( 
)Ever wonder why stock exhaust is only 40-50mm/1.5-2"?
Ever wonder why performance catback systems for compact cars are not usually bigger than 60mm/2.35"?
A 2.2 barely see's 230 CFM at 6,000 rpm.
Based on gas law and thermal dynamics, 99% of piping that you see on "tuners" cars is not needed.
the demand for 3" piping isn't until upwards of 600+ HP on an N/A car.
60mm/2.25" should be used up to 300bhp
65mm/2.5" should be used up to 450bhp
70mm/2.75" should be used up to 600bhp
75mm/3" should be used up to 750bhp
dont kill your bottom end cause you wana go right with a 3" exhaust. read this guide and then decide on your exhaust inlet size.
p.s. Turbo cars are different and do require Huge exhaust systems depending on the size of the turbo. some turbos require 3.5 and 4" exhaust's.
the guide above is for cfm and can be used for the correct exhaust size per turbo as well.
Ever wonder why performance catback systems for compact cars are not usually bigger than 60mm/2.35"?
A 2.2 barely see's 230 CFM at 6,000 rpm.
Based on gas law and thermal dynamics, 99% of piping that you see on "tuners" cars is not needed.
the demand for 3" piping isn't until upwards of 600+ HP on an N/A car.
60mm/2.25" should be used up to 300bhp
65mm/2.5" should be used up to 450bhp
70mm/2.75" should be used up to 600bhp
75mm/3" should be used up to 750bhp
dont kill your bottom end cause you wana go right with a 3" exhaust. read this guide and then decide on your exhaust inlet size.
p.s. Turbo cars are different and do require Huge exhaust systems depending on the size of the turbo. some turbos require 3.5 and 4" exhaust's.
the guide above is for cfm and can be used for the correct exhaust size per turbo as well.
Guide created: 07/28/07 (updated 10/21/08)
Thank you for voting. If your vote meets our 
