Twofer

87 N/A Luxury model, 135k mi, stock exhast system.

I noticed an exhaust leak a while ago and figured I'd get around to fixing it today. Previously, to determine where the exhaust leak was, I ran my hand underneath the exhaust system with the car running. Between the Main Cat and Precat #2, I could feel air coming out to match the RPM and low RPM cold stuttering. I also noticed there was a hole in the heat sheild underneath the joint between the Precat #2 and Main Cat.

I ordered 2 exhaust gaskets from Mazdatrix and pulled everything apart today.

I first replaced the Main Cat to Y-Pipe gasket, then moved on to the Precat 2 to Main Cat gasket. I couldn't get the bolts off so I pulled the whole thing between the Exhaust manifold and the Y-Pipe. With the cats out of the car, it's nice and easy to get a 6' cheater bar on it.

I cleaned everything up with a steel brush, then some steel wool, and I was planning to bolt it back together and reinstall it tomorrow. Before I do, I figured I'd let you guys have a look at some of the pictures and make any suggestions. I'm not really sure what a 20 year old exhaust system should look like, so please have a look at the pictures for anything out of the ordinary.

I'm replacing the gaskets between the (Y-Pipe and Main Cat) and between the (Main Cat and Precat 2). I also cleaned the open mating surfaces with a steel brush and steel wool. I was going to put it back together with some anti-seize on the bolts.

Also I'd kinda like to get new bolts, if easy enough.

Edit: Where does the Precat 2 hanger hook to? I didn't see anywhere on my car... the whole thing was just held up between the Y-Pipe and Exhaust manifold. (Possible cause of the problem?)

Thanks!

staticguitar313

iTrader: (2)

Bonez superflo cat and borla or racingbeat catback <<< solves all problems and you get a sexy exhaust note

Omixeo

iTrader: (1)

Also a header would get rid of those pre-cats. Alternatively to the pre-cats, you can get a "downpipe" from racingbeat and i think theres another compant that makes one. I forget who made the one that was on my car.

mikaz

I highly reccomend replacing all that stuff with a bonez presilencer and high flow cat. It will bolt up to everything with ease.

mazdaverx713b

iTrader: (91)

or just build an exhaust with parts from racing beat. the bolts look like they're in excellent condition!!! you are very very lucky there dude. most i've come across are completely rotten and unuseable.

Twofer

I gotta have it CA emissions legal, so there has to be a cat in there somewhere.

I was thinking replacing the exhaust with an aftermarket setup, but I don't really want to spend the money right now.

I forgot about the Bonez products. I was reading on http://rx7.com/store/rx7/fcexhaust.html that their presilencer / hiflow cat bolt up in place of the stock cats. (Which is exactly what you guys suggested.)

Also I don't want to spend too much on this car, since there's the whole argument about "How to get more power out of a NA" which always results in "Buy a turbo car."

I think for now I'll stick the stocker back in there, but if it pisses me off in the future, I'll go with the bonez system.

Thanks guys!

Twofer

Well, I put everything back together and it still leaks. After a little more inspection, it looks like there's a hole in the front right corner of the main cat, with exhaust blasting out of it.



F**K.

Can you get that welded shut, or would that do more damage than good?

john ward

iTrader: (7)

usually if it gets like that the metal is too thin and deteriorating to weld but hey give it a shot if you want. i highly recommend racing beat header. youll love it