I know that poor SC12 is having a tough time... it barely is sufficient for a stock 4AG, now you have much more engine breathing... and still the small charger....

SC14 at the very minimum... but I'd be looking for more volume... look @ Eaton

Now as to running a turbo instead of a S/C... sized right(the turbo), with a good turbo manifold...



and you can make metric tonnes of power ...unfortunately these will fit as well as your intake does...

If you can find a Nissan GTiR intake plenum you could get SamQ's adaptor, they aren't easy find though:
http://www.sq-engineering.com/upgrade-p ... amber.html