livewakesnow

so i was wondering if taking the cat out of my exhaust would be bad for the car, i know it would be bad for the air, but i dont ahve to emissions done on it. it would also give my car a couple horses. could i do this job by myself? how will it sound?

tickwon

I notice a difference without it. I will sound louder. If it frees up any horse power it's very small. Think of it this way...less restriction and more flow. Or if you want to spend the money get a high flow CAT, that's always a good option too. I wouldn't take this to a muffer shop and say can I have the CAT taken out...they might have a monkey.

Chris

DynamicJ

dude, take it to a muffler shop, and tell them you just want a straight pipe ran all the way back! AWESOME sound..

jfairladyz

Most muffler shops that are **** about that kinda thing will make you a straight pipe, and just not instal it. I've done this on a couple cars, they said they couldn't knowingly violate an emissions law like removing the cat from a street vehicle. They said it's a federal violation and their shop could be fined. I would then just instal the pipe for racing, and put the cat back in for street. It only took a few minutes. I had them put flanges on all the pipes to make it easy. Of course being in a non emissions area, you could just leave the cat off. But yeah just ask them to make you a pipe, just don't ask them to install it and they won't make a big deal of it.

Bleach

For you Seattle folk, me and a few friends know of an independant muffler shop that does good work and will do anything on any car. ...as long as you pay in cash.
he'll make you a removable test pipe, straight pipe, whatever. Even on a newer car.

livewakesnow

hmm i live in seattle, you should give me a name

cm3

Anybody know of a site to get a high flow catalytic converter for an 82 n/a ? or does anybody have one to sell?

81 Black L28E

I have my cat removed..I did it not that long ago... It makes a good bit of diff in sound ...I dont think it adds all that much HP but its worth the time.. they make this pipe its called a test pipe it listed for a AE86 TOYOTA CORROLLA ...It fits just right .I got mine for a $20.00 bill from a friend ..I think there listed for $60.00 bill...

cm3

Where would you find this test pipe?

81 Black L28E

My friend says he got that one from a toyota site i cant remeber witch one ..

Z*Tech

The test pipe fits where the Cat normally sets. It is designed to test to see weither the Cat is restricted or not. Sometimes people "forget" to remove it.

Warning is that more and more states are bending over to the Feds and requiring the emissions to be controlled. Don't dsipose of your Cat, you might need it in the future.

lww

Especially if you get a bolt in one or have one made with the proper flanges.

You bolt on your cat for the emissions test and then replace it with the 'test' pipe when you're done. This will also keep the cat from being damaged through 'normal' use.

zracer420

it a track more unwanted atnetion like cop and **** i have it dune and i am consetly get pulld over but there is some hp gains but there is more copers waching then

jfairladyz

On a stock NA though, gutting or removing the cat ain't gonna do much for you. On a turbo car (or modified for performance NA) you'd see more gains as turbo's thrive from a lack of back pressure. Until you're pushing the limits of the stock exhaust, modifying it wont really do much for performance. And remember a full exhaust will only give you a few horsepower on an NA anyways(and thats to the flywheel, by the time it hits the rear wheels, you're not even really gonna notice it except for the sound). And gutting a cat is no fun, I've done it and it's not worth it. Getting a test pipe is alot easier(though more expensive). There are also higher flow cats you can have installed, though most aren't legal in CA. All in all, if you got a turbo Z (or an NA thats got some performance mods) then it would be worth while. Otherwise, spend your time and money else where.

WildmaN

I am planning on cutting out my cat with a reticular saw. Gutting it out, and sticking it back on with clamps. I want the sound more than the HP, it will sound more like the car is supposed to sound. Like a roadster! Oh yeah!

jfairladyz

If you're just going to clamp it back on, you might as well go down to the autoparts store and buy a short peice of exhaust pipe for a few bucks and cut it to size and clamp that on. That will save you alot of time and it's easier plus you'll still have your cat if you ever need it (you never know). Once you start trying to gut the cat, you'll wish you woulda just got the pipe to begin with

WildmaN

Hey all I want to do is have it there, so it looks like it is functional. That is my idea, I don't mind the hard work of gutting it out. Because I am going to leave it on there hollowed out. Because of emissions mainly, and the fact, I wouldn't have to keep switching the things out every 2 years! By the way, what is the best thing to gut out the cat with?

Z*Tech

I have a cat in my 1982 280zx, its original and still passes emissions.

If you are having to change out the cat every two years there is either a problem with the engine, the gas you are purchasing, or your driving habits.

As I have previously stated on this website, I hate the Standard Oil Company. They are not nice people and are largely responsible for the obsurd prices we are charged at the pump. However, the Chevron gasolines are the best for use in the Z's and many other quality vehicles. I have personally observed Z's with over 300K miles that have clean cylinders, valves and injectors. The three common cproperties in these cars where the use of chevron gasolines, Castrol oil products, and great maintainence.

That said, never use any gasoline containing methanol, it's just plain junk, it will mess up your cat and is not compatible with gasoline, go figure.

The Z and ZX series of 280s are now pretty old and driving them hard will cause oil leakage into the cylinders, as the valve guides and piston rings are usually showing signs of wearing and the valve seals are harder than bricks. The 280 engines require a certain amount of back pressure to perform properly, removing it and driving hard will take out the engine sooner.

The ZX was never designed to be driven hard, it was built to be a fairly comfortable sports touring vehicle.

About every six months I drive my ZX for about an hour on the I5 interstate north of Seattle, this heats up the cat sufficently to cause it to act exactly as a self-cleaning oven works. Interstate 10 in the Mesa area would be a nice drive, set the car at 70mph and relax for an hour.

You talked about the sound of your engine, that is controlled more by the muffler than the cat.

As for the original poster with this question, it is not a good idea to remove the cat.
It will cause a feedback to your O2 sensor and cause the ECM to misadjust to air-fuel ratios

WildmaN

Oh no I was saying, I wouldn't have to keep switching from the pipe to the cat, and back again. For emissions purposes. And I know the cats on my Firebird muffled the beefy sound that she had. But I had to put them on, to pass emissions. Frankly my firebird, runs and sounds better without cats. But I have to leave them on there. Maybe a fuel injected car can't run efficiently without cats. I guess that makes sense, but if my cat is bad I am going to gut it out. Because I am not going to spend the money on a new one. By the way my cats are original on both of my ZX's. Also I always use Chevron fuel for my cars. Only the best for them!

Z*Tech

That being the case I would suspect the cats are fine

assimilated420

you talk about back pressure.. only for the NAs.. turbos need as much flow as possible.. if your car is NA and not pushing high numbers... leave the cat..

Z*Tech

the car in question is normally aspirated

WildmaN

Yes my Z is n/a for now.