I'm looking to replace the I-pipe and the tailpipes on my car to 2.5 in pipes. I am willing to loose(or move up higher in the RPM range) a little torque. The 2.5in pipes would give me better overall power, right?

 

2.5 in. is fine...


I have a 2.75in with stock z28 muffler sounds mean and mellow, rumbles at idle and gets louder through the RPMs


and I got it for free jsut hasd to pay for installation... Big gain over stock i-pipe and not a loss in down low power at all...

Just avoid a big I-pipe and super high flow muffler, those can get a little to flow but still are not too bad.

 

So a Flowmaster muffler and 2.5 in pipe will flow about the same as a stock Z muffler with 2.75 pipe, right? With the couple mods I have now I got a really big gain so I'm hoping a bigger I-pipe will help 2nd gear out, which is where my car really struggles.

 

Flowmaster mufflers will flow better than stock but a 2.5" w/ Flowmaster WILL NOT outflow a 2.75" stock Z exhaust set up.

I would go for 2.75"...

 

But the in/out on the muffler is 2.5. If I go any bigger than that the mufffler will just restrict it down to 2.5 again, right?

 

I ran a 15.9 with my stock z28 catback, which I have never done before with a 100% legal exhaust.

 

...the in/out on the muffler is 2.5. If I go any bigger than that the mufffler will just restrict it down to 2.5 again, right?