Pelican Parts Forums - Trying to make my carrera 3.2 FASTER!

Pelican Parts Forums (http://forums.pelicanparts.com/)

- Porsche 911 Technical Forum (http://forums.pelicanparts.com/porsche-911-technical-forum/)

- - Trying to make my carrera 3.2 FASTER! (http://forums.pelicanparts.com/porsche-911-technical-forum/430635-trying-make-my-carrera-3-2-faster.html)

The 930's run CIS injection that has a large metal metering plate and arm that it in the way of intake air path. It takes some effort to move it with changes in air flow which contributes to lag.

With a turbo conversion on a Carrera with EFI there is not that restriction.

Combine that with a more modern turbo design that uses a smallist hot side and a larger compressor wheel and the boost starts coming on earlier and builds a bit more gradually.

Add to this a higher compression motor (7 to 1 for a 930 -- 9.3 to 1 on a Carrera.) and there is more pre boost HP and power almost comes in like a big normally aspirated motor.

You have an option to use a K27-7200 from a 91-94 C2 Turbo or similarly sized turbo that has a smaller compressor wheel. This dose not have as much windage or mass and it allows the turbo to spool up to full boost faster and comes in harder. Something like boost onset at 3k and full boost at 3.4k compared to something like onset at 3k and full boost at 3.8k rpms. However, power starts to platu before red line compared to the larger compressor wheel and it is not as efficient at high rpm so it heats the compressed air a bit more which hurts Hp some..

My self, I like the smaller turbo for street. It dose not give quite the HP bragging rights but comes in faster and harder.

Just my opinion.

A race turbo, should have a larger hot side to reduce back pressure drag and reduce heat in the exhaust system but boost will come in latter.

This is what Porsche did on 92 with there special S2 turbos based on the C2T as built by Andial. The basically took a K27-7200 and added a larger compressor wheel. This along with a large inter cooler core, C2/4 cams, and larger ports, .9bar boost made for more HP which was about the most the stock CIS could support.

I took my former RSA to the drag strip once, ran a 13.8. Drag racing it made me feel dirty. Oddly enough I went with a friend who had a 04 350z. My RSA beat that car without a problem. That same RSA would have trouble passing late 80's 911's in the main straight at Road America.

Quote:

spence88mph -

OK, now I'm confused. You're currently running without an intercooler, as you don't want to mount a wing, but you're signature line says M491. An M491 without a wing?

Also, are you running the stock clutch?

I'm asking because I'm seriously considering doing this mod to my '87, although I'm also keeping my eye out for a good deal on a 930.

FYI, my view of turbo "switch like" performance is also based on my dd - a late 90's Saab turbo, which runs 1.08 bar and comes on rather suddenly and entertainingly at about 2800 - 3000 rpm, but off boost is about what one would expect for a 4 cyl, 9.2:1, dohc motor in a 1370 Kg car.

Yep you have every right to be confused, it's an M491 but was ordered without the spoiler, it was delivered with the big turbo spoiler in a box so I have that, it's never been mounted. Stock clutch yep.

There's some pics in this thread and some youtubes of the car:

http://forums.pelicanparts.com/porsche-911-technical-forum/174562-how-does-widebody-carrera-look-without-spoiler-3.html

I almost bought a factory Cab "Turbo Look" with the spoiler delete option.

What was interesting about that one was the special trim piece under the front bumper in-place of a spoiler.

Passed on it cause it just seemed slow. (California car & extra weight.)