I have a 93 5 speed RX7 twin turbo and I had recently put on a down pipe. What a difference in power. I was told not to put on a mid pipe becuase of the boost creep. How do we know if the OEM Cat is still functional? I had a 2000 prelude with a high flow converter installed. One day I found some type of honey comb looking thing coming out of my muffler. I took it to a muffler shop and the cat had blew out. That was odd for a 3 year old cat. The cat in my RX7 is oem. Do these cats over blow out? How do we know we have boost creep. Also wondering If I purchase a aftermarket exhaust with a silencer will that help on restrictions? Thanks

 

1. Get a boost gauge.

2. Repeat, get a boost gauge.

The cat normally doesn't fail unless the pre-cat fails and takes it out. If you actually read about boost creep, you would know if you had it....

Running a silencer on an aftermarket exhaust is pointless. It will flow less than the stock exhaust.

Repeat, get a boost gauge.

 

Simple test for your cat, if your idle is right, and your air pump works, stand behind your car for a few seconds, if you find your self choking or getting queezy, good chance your cat is bad.

I saw an obvious improvement with a good cat.

I take it you dont have emissions testing in regina?

 

DP is one of two of the most important mods. Add some header wrap or have it heatcoated to lessen underhood heat. The second/other mod, as rynberg indicated, is a boost gauge. Good advice on avoiding the midpipe.
If you have a good 10-8-10 boost pattern and your eyes aren't watering while standing behind the car, the cat is OK.