Cat-back or straight pipe? what's louder? What helps the car last longer? Help? I have a n/a 12a thanks guys.

 

straight pipe would be louder and the exhaust system has nothing to do with the longevity of the engine.

 

Depending on the model year rx7 you may not have a cat but we can't tell.

Anyway, what Michael says, ones just a lot louder than the other.

 

Cool. And its a 79. Thanks guys. What's better for performance?

 

a 79 doesn't have a cat

 

No muffling sounds retarded. You sir, need to research more.

 

We took ours ('82) to a Muffler Man today, some one ditched the cat and put in a glass pak where it used to be, I think the muffler is stock yet. It sounds pretty terrible. Might try a different muffler. Don't really want to go back to a cat just for sound. Shop said $250 to redo it back to OEMish. Would rather throw on a generic $20 muffler. Thing sounds like a snowmobile.

 

Rotaries are pretty picky about mufflers, especially in the cat location. You certainly won't be getting away with a "generic $20 muffler" if you want it to sound reasonable.

 

I'd get an RB Muffler. Well worth the price, and me and many others have them used for a good price. Sounds great with a single header straight back to the muffler, no resonators. The SP exhaust is great as well.

 

My turbo sounds amazing with a 3" straight out to a magnaflow. If it was N/A I'd put a couple straight through mufflers along the way to act as resonators.

 

I just got my exhaust finished earlier today. 3" full exhaust, 2 foot long presilencer, to a 3" universal RB universal muffler. I cant believe how quiet the car is. RB makes great quality mufflers.

 

They do, which is actually why I went with a Magnaflow for my main muffler (with the "medium" RB 3 inch presilencer). I wanted it to make some noise!

NA motors are really loud with 3 inch exhaust, even with two presilencers and an RB universal muffler. It's sort of unbelievable how effective a turbo is at noise reduction.

 

Sorry to be dense, what's an RB muffler? Is that a brand name? (google search sends me back here!).

 

Racing Beat. Specifically, this muffler will bolt on to your car:
http://www.racingbeat.com/RX7-1975-1...sts/16433.html

Lucky for you, you have an '82, which uses the same Racing Beat muffler as the one in their "streetport" long-primary exhaust system. So you can get the muffler now, and if you want more power later, you can buy the header and center section and have a very nice complete exhaust system.

 

There's not much left stock on our '82 (I don't think) so that won't bolt up anyway. I'm thinking as cheap a generic muffler we can put on there, although the stocker isn't leaking but I can't imagine it's internals are still good as the thing sounds really bad. Just want to tame it a bit. Supposedly this has been street ported, shady history.

 

Hey, that's the exact parts I've collected for my turbo 12a... 3 inch RB presilencer and Magnaflow straight-thru round muffler. How loud is that?

 

yeah i've done the stock muffler by itself before and i agree it doesn't sound bad, but a cheapie generic muffler won't be any better.

the rotary opens and closes the exhaust port much faster than a piston engine, so the pulses coming out of the engine are A, supersonic and B HOT, which also means a generic muffler will live a short life.

for $20 try it, but don't expect it to work really well for very long.

 

It turned out precisely how I was hoping it would. Wish I had a decent sound clip of it. The RB presilencer mellows out the tone a bit, but with the Magnaflow it's still throaty. It's loud enough to make itself heard and sound really nice in tunnels, but not quite loud enough to annoy me on the freeway. Perfect.

Yours will (depending on muffler sizes) probably be a bit quieter just because it's a 12A. I also have pretty big exhaust ports.

 

[QUOTE=PercentSevenC;10833439]They do, which is actually why I went with a Magnaflow for my main muffler (with the "medium" RB 3 inch presilencer). I wanted it to make some noise!

There you go! I have open wastegate though too . So it screams at full boost, while cruising I no longer have to worry about cruising by cops haha.

Id go with RB universal or some other nice universal OP like borla, magnaflow. Something that will last.

 

Awesome, thanks. All my piping is going to be 3" but the muffler is one of the smallest 3" mufflers that Magnaflow makes, so I'm counting on the presilencer and the turbo to take the edge off. As soon as it is done, I'll post up videos. Hopefully before it gets too cold to drive it.

And for the OP... sorry to thread jack. Straight pipe is very loud, far too loud for the street! It'll give you a headache, especially driving on the interstate next to a concrete wall. And your neighbors will hate you. I would go with an RB presilencer and muffler as others have suggested.

 

strait pipe cant be that bad, i went from a stock 12A through a basic RB system to a ported 13B running dual unmuffled thin wall 2" all the way to my old RB dual inlet muffler (muffler looked pretty empty if u look in through the dual tips...no packing at all) and it only got marginally bassier. normal driving isnt that bad...it only gets a lil loud when under a heavy load or 4k rpm and up, but it definatley sounds "rotaryish" gunning it up to 8k+

 

You wouldn't be able to see the packing even in a brand new RB muffler. And yeah, RB mufflers work fine without presilencers. The presilencers are mostly for tone anyway.

 

Assuming the stock muffler is still intact, can we attribute the really terrible sound to the lack of a cat which was replaced with a generic glass pack (which may have lost it's stuffing a long time ago)? I just want to help my kid shut his car up a little bit as cheaply as possible. Sorry this is a hijack by now isn't it? Oops

 

Your exhaust is probably busted. Unmuffled cars just sound like ****, period. I ran my turbo with an open downpipe for awhile, and even with the turbo helping out, it sounded like ***. You're going to have to be creative to make a NA rotary quiet. Most go with the RB mufflers, but they are restrictive. I wouldn't recommend them to anyone with radical porting or a turbo.

 

[QUOTE=twinkletoes;10833936]For sure dude. I like the way it sounds stock to lol