i recently bought a 86 rx-7 na. I put a new front and rear caytalic on and they get so hot they glow a orangish red, they are the correct parts and the exguast overheat light doesn't come on becouse of this. I was wondering if their is anyway that they could run cooler, or if this is normal. Usually only happens on stop and go driving.

 

no one knows cause we all took it off....

 

It's a rotary thing. Don't worry about it...and don't park over dry brush...

 

Yeah, they put all those heat shields around the exhaust for a reason.

 

do you notice any loss of power?
where did you buy the cats at?

 

Is everything else hooked up correctly? Like the air pump and the fresh air supply to the cat. If not you will soon be replacing the cats.

 

no loss of power, i was just concernd. never owned a rotary before.. will it hurt my car to straight pipe it to the mufflers

 

I just gutted my cats on friday (meeeeeeeeeeeow). Everything runs fine... loud (not too bad), stinky (smells like im running a little rich), and fast (it was slow as hell with plugged cats). If you do not have emissions testing where you live empty those suckers out.

 

Yeah..where did you get the cats from? Were they new or used? Did you connect the fresh air pipe?

Yes, rotary exhaust is hotter than normal cars, but they should not glow red. I'd say either the cat isn't designed for a rotary, or maybe the cat is clogged.

 

I've seen OEM ones glowing. My friend had a beater FC to tear up. Actually, the whole thing was glowing all the way to the Y pipe. I guess thats what running at redline for a few minutes does. BTW We hit up a parking lot and did a bunch of donuts. Now I have that motor in my car.

 

well they're brand new, i bought them from e-caytalic.com. it says they were the right one's for my model and year. So how exzactly do you empty the cats out? or if it comes to that should i just straight pipe it?

 

if it glows orange, your cats gone... burned the ceramics inside.

You need a high flo cat

 

glowing new cats definitly sounds bad if money is no big worry just replace your exhaust you get more gains in hp while your at it if your straped for cash then get a high flo cat

 

If you bought 3rd-party cats, they're probably not designed for the terrifyingly high exhaust temps that rotaries generate. Chances are they're melting down inside. Pull them and check. If they are melting down, get a Bonez high-flow or a straight pipe. You can just gut the cats, but that leaves a fair bit of turbulence in the exhaust stream and turbulence hurts power.

 

Hey you guys talk about not hooking up the tube that goes from the cat to the ait pump.... What does this do? and what happends if you dont hook it up?
always wondered what that was for.
thanks!

 

if you don't hook it up it up to the air pump it will kill your cats.

 

It's called a Split Air Pipe. It feeds an anemic amount of air to the catalytic converter during most driving conditions. A bit more air is sent thru this pipe when you engage fifth gear. Go to fifth gear and the Split Air solenoid opens and gives the cat that bit more air.

Back to basics.........MOST ALL the air that the airpump delivers to the air control valve goes to the exaust ports. It passes thru the acv....goes thru passages internal to the *irons and rotor housings* and exits at the exaust ports. In other words at the point the exaust manifold meets the rotor housings. There is where the airpump air is mixed with the exaust gasses from the engine.

It sounds to me like your timing is off pretty far or your dumping a lot of fuel into the exaust for some unknown reason. Check the timing iwth a timing light. Then make sure your engine has the stock fuel injectors. They should be low resistance injectors of appros 2.2 ohms. The part number of the injectors is embossed on the fuel injectors near the electrical clip. Compare that number with the injector part numbers for your year/type engine. Do a SEARCH on this forum.

 

Thank you HAILERS! that helps alot.
so then is would be fair to say that considering the split air tube does nothing unless in fifth gear, that is does not harm your cat to not have it hooked up?... corect?

the reason i ask is because i just installed a new Bonez free flow cat in my turbo, but i have not hooked up the smog pump/split air tube yet. (plans of doing this in the next week or so... need to pass emitions here in california)

thanks again for everyones help.

oh yeah, does anyone know why air in injected into the cats in fifth gear?