this past weekend i finally got my 79 to crank up. once it did the shop quickly filled with smoke. the exhaust on the car is horrible, next weekend im goin to take it all off. i was wondering if somebody could explain the rotary engine exhaust system to me. it seems complicated. like what is the box between the engine and exhaust piping? any info on it is welcome. also, are there any performace exhaust systems? if so, what do yall recommend? (sidenote: i like to be noisy going down the road)


eagle

 

You're going to get the same response about the performance exhaust systems:

RACING BEAT -- www.racingbeat.com

 

You got that right. Racing Beat fits and sounds good.

 

That box between the engine and the exhaust piping is called a thermal reactor. It's basically a catalytic converter on the exhaust headers. Rotaries are not the only cars fitted with thermal reactors, but I couldn't tell you what other cars were. A rotary exhaust is pretty much like any other exhaust except it has twice as many converters and the piping has to be much thicker in order to be able to withstand the higher heat a rotary engine puts out.
If you like being loud, the racing beat exhaust might not be what your looking for (although its an awesome exhaust). It's pretty quiet. I think a good combination for an exhaust is performance headers, 2 pipes in 2 pipes out highflow muffler (magnaflow or any other free flowing muffler), and a turbo muffler at the end. It's a tad louder than racing beat's and sounds awesome.

 

I think the best system would be a Racing beat header and streetport center section into a collector and a straight through muffler.

 

Yeah.. and if you like to sound loud (which I don't), then you could do racingbeat Street Port header to Street Port centre section to some kinda fartpipe. That would be loud as hell.

The box right on the side of the engine is the "thermal reactor" on 79s. then you probably have two or three catalytic converters. All of these are necessary if you ever hope to pass emissions test. That or you could put a high-flow cat in to replace the three that are there, but it'll wear out more quickly than it would on a piston-powered car due to the extreme exhaust heat, so you should only use it for the emissions tests then remove it.

Jon

 

No catalytic converters on a 79. Catalytic converters replaced thermal reacters in 81. The heat exhanger located after the thermal reacter is commonly mistaken as a catalytic converter though.

 

Late 70's BMW's had thermal reactors. Lots of problems related to them as well.

 

thank you for all the help. sounds like yall like racing beat the best. and about emissions... i live in the country and dont care about emissions (i have a straight piped cummins). so do i have to have that thermal reactor? also, what is the little thin pipe that runs right along side the big pipe?

 

Pull off the thermal reactor and put on a racing beat header. There are lots of ways you can go with the exhaust after that but the RB header is just a great piece. You will get rid of that smaller pipe when you ditch the stock exhaust.

By the way, the thermal reactor is a bitch to get off. The upper left nut is nearly impossible, it took me about 2 or more hours with several different methods to finally get lucky and loosen it. Save yourself some time and drain the coolant and pull off the intake manifold, then you have free access to that PITA nut.

Marques

 

aight so i should just get rid of the thermal reactor and put a header on it? the header just bolts right on to the block where the TR was right?

 

that's right. just take off the TR, then bolt on the header. you will be pleased with a header. it is great. where do you live in georgia? i love living in the country. their aren't any laws about what you do to your car!

 

yeah living in the country's great. i live in a little town called bonaire, its just south of macon.