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Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
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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. |
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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.
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-Mark B. Hardware Store Engineer 1988 911 - 3.6 1999 SL500 - Gone 1995 M3 - LS2 - Gone 1993 RS America - Gone |
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Join Date: Jan 2007
Location: Melbourne, Australia
Posts: 1,581
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Quote:
There's some pics in this thread and some youtubes of the car: How does a widebody carrera look without a spoiler?
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'89 911 M491+Turbo '89 944 Turbo '88 928S4 '18 C63S Coupe |
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Location: Sacramento
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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.) |
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