I recently purchased a 2002 Silverado that currently has an On3 turbo kit with a 3 inch downpipe to 3.5" exhaust and muffler. I have a KB Racing turbo kit ordered which will have a 4" downpipe. My question is can I just use the 3.5" exhaust/muffler after the 4" DP or will that restrict it? I figured open DP will be too loud for the street but I don't know, as I've never had one. Just looking for any advice or recommendations on turbo exhaust after the DP. Thanks.

 

Should be just fine going back down to the 3.5 exhaust after the downpipe.

A full 4in exhaust would be something to look into if you plan to really push that motor and make some serious horsepower.

 

Will the power difference really be that significant going from 4" DP to 3.5" exhaust vs 4" exhaust?

 

I'm sure at some horsepower level it would perhaps be choking it.

But I doubt most people would feel any difference in the butt dyno by going straight to a 4in full exhaust when they don't need that much flow. Also 4in exhaust is going to be loud.

 

I wouldn't bother changing it. 3" is good enough to support 700

 

My 5.3 lost 50 HP with my cutout closed......... 3" DP, 3" all the way back to a straight through magnaflow.