I recently bought a 87 rx7 and accidently cracked the exhuast between the 2nd cat and main cat while towing it home. My question is....will it damage the engine if i get rid of the 1st and 2nd precat's and replace the main with a high flow cat? I'm on a low budget so i'm trying to keep it cheap with the most gains.

 

It will help it..."the better the flow, the more the go!"
I'd say get straight exaust but I don't know if you could pass emissions like that. If you don't have emission laws get rid of all of them!!!

 

I agree with Nashman69g 100%.

 

hey yagotrice i did exactly what you wanna do, to my 88 gxl. wow, did it wake up my car. i havent done much to my car, but this really did make a difference. it did make the exhaust a few notches louder, but damn it sounds great. go for it yagotrice.

 

Quite the contrare. You'll benifit tremendously by removing your Pre-cats. Our engines need to expel all the hot gases as fast as possible. Infact, the Pre-cats are probably original. You owe It to yourself to remove those clooged clutters anyway.

 

Pre cats really are only used during warm up and minor minor helping of the main cat when heated.

 

I plan on pulling all the cats on my 88 non turbo gxl. is there a backpressure line , on the exaust , that i need to plug or remove ?? anyone?

 

hey yagot, where in Michigan are you from?

 

Screw the cats and just get a resonator if you're worried about noise level. Unless you have emissions... But if not, the resonator will be straight free flowing, and kills the big noise factor. If noise isn't a problem, then just get some straight pipe. Any muffler shop should be able to make one for ya. My father has a resonator on his gsl-se and it's great. Cheap too! Most of all though, dump the stock cats. They're really restrictive.

-Kanaida

 

Where can you get a resonator and what exactly does it consist of? Is it just some real thick piping or what? Thanks.

 

if ya take it all out youll be a ricer cause youll have a loud exhaust! and mods! even worse than a power gain!

 

from my understanding, its shaped like a muffler, without all the piping inside....

 

its basically a straight-pipe with some "wings" in it to deaden the noise a little...

 

It's sweet, you'll actually be able to hear the engine! Just get a high flow if you need to pass emissions, and a pipe/silencer if not.

 

hey 6port,
i live in northville...

 

"Cats? We don't need no stinkin cats!!!" lol
Click Here

 

a resonator is like a muffler, yes, but not nearly as wide. if you have for instance, 2 in pipe, and you want a 2 inch flowing resonator, it'll only be as as thick as say, 3" piping. The inside is a straight flow with no restrictions, but if you look in it, you see almost like a mesh metal sheet that forms a tube, and it's weird. Almost like a filter of some sort. Hard to explain, but very functional!

-Kanaida

 

can you just remove the cats or is fuel management a necessary thing to upgrade when you do it ....cause without backpressure then it would up the boost creating boost creep . and run lean

am i correct here

 

Yes, for a turbo. Either way you will experience the "rotary smell" with no cats. I don't like it but most don't seem to give a ****.

 

If your car's an n/a, think about Bonez race pipe.

 

I agree, remove them. Except in my case when i did this the car smelled BETTER! It used to stink with cats and now no smell at all....Weird

 

Alright, I went out to the garage and took pics of a resonator I had laying around, hope this helps you see what it is...

 

^

 

ok i removed the cats but what do i do to the tube that went into the main cat....do i just plug it up????????is there anything else i should do??????

 

depends what you're replacing it with. That's your actuator for your 5th & 6th ports. If you go the route of Cat Replacement Pipe that Racing Beat sells, it bolts right up to your exhaust, and also to the actuator pipe too. If you go to a exhaust shop, and have them slide a piece in there, then I don't know. I never did replace the cats on my n/a when I had it back 2 years ago... One of these other guys should be able to lend an answer to that one. What DOES he do with that pipe? Obviously he should wire open the ports... Get some Pine Apple sleeves for better flow and what not. Does the pipe remain?

Nice Resonator Rxmfn7! Perfect timing. Thank you.

-Kanaida