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911st 911st is offline
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Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Turbo Exaust Theory

I read this info years ago and just came across it again.


Notes that at 400hp+ a 3.5" tube is best.

Also notes problems to avoid with a turbo exhaust design. One might want to avoid cheated turns where a proper radius is not used to match the turbo with the muffler or crush- bent tubes. Also, any unnecessary turns like coming back under the turbo to exit the drivers side.

300hp likes 3" tube and is near its limit at 400hp.

Also discusses the advantage of a low back pressure exhaust system to improve boost response.

I am thinking a best practices 930 muffler would have a CNC machined tapered bend that transitions up to a 3.25"- 3.5" straight through muffler that exits the passenger side with a long radius and minimum turn tail pipe.

Years ago I had a popular aftermarket muffler that actually overlaped the turbo exaust opening adding restriction.

Old 03-04-2009, 05:01 PM
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