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      03-14-2013, 12:10 PM   #7

Drives: m3
Join Date: Feb 2013
Location: NYC

iTrader: (0)

Originally Posted by Andrew@ActiveAutowerke View Post
Our X-pipe is 2.5 inches measure from the outside of the pipe. The inside measurement is 2.3 inch.

We made a custom 3 inch x-pipe for a customers race car per his request and lost power. Bigger is not always better...
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?