The wider exhaust may help your upper powerband but with a setup like that, it is probably going to kill your low end. I don't see a reason for a thicker exhaust than the 60mm piping that major manufacturers offer. It isn't like you are running some high lift cams or forced induction that REQUIRE larger exhausts for bigger power gains.

 

170 whp, is that a butt dyno assessment.
What's your power goal?



It really depends on how far you want to build up your car. I'd recommend a 2.5' exhaust system to someone who's planning on boring to 2.0L and going with big lift, high duration cams. I've read an article on team-integra that states a 2.25' exhaust system can support up to 210HP @ the flywheel (about 180-185 whp).

 

Well last year I gynoed 166whp without the clutch and flywheel so Im making a educated guess that it should be at the minimum of 170 now.


Around 180whp and a 13 second car.




I do plan on going with skunk2 Stage 1s OR CTRs this year

 

if you get a 2.5'' exhaust you should get a header with a matching collector and a matching cat.

 

I would leave it at 60mm. I've always gone by this guide from Team-Integra when choosing an exhaust size.

2-1/4" up to 210HP @ the flywheel (about 180-185 whp)

2-3/8" (60mm) up to 235HP @ the flywheel (about 200-207 whp)

2-1/2" up to 265HP @ the flywheel (about 225-235 whp)

2-3/4" up to 325HP @ the flywheel (about 275-285 whp)

3" big for big HP (Forced Induction: > 275 whp)

 

I already have a DC JDM ITR Header and Car sound 2.5 cat so im actually bottle necking