cheap toy racer exhaust
 

I recently bought my first RX7 (250$ 84 12A 5sp) Started it for the first time in 5+ years. After sitting in the lovely WA weather outside on a chicken farm. Lets just say, the body has seen better days and the rats have made a nice home in the interior. So i figure I'll try turning it into a cheap toy racer (rallyx & autox).

Only problem is the exhaust is toast. Witch means i wont be passing any tech inspection.

I've read a lot of threads about exhaust, but they all seem to be the same. Racing beats exhaust, witch is not cheap. Id like as cheap as possible. All it needs to do is pass tech, noise level rules and not make my ears bleed.

I don't need to worry about emissions laws. So i don't need a cat(?).

I was thinking of just doing a cherry bomb ol' skool to some cheap ebay muffler, then running the tip out the side before the rear tire.

would this be ok, Or would i find myself screwed come tech inspection?

Hello there,

I am in Seattle and as far as I know there shouldn't be a tech inspection unless it was a branded title? or previous ins damage?
I am not trying to sound ignorant or anything but is there something that would bring up a needed inspection?
I know of a couple of folks if you needed work done I would have to check with them but they do amazing work :)
PM me if you need any help
thanks much,

~Tim

PS. If it is D.C please ignore this reply lol

Dont cheap out on the exhaust. Rotary exhaust temps are very hot and will fry glass packs and cheap mufflers quickly.

There is no tech inspection as far as I know, here in WA. Unless you meant Western Australia, and from what I've read on forums, there will be.

Hmm, you said lovely WA weather. You must be talking about Washington State and speaking ironically because it always rains here. If so, you should be ok without a tech inspection.

Maybe try asking this in the region specific sections. Look for the NW section. Good luck!

Oh and do lots of searches for rotary exhaust ideas. They need thickwall .120" or 11 gauge mild steel tube or possibly 14 guage SS tube or shedule 40 pipe. And the mufflers have to be like super tough. Also look into long primary because it's the only exhaust worth custom building if you're going through the trouble. Otherwise look into buying a full exhaust from Racing Beat. No other places sell 1st gen RX-7 exhaust systems whole anymore as far as I know. Maybe score a used mindrtrain or a new but crappy pacesetter.

i put a cherry bomb on mine, and it lasted 2 laps, and now its literally melting off of the car....

if you want to street the car, with headers, the old school method was to get 2 racing beat presilencers, and two of some kind of turbo muffler.

the rotary has no exhaust valve, and a really good flowing port, so the pressure waves are much stronger, and the engine will disassemble mufflers that would live behind a v8

wow thanks for all the reply's first off, But i feel like a jackass for not saying what my intentions are for the car. The car will only be used for Rallyx & Autox. So I dont need to worry about it being street legal. What i meant was pass SCCA tech inspection. The car is past saving (Wa State weather). I figure this is the best way for it to live out the remainder of it's life. Putting a shit eating grin on my face:egrin: .

The car wont be running for long periods of time. Just the time to pull up, wait for my turn to do my lap, Run my lap then park until my next lap. I guess i might drive it up and down the street to work out any problems or whatever, But that's it.

The cherry bomb i am looking at is louvered not packed like the others. So i don't see why it shouldn't work?
http://www.summitracing.com/parts/imm-87885cb/overview/

As for the muffler i figured I need a turbo muffler of so kind. I'll find something cheap that doesn't look like it will fall to pieces and use it.

That thing will melt.

Try the dynomax "Bullet" mufflers. They are still fiberglass packed, but its "Ceramic Fiberglass" and it actually holds up pretty well at the end of the exhaust system.

Ive got a $40 thrush universal type muffler from advance auto parts on the end of my 12a, and it's been more than fine for quite a while now. My son drove it every day for a year, and well, it has an easier life now that it's mine, but still....

See thats more my speed. I'm not ready to dump $1000 into a exhaust system. Since the 12A has 160k+ miles on it. Its never been rebuilt, So I'm not sure how long its going to last. Last think i want to do is drop a grand on exhaust. Then have the engine goes tits up.


Whst Do you have in front of the thrush? or is it just the muffler?

Mine had one of those for 3 weeks before it was burned out, but ok.

It was also loud as hell with it, and restrictive.

Is there any setup i can do for around $200. I'll be welding and installing it myself. So i don't need t factor that into it and im just going to exit the tip before the rear tire

This car will be driven less than 500 miles a year. It wont be tabbed or insured. This will purely be a AutoX and RallyX car. I just need it to pass SCCA RallyX & AutoX course noise restrictions.

Mine is stock exhaust, the thrush on the ass end because the stock muffler fell off. SOrry, wasnt gonna go the $300 for the new one. Probably got 12,000 miles on it, no, its not burnt out, no its not loud, no it didnt melt or anything, I swear. But then I don't beat it to death either.
Shit, my whole RX cost $500.....Im not gonna spend a grand on pipes either.

another thing to think of is exiting that exhaust before the right rear tire, SCCA people have noted in the past that due to the extreme heat of a rotary you could over heat that tire during the course of a session, people either point the exit at the ground or exit behind the bumper.

You can pick up dynomax "Bullet" mufflers for less than $40 bucks. This would probably be your best option.

Obviously you are not wanting to spend what the car costs on just the exhaust but keep in mind one of the largest performance factors on rotary's is the Exhaust.

and @Georgethefierce is also correct about where you are thinking about dumping, I have seen melted tires more than once because of that, look for dumping right after the wheel or out the back.

Bonez makes a track pipe setup under $200. may be available elsewhere also RX7.COM | 1979-1985 Rx7 Exhaust (330)7-ROTARY
I had their street setup and liked it, though it was pretty loud.

double post

If I was you Id just rig up a clamped straight pipe exhaust off of a RB or Pacesetter header then clamp it to the stock over the axle pipe. Cutting the flanges off the header and over the axle pipes. Then get a cheap RB universal muffler for the tail end. It will be loud, but its a track car. Plus it will be reliable and not melt.