Is there any draw back to cutting of your cats? Will it affect how the computer gives teh car the proper A/F ratio? Or anyother complications?

 

I don't think you will get much out of doing it if they are in good shape, other than noise if you have a dual cat setup. My experience has been that you don't see any gain from this mod unless the cats are plugged up, if it is done on a stock motor.
JMO

 

with my car I just got a high flow cat from MAC. It is nice light weight and very free flowing. Infact it flows so well it is like having a 3 inch piece of pipe in place of the cat. Oh wait that is what it is. The reason alot of people don't see gains from gutting the cat is they have flowmaster exhaust. the flowmaster mufler is like sticking a cork up the motor's but.

 

Whatever,

I have CATS and ran a 13.58 UNCORRECTED ET in 90% humidity. I have done it twice and have seen absolutely no gains. I don't have a Flowmaster either.

 

I have a particularly strange problem with my Z. Reubilt engine, AFR heads, ZZ3 cam, ported intake, 24lb injectors, crane ingintion, ect.... THE car has about the same power as the stock engine! After 1month of the life of the engine, it "opend up" and had tons of power! Well, then I put my supercharger back on 5mo. later. I blew a head gasket. Tore it down, and after the rebuild, the car has no power again?? I runs fine, just no power and gets hot in stop and go traffic. The car starts overheating in 80deg. weather in stop and go traffic. The only thing I have not done is cut the cats. And when the cats' get hot, I'm sure they expand and cause even more of a restriction, thus, MAYBE my overheating in hot traffic and lack of power is the result of restrictive cats? I was told that they were "high flow cats" from the muffler shop due to the 3in diameter. But then, 3 in diameter may not have "high flow Interals"!

I have tried everything
Wide band showed OK 12.8/1,
Checked cam timming, OK
Valve lash, OK
New ECM, OK
NO results, checked the cat, ONE OF THE TWO, looked oK. The shop said " no need to look at the other since it's not gettin "Hot or sounds like it's broke"
I got to thinking, maybe it's too much of a restriction? So I"m going to cut the cat's to see if that is the problem.

 

I totaly disagree with the statement that gutting has no benifit. I put a Flowmaster on mine and didnt see their estimated HP they predicted. Until I gutted my cats (2). It was two diff. cars. If emission testing isnt regulated like here in Oregon, It should be your first mod to the car.

 

I didn't believe it either. I did it and it didn't help on 2 cars. It will help on a car that has plugged cats, I have had that happen too, but if they aren't it won't do sh@#. I just know that my 2 cars that have had this done to them didn't pick up jack sh@# for power and it is a lot of work. Go ahead do it, I did, and when it doesn't do anything, remember this thread. I think the dual cat setup outflows the crappy intake, heads, and manifolds that are on these cars, so it is not the restriction.