I'm looking at swapping out the cats for track events when I get the new Mustang, curious if anyone else has done this? Should be a fairly easy part to swap out, anyone ever dyno with/without cats?

I know the CEL will go on, not too concerned as I would only use this for track days. I had a cat-less setup on my old car for the track and it really opened up the top end.

I like a more free flowing exhaust setup for track days (and by track I mean road courses, not the drags), wondering if anyone else has experimented and found it worthwhile to do this!

 

Seems like a lot of work for a few horsepower. Why not get a higher flow full cat-back exhaust if you're that concerned about the peak hp?

 

I will likely eventually go full cat-back, but the main restriction in the exhaust is the cats... for $100 or so it's cheap and (I assume) quick to swap out for a couple day event.

And I'd rather spend the $500+ on track time than on a cat-back system when GT500 axle-back mufflers get me the sound I want. There are noise limitations at my local track, so near stock dB is what I try to go for...

 

With that check engine light the PCM will also think the cats are failing and start dumping extra fuel to compensate. You will lose power with that. You need a tune to adjust for that.

Not to mention that the cats aren't all that easy to remove. The bolts are kindof a pain in the butt to get to.