crankit

The air supply hose that goes to the catalitic converter has a check valve in it. Can you by pass the check valve and will it do any harm? Mine has been disconnected for a few years and I think I might of fried my converter starting to come apart inside. Also the port air switching valve has a hose coming off it where does it go to?

eddierotary

iTrader: (7)

depend what engine you have

crankit

This is for an 84 12a engine 5sp

jbontke

A catalitic convertor has to have a source of fresh air to work porperly. If it runs with out fresh air it will become clogged and be ruined. Random Tech makes cats that don't require fresh air, I believe they call these cats 2-way and when it has to have an air pump they are 3-way cats. The check valve keeps exhaust gas from traveling back up the pipe.

crankit

got my answer thanks

85RX7GS

iTrader: (1)

Just leave it how it is. That's the way it's designed to work.

peejay

All RX-7s require an air pump with the converter... as outlined in a previous post, multi-stage create the oxygen needed by breaking down NOx, which is naturally very low in rotaries. The converter(s) need to be supplied additional air for the chemical reaction to take place.

The check valve is necessary because the air pump doesn't pump air to the converter 100% of the time. Without the check valve, exhaust gases will backflow up to the ACV and potentially melt the hoses, etc.

riffraff

what if you are running the setup only for emissions.. then can you hook the airpump up directly to the cats, for oh say a few hours, and then swap back in your more perminate exahust (disableing the airpump), and actually have the cat work well enough to pass?????

rxtasy

good question...although i think it's too late for my cat, would havebeen good to know. checkout my emission dilema

https://www.rx7club.com/forum/showth...threadid=60549

peejay

you could try it... i'm going to HAVE to try it next year... I've heard of people doing it with success, but I wouldnt have it on any longer than it takes to get the emissions test.

riffraff

i was planning on running my presilencers for the most part.. just throwing in a couple cats for emissions.. that way there is not much of a worry about burning them out. the biggest question, though, would be will it work

i really donot want to have to put everything back to stock

OtakuRX

iTrader: (1)

How much of a boost do you get when you remove the cats and air recycler system, other then the obvious money saved from not needing to service the system anymore. Also how many states test cars over 19yrs old for emissions? Because I am thinking of moving to FL after I finish college and I want to remove emissions and I don't want to have to worry about emissions.

SilverRocket

Well, the cats are a major flow restriction in the system, so removing them should net a nice boost. I'd suspect something in the neighborhood of 5-10 hp. For the full effect, however, a header to replace the stock manifold is the real deal. Full exhaust on an FB is an awesome bang-for-the-buck mod, and is really the first mod you should do. The full Racing Beat exhaust is good for about 20 horsepower over stock (very noticeable).

OtakuRX

iTrader: (1)

cool, ya I was asking cuz I have a header, but wasn't sure about replacing rest.

SilverRocket

You mean you have a header that fits with the stock cats, or you have an aftermarket cat too?

If you have a hi-flo aftermarket cat, if might not make too much difference to lose it.

crankit

Lucky me my state does not do emissions tests yet on older vehicles. BUT when I got my car it didn't have the hose hooked to the cat, no joke, so anyway now it rattling inside the cat. Probably fryed it.So whats my next concern ? will it plug up or just not pass emissions test?

TheAMAZINGNorad

Im undergoing a similar delima. My cat is going, and i dont want to put another one on there. IS there way to somehow take the Racing Beat full exaust BUT put a high flow cat on instead of the pre silencers? That would be alot better than stock right? Ive got to pass durn emissions, so i cant ditch the cat. What do you all think?

mar3

iTrader: (8)

Did you ditch your air pump? If you didn't, there's hope...call the guys at Rotary Performance in Garland, TX on how it's done with the stock diverters and solenoids...

riffraff

theamazingnorad: i have a full racing beat exhaust and am planing on getting a custom cat pipe made to fit in place of the presilencers for emissions purposes. just get the necessary flanges and do the same. that way you can run with the presilencers normally and just through on the cats and airpump for smog