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Thierry25 Thierry25 is offline
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Join Date: Feb 2009
Location: FRANCE (Besanšon)
Posts: 310
Originally Posted by RarlyL8 View Post
My muffler and waste gate dump are good for 12whp on a stock 300HP Euro 930 engine. The baseline engine I tested used the stock early Euro muffler. I also tested late USA 930s with CAT and found similar results. It is interesting to note that 0.75bar was maintained in both situations. I assumed boost may increase a little due to lack of back pressure on the waste gate but that did not occur on these stock cars. Any extra boost would of course scew the power number.
That is only a tiny part of the story. The engine revs quicker, more freely, and boost comes a few hundred rpm sooner. You also get all those great turbo sounds that the stock system hides. The driving experience is transformed.
A straight through non-restrictive and non-baffled muffler is a must-do before looking at performance enhancements. The turbo must not have back pressure.

Thanks for the inputs.

I am not sure I well explained the things. I am sure to understand your exact meaning either.... ah don't blame me ... my poor english !

Actually, I have a cat by pass on the turbo output + sport muffler. So on this exhaust output, I share completely your opinion !!! less restriction = more power and more spools at earlier RPM

My meaning concerns the behaviour on the Wastegate muffler only. Actually on C2T the small stock wastegate exhaust include the catalyst which provide an high restriction. Most of people thinks that a free flow wastegate exhaust doesn't bring any improvment... Personnaly, I start to think this wastegate exhaust restriction also reduce the total exhaust flow efficiency. Thus, I think this restriction is also increasing the back pressure.

Do you share this opinion ?
965 C2T / 1991 3.3 TURBO
Old 01-05-2010, 10:33 AM
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