Post your gains at the track with a cutout everyone, thanks

 

I have a solid 2 tenths off my time with my y-pipe located pre cat cut-out. I'm going to ditch the stock headers and y-pipe this year though as I already have a cat-back.

Closed = 15.59x-15.6xx vs 15.4xx consistently open.

I actually pulled a decent 15.47 @ 91 mph first time open.

Best is a 15.414 @ 89 mph.

 

nice gain, it would be interesting to see what you would gain with headers and a high flow cat open vs. closed. let us know

 

The cat is a hiflow dynomax cat, I lost the stock one a long time ago. The cut out is a good test of how the cat, no matter how "free flow" is a real restriction.

 

Don't you mean an exhaust system? Cause last time i checked my cat was connected to the rest of my exhaust and most race cars have no exhaust.