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911st 911st is offline
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Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
A C2T is a great car out of the box.

The stock K27 7200 turbo is good unit. Taking the cat/muffler off, keeping the stock secondary muffler and setting the boost for .9 makes for a strong runner making about 360hp.

Cams are a work around for the real issue which is the small intake ports that were required to help with air fuel mixing on CIS to better meet smog requirements.

Going to an SC or S2 (C2) cam lowers the effective compression ratio and can hurt pre boost performance to gain on boost performance. This is well matched with a bigger turbo that runs more efficiently up top but that also hurts low end. More boost is not the answer. The more efficient turbo heats the compressed air less and makes more power. Note that the K27-7200 can start to run out of boost up top. That is not a big deal as there is not enoght fuel to support much more anyway with out a fueling strategy.

The S2 had bigger ports, C2 cams, and a special turbo that had the same compressor wheel as the K27-7200 but had a bigger hot side turbine wheel to lower back pressure and heat for track events. It also had a bigger core installed in the inter-cooler.

If one wants to go to cams the best approach is to bump the compression a little by shaving the heads 1mm, and open up the intake ports. The bump in compression helps make up for the loss of effective compression with the more aggressive cams. (A part of the 94 3.6 Turbos magic comes from its higher compression.)

Add to that a cat bypass on the C2T that keeps the stock muffler in the right fender and set boost to .9 bar and you have a great running car.

The secret to better throttle response lies in the WUR. Look into a vacuum sensing WUR (Rice Fueler). This instantly reduces control pressure with acceleration allowing the metering plate to move quicker. I did this electronically with my C2T with a frequency valve and a special controller I plumbed around the WUR and it made for a lot better throttle response.

If I ever get another C2T I will just put on the cat bypas, set the boost at .9bar, mod the WUR and put a set of C4 normal gears in place of 2-5.

This would make it a rocket ship.
Old 12-01-2008, 10:01 PM
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