Ok here is the deal I already have the 4" single out mufflex I was thinking of putting a Borla XR1 in place of the muffler with a header flange that way I can switch them out when needed. or

I also have a 3" flowmaster intermedite pipe I was thinking of putting the XR1 on this one and using it instead. I will be putting a header flange on it as well were I can switch to the SLP D/D muffler set up when I want it toned down a little.

So my question is this how much power would I loose with the 3" compared to the 4" ? My car has dynoed at 420 RWHP and a little over 400 rwtq thanks Mike H.

<small>[ July 04, 2002, 07:53 AM: Message edited by: Street Racer ]</small>

 

Is the 420/400 through closed exhaust or open?

 

I will probaby just buy a 3 1/2 and call it a day thanks for your input.

The HP and TQ numbers were through closed exhaust

 

With 420/400 through a 3", a 4" should show nice gains. I wouldn't think the trouble of upsizing to 3-1/2" would be worth the hassle & money for the minimal gains.

 

Biggest I personally messed with was a 3.5" Not so sure a 4" wouldn't be a major PITA for clearence.

 

it was through the 4" single outlet