Originally posted by chezterr:
Contoursvt11 makes a good point.

There is a HUGE difference between 2.25" OD and 2.25" ID...


There is Not a huge difference at all, but then again I have not seen any aftermarket that was 2.25" I.D.
BTW - We are talking ~5% more flow area if it's very thick piping (I.E. negligable) Probably less in actuality. (3-4%)

The jump from 2.25" O.D. to 2.5" O.D. is around 25% more flow area.

The jump from 2.25" O.D. to Dual 2" I.D. is over 65% more flow area.

Even the jump from 2.5" I.D. to Dual 2" I.D. is around 30% more flow area.

All those Aftermarket setups I have seen are 2.25" O.D. just like the stock single piping.


My guess is people forget the thickness of typical SS piping is greater then standard aluminized. This way it does not crack from heat cycling like SS is prone to do. (I.E. another reason why it lasts 2-3 times as long, but then again weighs 2-3 times as much)

2000 SVT #674 13.47 @ 102 - All Motor! It was not broke; Yet I fixed it anyway.