Hey all, I'm driving an 88 GXL N/A with no mods and I'm looking into doing the exhaust. Now I'm pretty much an idiot when it comes to a lot of car stuff so I've been trying to do a lot of research when it comes to doing this. I'll more than likely have a muffler shop do the work but I want to know exactly what I should be looking for. What I've found so far is that if I replace both the cat and the catback systems with high flow systems that I'll get a horsepower boost but when I looked at the schematics I found that there are two pre-converters before the actual converter. If I replaced the cat with a larger size inlet and outlet what happens to these preconverters, do I just have them tossed or do I have to replace them with something similar? Also if there is another thread out there that explain this please link it I couldn't find anything by searching that answered this

 

Just depends, Do you have to get smog tested in your area? Here in OK we don't have any testing so I remove the cat and two precats on my fc's before. If I was considering just going to a high flo cat I would probably have the pre cats removed also and just use only the high flow cat.

 

I live in Arizona so I still have to go through emissions and that kind of stuff so I do need a cat I just wasn't sure if the pre cats were still important. If not I'll just have them tossed.

 

i would just buy a catback exhaust, not hard to pull it off and put a new exhaust, on my turbo ii i have a 3in downpipe, racing beat highflow cat, and its just open pipe all the way to the back until it hits the exhaust tips

 

I guess that leads to another question I have. If I just get the cat back do I need to get it in a size that matches the original or can I get a larger piping size?

 

How does that make for the exhaust sound? I've been looking at down pipes for my turbo since it leaks but I can't really make a decision,I'm trying to keep a clean sound I'm one who honestly isn't a huge fan of the extremely loud brap, but hope to still improve the exhaust flow for some hp,I was thinking the best option would be like what you did,a name brand dp,then I could go to my local exhaust place and have a Midpipe,or possible raving beats pre silencer. it already has decent y pipes installed so i planned on keeping those.

 

The catback system will probably be a larger internal diameter pipe than stock, but should bolt up to the stock catalytic converter. So you'll get a small gain in horsepower and it'll sound much better than what was in there.

 

For a high flow replacement, I'd recommend either the Bonez Superflo:

RX7.COM | 1986-1991 Rx7 Exhaust (330)7-ROTARY

Or the Racing Beat Header with the Superflo cat (another they offer).

For a catback I highly recommend Racing Beat.

Power Pulse RX-7 Exhaust System for 86-92 RX-7 - Racing Beat

 

Y, you can remove the precat and it will still pass emissions.

Racing Beat is pricey, but I puruchased and installed a few months ago and the exhaust has a great sound.

 

jesus **** I need to just do a ride along video of my setup. Cheap, plenty of flow for a DD, and enough for a track day on a stock ECU.

RB Collected Header to Modified Cat to retain 5/6th ports NA, back to a OE NA y-pipe, to Bosal OE replacement Mufflers. Cheap as ****, sounds great, and it sure as hell picks up better then stock ever did.

All into this for under $300 new parts. I paid $150 used

 

Awesome yeah this is what I was wondering about. I have some ideas about what parts I already want but this makes the decision much easier. I just wanted to make sure the pre converters needed to stay or go. Thanks for the help everyone.

 

i think it sounds great, it is fairly quiet unless i get on the gas and then it gets noisy, i have to work at 4 am and i let my rx7 warm up for 5 minutes and i have never had a complaint from the neighbors about my cars noise in the morning

like i said its pretty loud when i get on it and quiet when i am just cruising along

 

That sounds perfect! Still have the air pump?

 

Yes sir I do. 5/6th still work very nice. high five!

 

If you want it to be obnoxiously loud, spit fire and give a decent HP gain you could cut out all the junk from the exhaust manifold back and have Jim Bob weld on a 2.5" straight through pipe to a Cherry Bomb sticking out the back. Won't pass emissions but it sounds great and who doesn't love a flame spitting rotary?

 

For about a week until the EGT's burn out all the fibreglass packing in those shitty mufflers.

And no, it won't sound great, even before the packing burns out.

 

And people ask why these cars get so cheap so fast.

 

and the clean ones I buy in a heart beat.

Seriously. Read my post and sit back and think about it. Cheap functional exhaust. Not sounding like ****, actually performs, and does not cost an arm and leg.

 

just buy a racing beat cat back and call it a day. the new sound will at least make you feel better.

retaining the cats is the largest hinderance to power, so no matter how much time you put into tuning the exhaust or how much you put into it the gains will be almost nonexistent. but if you have to pass emissions that's where you are.

 

Exactly. While they are a bit pricey new, they can be found in the classifieds at a reasonable rate. I live in a state where its emissions free. We have an abundance of trees. Or, at least that is what I tell myself why we do not have them.

 

I've had mine setup like that for years now and not had a problem, it did burn out the cherry bomb right away but I knew that was gonna happen before I put it on, $80 man. Get compliments on the sound too, granted they also say it's ear splittingly loud, but never had anybody say it sounds bad; I don't get why everyone on here says that.

I plan to put a better one on eventually but I just enjoy driving it the way it is and the raw sound it puts out now. I'm the second owner, my car used to be a garage queen, now she's just haggard. Hahaha!

If you wanna get a legit setup though go with Racing Beat, they've been tuning these engines for decades now and obviously know what they're doing. From what I understand (And correct me if I'm wrong here folks.) rotary engines don't need the same back-pressure from the exhaust as traditional engines do so the quicker you can get it out the better. The only way you're going to see and feel any real improvement though is if you get a header back system with a high-flo cat, a cat back will give marginal gains but just like the other guys said the more flow, the more you'll go.

 

That's because the people that hate it either don't talk to you or lie to you. The IRL automotive world still mostly works on the principle of, "If you don't have something nice to say, don't say it at all." Hence why they fudge it and say its too loud in a jovial way. It's not a compliment.

 

i give enough hate on the forum, i don't need to be a dick in RL too. quite the opposite usually.

but unless it emits the sound of a turbo 3 rotor or a 4 rotor and it is as loud as you say, it already doesn't sound good to me even without hearing it.

 

still saying go with something like mine. If I can find someone to hold a camera I may take video.

 

I have a mostly stock S5 n/a with a CorkSport header and a Catco replacement main cat in the stock location. I have tried two difference cat backs and kept the Borla setup on the car.

Replacement type cat back exhaust;

Borla cat back exhaust;

What I have learned from all this is that once you put a header of any type on a n/a rotary it will never be "quite" again.