Streetdaddy

Looking at a possible rebuild in the future. I see some have silver air intake manifold's. Are they spray painted or is this an aftermarket piece?

Sire

Do you mean the ones from Rothsport racing and FVD?

Streetdaddy

O boy... now i see how the rebuild price starts to go up!

Vandit

'89-mid 91 cars had aluminum intake plenums. Mid-'91 and onward had plastic plenums. They're supposed to flow the same but I think the plastic weighs less and is less prone to heat soak.

That FVD piece is modeled after the 3.8RS/RSR and has the throttle bodies at the bottom (individual) versus a single butterfly closer to the start of the intake tract. From what I've read, the powerband is not great for the street.

Lots of other builds use the GT3 plenum and ITBs. Magnus, Singer, Rothsport, etc. All those are GT3 plenums.

Streetdaddy

Thanks Vandit. That explains it. Those Singer plenums are so gorgeous. But I guess i'll have to settle for a powdercoated engine fan !

cobalt

Nice but the castings are really quite rough. Looks like too much moisture in their sand mix and the parting lines are a mess. If i were spending that much I would expect better.

Steve Weiner-Rennsport Systems

The ITB's as used under a plenum, stock or GT3, works VERY well with instant throttle response; something you never get with any single-throttle intake system.

As an example, we did a stock 964 with ITB's under the OEM plastic plenum and a Webcam 20/21 (VERY mild) with near stock exhaust (G-pipe & cat bypass). This made just under 300 BHP with no other changes and is a ton of fun to drive.

Jjm4life

Stock Ecu?

Goughary

Steve can that unit be bolted into an otherwise stock motor and run well?

Vandit

It's basically this setup (964 plenum over ITBs). Looks like it requires new engine management and all associated sensors. Kinda like the Specialist Components engine management kit that robt964 installed.

http://www.rothsport.com/Products/En...-Butterfly.htm

Steve Weiner-Rennsport Systems

Motec M84. The OEM Motronic cannot control an ITB system.

Steve Weiner-Rennsport Systems

With Motec, yes indeed as thats exactly what we did.

Jjm4life

Thanks Steve. Not to go too far off on a range meter here, but on the topic of Ecu, is there a reason motec seems to be the "go to" Ecu solution vs aem?

Talat

This is what I'll be doing shortly - Rothsport EFI with AEM Infinity. Basically the same setup as the Bisimoto 911R. Went with AEM since it's the only ECU with knock control within my (increasingly out of control) budget. May add cams but not sure yet. Will start a thread once the work starts - I'm hoping to do a before and after dyno run.

Steve Weiner-Rennsport Systems

We prefer Motec for its quality, durability, and support. Naturally, software familiarity is everything and thats one of the key factors in choosing Engine Management. One of our employees has made the commitment learn this system and is a true wizard with Motec.

JMHO, there seems to be far more people around the country who know Motec more than any other racing Management system and thats a big advantage, depending on where you live.