I want to upgrade the exhaust, but since I am not changing the turbo down pipe what benifits would I get from deleting the cat and straight piping the stock 3.5" system? Has anyone done and did it set any codes, I know the finger stick would prevent the code. I plan on adding gauges and tuning in the next few months, but since it is still exhaling throught the same down pipe a larger system would slow the velocity of exaust, right? If I am the stock system that has been straight piped should lower EGT's and lower back pressure? I have stainless 3.5" pipe and access to a pipe machine capable of bending it, any help input would be appreciated.

Rob

thats a good question i was wondering the same thing.

killing the cat will help E.G.T's

I put a system on my new 06 LBZ that is 4 inch front pipe and goes to 5 inch right below the passenger seat. I removed the cat. After 6000 miles it started setting P0401 (EGR Code). I went to PPE web site and have an email sent to them to ask them about their compenent that tricks the PCM also a block off plate for the EGR system. It does run better and seems to spool up faster on the turbo. I will keep you informed on what they say about the new computer and block off plate

I cut my cat and muf. It dropped my EGT about 20 degrees average, nothing much. It does spool up a lot faster and the sound is incredible!