I am bringing my car in on Friday to MTI to get heads/cam and a few more boltons.
I have Jet hot headers, Jet hot catted y and Loudmouth.

Do you think the cats will hurt my dyno numbers much?

How do they flow?

If I pull them I will have to put in the dynomax muffler in place of my resonator on the LM at a later date. It is loud now and I love the sound. I cant imagine it any louder... BUT....HP & TORQUE is MY NUMBER 1 PRIORITY. If the dif is only say 5 hp i guess I will leave them in but more than that and they have to say bye bye.

 

I would say to remove them, but that is also because I am anti-cat. I think the exhaust note is far more appealing without cats, using the proper mufflers to rid youself of rasp and un-tuned exhaust note. Cats give any system too "mellow" of a note, IMO.

Also, cams don't sound as nice (less lope) through cats.

 

They are a PITA to get out!!! I'd just leave them on to see how much you actually dyno.

 

Understand on the PITA part. The tolerences are so close between the sleeve they fit in and the cat that I put a bit of silicone lube on them just to get them to slide in when they were new. I imagine they are pretty siezed up by now.

 

I also had the two little cut pieces mounted in the ypipe when I took the cats off, decided I didn't like the sound. So after 2 days of driving the car maybe 30 miles tops I wanted to take them off, well those two little bypass pieces are in a land fill somewhere because I literally had to beat the crap out of them to get them out. They were all mangled and bent up, so they were essentially useless