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911st 911st is offline
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Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Per the article referenced above on Turbo Exhaust Theory, a 3" pipe's limit is about 400hp. That migh be with a front to back exhaust system where gasses cool, slow down, and create back pressure so I am not sure about us with our short exhaust path.

However, he also notes a taper just out of the turbine to I believe aid in flow and inhibit turbulence.

With many passing the 400fwhp range on our 930's, a 3.25 or 3.5" system may have some measurable benefit.

I really like what 125 shiftr did here to perfectly match his flange to the turbo and immediately transition to his chosen tube size.

My old B&B was not anywhere as well fit and had more of a step out of the turbo. Most of the builders seem to cheat this area.

Quote:
Originally Posted by 125shifter View Post
The exhaust flange was water cut to match the turbo housing, then the flange ID was taper machined to perfectly match the K27HF2's 2-3/8" outlet to the 2.5 to 3.5 tapered pipe. A short piece of 3.5" elbow is welded to the tapered pipe to point it to passenger side:


Old 03-08-2009, 08:10 AM
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