This maybe a bit of a noob question... but I am going to ask anyway...

I am looking at doing a 2.5" Cat-back exhaust. I am pretty much sold on the fact that I don't need 3" all the way back because I'm not putting out enough HP and i could potentially loose bottem end HP. I want to change the DP too. I am looking at the catted Hahn, but my question is, will it matter if thats 3" and the exhaust is 2.5"? Should I stick with the stock DP? or should I try and find a 2.5" DP with a high flow cat?

I guess with my basic knowledge, if the DP is 3" and the exhaust is 2.5" it will create a bottleneck effect and will not flow well. Thanks for the input...

 

This is not totally true. There are more important things in an exhaust system then just flow (like exhaust gas velocity).

Your car already comes with a pretty good 2.5" catback exhaust from the factory. The biggest bottle neck in the SS/TC's exhaust system is the downpipe. Replace that, and leave the stock catback. No need to replace it with an aftermarket 2.5" catback, unless you want a louder sounding exhaust.

 

I thought it was a 2.25"?

 

Thanks..

on the TC its a 2/5". And yeah, I wanted something louder and more aggressive.

 

oh, tc gotcha. me<reading.

 

The SS/SC has a 2.5" catback as well, but it necks down to 2.25" over the rear axle to the muffler. The SS/TC's is 2.5" all the way back.

 

I doubt you would lose any bottom end horse power. The back pressure all comes from the turbo, anything behind that is just lost hp. Go 3 inch if your gonna waste your money (unless you go bigger turbo there is little to no gains from anything after the down pipe. Or an I infiniboost tune might put you almost to where you need bigger exhaust. Almost... If your looking for louder muffler resonator delete and a catless downpipe.