I have been trying to find a actual discussion on is it worth going to a full 3.5" exhaust system. Seems like plenty of people are making great power with 3" exhausts. My only concern is the clearance is drastically reduced on a slightly lowered car.


Thoughts?

 

i'd say in 90% of cases it is over kill.
Over 500WHP it's worth it if your trying to squeeze out everything you possibly can but using a 3" will not hold you back much and keep the sound level WAY down. (you'll see 20-30WHP removing a 3" exhaust/muffler on a 600HP+ turbo engine. IMO if you can expand the exhaust pipe smoothly (bigger by 10-20%) than the turbine housing outlet it will flow the best for given turbine/housing size.

 

Ben Lin from the Gears & Gasoline YouTube channel went from a 3" to 3.5" exhaust and gained about 40whp. It should be noted that the 3" system was using a high-flow cat, and the 3.5" was not. They talk about the dyno numbers at about 9:30 into the video.

 

The car makes a huge difference lol

Dont need 3.5 until over 800whp or so.