whats the negative effect on the rotary engine when you cut out the catalytic converters.
I noticed the first two "cats", I think, have pipes running back to the engine.
Some one told me, if you cut the "cats" out, you just plug the hole where the "return" pipe went back to the engine.

Help, help, as I think my "cats" are plugged and dont want to ruin the motor.

Also some one told me if you do not have enough back pressure, the tips of the rotors might get cut off.

Thankssss

 

Well, first whoever told you the tips of the rotors might get cut off probably has no clue how rotaries work. Rotaries LOVE free flowing exhaust systems. It will give more power at the higher rpm range.

Give a little more background, what engine and what year are you running etc.

There is no return pipe to the engine that I've seen on my 85 12a. There's a small attachment for emissions that can easily be plugged without issues when you remove the rats nest.

There are others that know alot more details than I do, I'm still new at this point to the rotary.

 

Welcome to the forum and the Darkside. You should state which model engine you have in your 84. If you have the 13B with fuel injection, the auxiliary ports are controled by one of the return pipes off of the main cat. If you have the 12A carbed version, it makes no difference.

Please don't believe everything you may have heard about rotarys, especially from piston people. There are way too many myths and misinformation floating around. While it's true that piston engines need some back pressure, rotarys don't and lack of it certainly will not harm the apex seals or thier corner pieces.

If you do have the 13B engine and remove the main cat, there is a simple mod to keep the aux ports working.

The 1st perfomance mod for a rotary is to free up the exhaust. This means replacing the 2 precats with a set of headers and removing the main cat. If your's are plugging, you can replace, gut or remove them entirely.

In my sig line is a link to the online FSMs, other manuals and books. Download what you need and have fun reading.

 

thanks, its a 84 12 a.
as far as i can remember when i lookede at the cats the first one and the second one had a pipe, maybe it was small, but it was running back to the engine.
there's not very much pressure coming out of the muffler, so i figure the ratys nests are plugged

 

The rats nest is just the mass of vacuum tubes on the drivers side of the engine for emissions. It can be removed, there's a link in the 1st gen faq to instructions for that.

On another note, if that was clogged up, I believe there's a pretty good chance you wouldn't be running at all.

You should have decent flow coming out of the exhaust from the stock muffler, so if you're not getting alot, it's either broken or plugged, and you'd know pretty quickly if it was broken.

 

sorry, when you mentioned rats nest I thought you were referring to catalytic converter.
no, the vcuum stuff etc. is fine, I think the catalytic converters are plugged, so guess just cut them out, eh

 

Well, there are a few routes you can go each with it's own options

New, high flow cat - better high rpm power, slightly louder than stock
replacement pipe - bolt in or custom build, definately louder than stock, I believe gives the best flow
presilencer - keeps exhaust volume down, good flow, increase high rpm power.

Definately do some reading on the subject before jumping in.

*edit*

Please feel free to correct me if I'm wrong on any point, I'd rather have right info than think I'm right.

 

Simplest, and cheapest option, is a replacement pipe for all 3 cats. Increase is sound will be small as long as the oem ehaust manifold is retained. The pipe going to the cat on your 12A is fresh air coming from the air pump. Once the cats are gone, that can be removed too, along with the egr and acv. Block off plates will be needed for the egr and the pipe that went to the cat.

 

I've got a stock cat with very little miles on it if anyone needs one. I had to replace it to meet emissions a while ago and then moved to where there are no laws for it, so I got the RB system.

 

thanks trochoid, i'll do that

 

Dony worry about the EGR valve,only the 1980 CA versions had them.
The 84-85 12A cars did have two metal air injection lines running to the exhaust system.One large pipe to the main cat,and a small pipe to the precats.Both can be removed and blocked off at the intake manifold when deleting the catylists and the air control valve(the box on the side of the intake manifold)
Mazdatrix and others sell the block off plates.....
http://www.mazdatrix.com/e7.htm

Also,if you are going to run a performance or new cat(or any cat for that matter)....then its absolutely imperative that the air injection system and rats nest not be disturbed or removed.The cats rely on the oxygen provided by the smgo pump,in order to reduce emissions and not overheat/clog.Its kinda an "All or Nothing" deal when messing with rotary smog gear.