Why?
Thinking that my 8 was a little too quiet, and that the OE muffler weighed a boatload... I decided to have a conventional oval muffler installed to save a little weight, add a low rumble for 0 - 4500 rpms, and give a smidge of HP.

What?
Pro-Tech Automotive of Jacksonville did a very nice job installing what I believe is a PN 11226 Magnaflow 14'' L x 9'' W x 4'' H aluminized, 2.5'' I/O, offset/center muffler with a single RR exit and SS black/chrome Ractive oval tip. The inlet pipe was adapted to a 2.5'' mandrel-bent pipe at about where the OE slip-off flange is located. $250.00 out the door and a lifetime warranty for the muffler.

The result?
UNBEARABLY loud. Anything over 3000 rpms is ridiculous and forces me to short-shift to avoid the drone. Good thing this thing has Bose. And I LIKE a decent aggressive exhaust, growing up around open header drag cars. But this might not even meet decibel limits for some autocross or racing venues. I assume the result would be similar for just about any mid-priced turbo muffler of similar dimensions.

The lesson learned?
If you use your RX8 on the street, or otherwise race at a "quiet" venue, consider the seemingly way-too-big Racing Beat or Borla-cat back, or at least use a conventional oval turbo muffler longer than 14''. The OE muffler is ridiculously heavy and very big, with dimensions of 30'' L x 11.5'' W x 8.5'' H.... but there is a REASON for it...

 

This one passes sound at SD (which is very stingent): https://www.rx8club.com/rx-8-racing-25/single-side-exhaust-59424/

 

No highs, no lows... must be Bose?

In all seriousness, the Borla Clyde has on his car (the ULLLOSE exhaust) is pretty quiet. It has a bit of a drone around 60MPH in 6th gear, but to me it's not bad at all. You might try a muffler change.

JV

 

turbo muffler, thats part of your problem, are you saying a muffler for a turbo car, or thats just a brand? from my experience turbo mufflers is what we call a straight thru muffler...usualy a peferated core in a housing filled with sound damping...the problem is these mufflers are designed for use on a car with a trubo, since the turbo will quiet the exhaust note down a bit, so they can benifit from less back pressure since they dont need as much sound-deading.

When you put them on a NA/super charged car...they become incredibly loud, and when you put them on a rotary, where the exhaust pulses are stronger and closer together...see ya later ear drums...its insane.

 

The Borla we are using is straight-through, perforated core.

Really the determining factor is perforation density and muffler dimensions (length and outer diameter). Bigger = quieter.

JV

 

well it just depends on the muffler, those turbo mufflers are generally made for the muscle car crowd and those guys like 'em loud

my straight thru racing muffler is quieter than the oval turbo mufflers

 

Teamrx8-
What kind of muffler are you running? How does it compare sound level wise to the Borla's? (i.e. ULLOSE's car)



Thx-

Chops

 

I think it's a Borla muffler thing; always a little quieter, never tinny, a bit better made. And Isley's was a bit longer, at 16''. Can't have a conventional side-inlet oval muffler much longer than that without some CRAZY inlet pipe bends... remember the stock muffler has it's inlet at the center, and there it has about 15'' of girth toward the RR bumper.

I guess it's not a bad thing. If it makes me use less throttle and rpms, maybe I'll get better mpg. Last two tanks were clocked at 14.4 and 13.9...

 

http://burnsstainless.com/UltraliteM...temuffler.html

it's a 2.5" ID x 4.5" OD x 17" long

clyde has the same setup, he indicated in another thread he thought mine was quieter at an event than his, but to be honest it can be boomy inside the car at certain throttle throttle ppositions on the street, it doesn't see much use there though, if you have a daily driver and do competition you might want to consider ponying up for a Ti aftermarket exhaust