I'm in the process of building a car for NHRA's Sport FWD class. NHRA wants
us to run a full exhaust system with muffler in this class.

The question is size, I know turbo's hate any kind of backpressure so how big
do I need to go? The engine is a 2.5 liter Mopar, T66 turbo, air/water IC, power
should be in the 500-600 range with torque in the 500 area. Oh, plus the shot of
NO2.

Is 3" large enough, how about muffler, was thinking Borla.

Thanks Steve

 

I run 3 inch on my 1.8, everyone tells me the go as big as you can on exhaust. Since you setup sounds a little more heavy duty than mine. I would go 3.5 but then again I would get some more opinions too.

 

The bigger you can fit under there the better...