I gutted my cat over X-Mas, and there was a cut in bottom end torque, but the gain in top end is nice! I had to drop the whole exhaust to get the cat off! It is great!

 

You realize what you're proposing breaks at least a dozen state emission laws and a big federal one...



-Ted

 

DON'T GUT YOUR CAT, give it to me if its in good shape, Ill even send you a staight pipe.

 

Emissions laws...Who cares! They don't do emissions tests in my county here in Texas! Sorry mother nature, speed is more important!!!

 

I dont think it is worth it for the minimal HP gains. You are creating more turbulance in your exhaust system too. I gutted my cat in my TII, and I regret it. Should have just gotten a straight pipe made for 30 bucks.

 

How lowd it running no cats with the OEM mufflers anyway?

I like this idea better

 

Get a straght pipe instead, you'd have gotten more power, and you just trashed a really expensive freakin cat for the RX-7!
I wish I never gutted mine, I ended up getting a straight pipe a month later, and then I had to get a cat to pass emmisions- a standerd cat on these cars won't do very well with emmisions and doesn't last long.
I don't like the tinny sound you get through the walls of the cat either.
The overall sound with the stock mufflers and gutted cat is pretty metallic, but not loud compared to aftermarket systems, just not very low pitched either.

 

not if its clogged. or if you have a turbo

 

No offense, but I completely disagree... True, the transition to the large volume of the cat chamber then back to the pipe at the back isn't the best way to mainain exhaust velocity, but it does dampen output pulses somewhat, and reduces reversion pulses, smoothing things a tad.
I will give you my car if you can show me that even a brand new cat flows better than a gutted one!!!!
A gutted cat is not as good as a straight pipe, but without the restrictive catalytic brick inside it flows a hell of a lot better, with MUCH less backpressure, than a complete one.

Why do you think those with 86-88's have so much issues with activating their backpressure dependant 6 ports if they gut their cats? Lower backpressure.

Regardless of the point i'm making, - don't gut your expensive cats, get a pipe for 30 bucks!! You'll thank yourself.