I have the new KW kit and plan on using the stock exhaust / cat. I expect to limit boost to about 11 psi and expect to make upper 300s whp on 91 octane.

Are there people out there boosted to about this level that use the stock cat? If so, do you track the car? How long have you had this setup?

 

Not interested in running a test pipe?

 

Interested in this too. Running a test pipe is not an option for me either .

 

I have been running my oem cat and exhaust with my supercharger for 50k now . Still no issues . I think allot of it depends on the tune on how rich the car is . Some people on this board have had bad luck running the oem cat and others like my self have been fine . I am running a Vortech supercharger with 12 psi and an Aem ems . This combo nets me around 400whp . The cat is killing some power though .