RX7 issues man! Overheated exhaust
 

I am recently the proud owner of an 88 rx7 NA

I bought the car for $500 and This is my 3rd 2nd gen.

Ive been scrounging for parts and putting things together one bit at a time.
The previous owner stripped the poor thing, and its interior is bear nothingness.

Im having issues currently.

It came without an exhaust.

So I went to the muffler shop today and put on a new 2.25'' piping from the stock header, into a brand new cat, and then small muffler that I placed in the location just before the factory Y.

Problem.

I started my trip home and I started to feel hot... very hot.

I look down and through the shifter boot I can see a red hot cat and the piping following it. S***!

I drive back and the guy checks it out.

AFTER the new cat, everything is black and charbroiled.

they cut the pipe and looked inside the exit end of the cat and flames must have been eating at it. But not all the way through.

It seems like the new muffler was ''clogged'' or something...

Hes going to try a different muffler again on sat.
But im worried that the car caused this problem somehow?
Is there any way the car wasn't right? I didn't hear any back firing, but the car would NOT pick up speed.

The entry side pipe of the cat was fine, (looked new) and most of the honeycomb was fine and intact on the entry end.

Please help. Ive never had this happen to me with a new muffler...

What kind of muffler is it? Rotaries have been known to melt glass-pack mufflers due to higher EGTs than a piston engine.

You should also replace the shifter boot if yours is damaged/missing. Exhaust inside the car is not a good thing.

Consider looking at the operating temperatures of the cat, as well. As was mentioned above, EGTs are notoriously high for rotary engines. If you have the ability to check your A/F mix, I also recommend doing that.

yeah sounds like you probably melted a shitty quality cat or muffler which clogged. it not abnormal to be glowing red hot a little right after that cat since the honey combs inside glow red hot to do their job -- burn unburnt fuel :) so dont worry too much about that.

Ive tried two different cats, the first one cooked through.

The second one i tried was slightly different, but i didn't use a muffler this time. The cat STILL got red! That and performance was crappy.

I found my o2 was not connected, but even though I connected it, it still got hot.

I need to know what would cause this.

Compression test the engine.
There may be a chance that the cat is getting unburnt fuel due to low compression in a housing.
Try that first.

Before putting the new exhaust on it, did you run the engine at all? You may just be looking at an improperly stabbed CAS. If the timing gets retarded enough, you'll end up burning fuel in the exhaust system. That's a surefire way to make it start to glow.

Holy crap man be careful with that. It would be such a shame to burn down such a beautiful car.

YES! YES YES YES YES YES!!! ook. its not the compression...

but yes its still a problem.. ill check the timing later.

Can somone tell me how to check the timing?

You check timing with a timing light. If the engine is idling below 1000 RPM, ignition timing will be -5* / -20*. There are 2 marks on the main pulley that you should see line up with the pin on the front cover depending on which plug wire you've clipped onto.

To align the CAS properly, the FSM and these threads will help:
https://www.rx7club.com/showthread.p...ghlight=timing
https://www.rx7club.com/showthread.p...ghlight=timing