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System with cats or no cats?

1.5K views 2 replies 3 participants last post by  K-Man S  
#1 ·
I have been looking for a good exhaust system and I have found that they are a bit cheaper without the cats. Aside from them not being emission legal, would not having them provide a significant difference in performance v.s. with cats? If so, how many more ponys and torque. Anyone know ?
 
#2 ·
whitebluetoy you should do a search on 'exhaust'. it is discussed in length here.


Cayman S has 4 cats and most mods delete the last 2 while maintaining the front 2 (headers). this will pass emission for most states with the exception of CA.
 
#3 ·
mt647,


It may pass California emissions testing as well, but the only way to know is to have one actually tested. I concur this has been discussed in details elsewhere. The only one that I know of that has been tested separately was the B&B exhaust and if I recall correctly headers gave an 8hp gain and their cat-back a 9hp gain so about even. Other systems may vary from those ratios depending upon design.