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      03-14-2013, 01:24 PM   #8
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Andrew@ActiveAutowerke's Avatar

Drives: 17 F80 M3 YASSS
Join Date: Dec 2011
Location: Miami Fl

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Originally Posted by M3takesNYC View Post
Oh I realize bigger is not always better. Its just not often you see aftermarket with smaller diameter than stock which to me can make sense to increase gas velocity but I will have to measure the stock as I am pretty sure its 2.75 inches OD.

I guess inner could be the same but doubt wall thikness would make up for a quarter of an inch difference in OD

Andrew any further thoughts on the purpose of the piping being smaller than stock from an engineering point of view or why it was chosen? Or is it alot of trial and error when making an xpipe like this?
Based on our previous dyno testing and the 2.5'' x-pipe is the best suited for the s65.
Like I said before a 3 inch pipe on the racer car made much less torque than the 2.5 that we currently sell. The size comparison between stock and our xpipe does not really line up do to the extreme restrictions of the cats.

We do however switch up to a 3 inch rear exhaust section for better flow.