Coming home from work tonight my car started rattling through the exhaust. Put the car in park and looked up the tailpipes and some grayish pebbly stuff comes vibrating out the exhaust, I'm guessing it's the catalyst. Anyone else have this happen? If I gut the cats (I have duals) how will it hurt the performance and will the car run with them gutted?

 

it will hurt it, badly. you will run rich as hell and have have no power. assuming you still have O2s that is

 

Still have all the O2's. This is pretty shatty news! I guess there is no way around running no Cats?

 

you have to have the O2s tuned out. save yourself some headache and buy some highflow metallic cats. thunderbolts are 110 plus shipping a pair

 

http://www.frozenboost.com/product_i...4dc11f7f10267a

 

I gutted my cat on my 95 Z and had no problems. It runs so much better with better performance and fuel mileage. Now that I think about it...... its still an OBD1 car. I guess that could be a big difference between your OBD2 and my OBD1 car. Is that the problem you guys speak off??

 

+1 there it is

 

I also have this problem, my cats are almost 12 years old and shot. The problem is the driver side cat is an odd shape(its the dual cat setup) and the only thing I can find is the expensive direct fit magnaflow cat. The passenger side cat is an easy replacement with about any OBD2 high flow cat.

 

I just looked up those thunderbolt cats, whats the deal with a metal vs. a ceramic brick, less prone to failure or something? I like how the metallic one is 11" I might be able to fit them in my setup.

 

gut away, the rear O2 sensors have nothing to do with how rich you run, it will smell like its running really rich because the cats will no longer burn off the unburnt fuel from the exhaust (the point of a cat) but it will run exactly the same if not a little be better due to the exhaust being less restricted. the front O2s are what adjust A/F ratio and theyre before the cats. this is also why you can just unplug the rear O2s and the car will still run fine. it will set of a CEL if you dont have the O2s tuned out though

 

Also, if you don't want to spend the money on a tune you can buy some rear O2 sims for like fifty bucks, put em in and it will not throw a CEL

Gutting cats won't make it run like ****. It'll run better, be louder and more raspy generally.

 

This is not true in the least. Gutting the cats will have NO negative effect on performance. Your exhaust will have less restriction.

I took a 2 foot screwdriver, a 3 lb sledge and destroyed the inside of my converter, started up the car sans cat-back and blew it all out years ago.

Rear O2's only verify that the CAT is doing it's job. You can tune out the CEL but it won't affect performance negatively.

 

Hes right, take my word for it too, a tune to get rid of the rear O2's will be wayyyyy cheaper than the cats themselves.