Quiet Muffler?
 

A guy I prep a car for is tired of his ears ringing after driving his track RX7. The car has a 12A street port, Weber 48, short primaries, basically a nice EP set up. He isn't racing the car so losing some power isn't a huge issue.

I'm looking for a quiet muffler to hang on the back of the car. 3" exhaust right now, the car has a dynomax bullet glass pack style muffler ahead of the rear end then a mazdacomp stainless out back.

At this point the car is parked and he is driving his supercharged Miata in events. We have a Miata parts car laying out back and he says, "Let's put the Miata engine in the RX7 so it will be quiet, I'm not driving it with the rotary anymore" I tried to tell him that's crazy talk, let me change the exhaust first.

RX7 1986-1992: Exhaust - Complete Systems: REV TII Presilencer - 87-91 RX-7 TURBO II -

ive had good luck with that. since its a 12A you might consider a 2.5" muffler too, in the rear it should flow enough, and 2.5" is much quieter

I Dont use anything else these days... Flowmaster Hushpower


Flowmaster 13016101 Flowmaster Hushpower Pro Series Mufflers


Do your research on them. The design behind them is solid. Best I have found...

I have a dual 2" long primary system that will fit the car. It used to collect into a three inch right around the rear end and go into the mazdacomp muffler. I'm going to try to get him to let me experiment with a couple different smaller dia pipe mufflers with the long primaries. I can pick up power with some bigger venturis, I think it had to have 40's for EP and I have some 42's in my collection.

For a brief moment last night I thought to myself, "I know, I'll put a turbo on it. That will quiet it down.":nod:

I'll see what muffler is on my car, because it's only producing 88db down the back straight at Road Atlanta....lol.

actually Peejay is running a power pulse on his car, and its expensive, but its not restrictive and he's on a bridge

Can't really go wrong with the powerpulse. My car is too damned quiet! :)



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Yeah, it's very quiet, although at the last rallycross I was running the engine extremely lean, about 1000rpm past the point where the injectors go static (wouldn't rev any higher than that... hmm) and I burned out most of the gasket material at every flange, so it's gotten a bit louder.

Compare 2.5" exhaust with 24" long Thrush in the middle and Dynomax SS at the rear:

[youtube]fVYWleeCrfc[/youtube]

To same engine, with RB long primary exhaust:

[youtube]-rZAnwUd6kE[/youtube]

Power output did not change. Engine was a half bridge ported GSL-SE engine with a S4 intake. The new engine is much better on the intake side and has much more overlap involved. It likes the new exhaust just fine.

2 Borla XR1's, done.