I am curious whether the exhaust layout on the RX-8 could support a center-exit exhaust, like Ab-Flug's FD3S. I know these two cars are different, but would you rather have me use a 2002 Camaro SS? Overall, would a center-exit exhaust help or hinder performance? I was thinking about using a chambered muffler, since they flow quite well and they're relatively quiet.

 

if you mufflered it and then brought the tips back to center, you likely lose power, as theres no other way to mount a decent sized muffler except parallel to the bumper and you have alot of unecessary bends. if you went with a straight pipe right out the center, you have about a straight shot straight from the exhaust ports, so you'd get the max power.

 

... and max NOISE...

 

yea.. w/o the muffler.. it'd be freakin ungodly loud...

 

Has anyone used a Supertrapp muffler yet? Or are they not any good? They always sounded really nice when I heard them on Mustangs, but I don't recall seeing one in a while.

Maybe you could mount one in line with the car, right down the middle, coming through the rotor shape in the back bumper. You'd have a straight shot down the middle of the car with hardly any bends whatsoever. It looks like there's enough room for one single muffler/tip, which saves money and weight ( the 14" is 5.5 lbs. according to Supertrapp). Just buy one muffler and let your local muffler shop do the rest, I'd imagine. Plus you've got something that's tuneable.

I'm not a huge fan of the way they look, but they have this version, which isn't too bad:

 

Thanks for the tip guys . I guess that's why Mazda didn't opt for a center-exit exhaust. It would appear to me that the car's underside doesn't have much room for exhaust system flexibility. I'll check and I'll be right back .

 

Crap .

 

Well anyways, after checking, I don't think there's any room for even a side-exit exhaust. That's okay though. I'm waiting for the RB exhaust. No girlfriend=more money :D.

 

well in response to your inquiry on performance gains...it all depends on where you plan to go with it..

for instance if you want a center exhaust exit for looks and performance it would hinder performace on a N/A application due to it HAVING to be just about as straight as you can get it...this will result in loss of back pressure which is needed on an N/A engine, in small amounts..

now where the performance does come in to play is where a straight piped (not non-muffled just straight in it's application) center exit exhaust would be the most applicable in a FI engine..you want the least resistance and max flow available, minimizing the bends to create the most power...

 

You guys are thinking way too hard. It would be simple. This is something else that I have planned to do but need a car in my posession first. The rear bumper would have to be refabricated since only the exhaust tip shield pieces are removable and not the entire lower black part. I would remold the stock appearance but in the center I would have 2 tips. The stock outer locations would be rotor shaped accent pieces. I would use 2 Corvette style mufflers from Borla. These have their entry and exit points on the same side. Split the pipe with a Y and sent it to each muffler whci is mounted on each side of the car. The exhaust pipes then turn 90 degrees again and exit the back just like a Corvette. The exhaust system would be the easy part to do. The hard part is reworking the bumper.

I know that people are going to say that the 90 degree bends are going to hurt performance. That may be technically true in relation to flow through a straight pipe but it the main exhaust restirction isn't at this point and these still outflow the rest of the exhaust, the bends are irrelevant. If we take a single 2.5" primary pipe and seperate it into 2, 2.25" pipes, we have a huge total area increase. This slows the air down and makes any restrictions "effectively" less. There isn't a single RX-8 cat back exhaust on the market that gives impressive gains. If this doesn't either, it will be no diferent than anyone elses. With more total flow area, it shouldn't make less power.

Yes, it can be done. "formerly shelleys_man_06", I pm'd you about this topic.

 

check this out
https://www.rx8club.com/showthread.p...threadid=33285

 

Well, that doesn't really explain much about what I was talking about mikeb. If you want an idea of what I want, check out

www.ab-flug.co.jp

If you navigate around, you'll find their FD3S RX-7, which has the center-exit exhaust I am interested in, sans the dual "ricer" mufflers. I couldn't find a technical name for them. Maybe rotarygod knows...

Anyhoo, if I do go with this experiment, I would use RG's method of using the Dynomax Corvette muffler. Even if this thing is made, I'm concerned about the excessive noise. Not only do I live in a relatively quiet neighborhood, I have to commute to school 80% of the year. I would dread driving a car that has a droning exhaust note. Trust me. One of my friends owns a Chevy Cavalier with a coffee can muffler, and the noise is awful. If I duplicate the sound with the RX-8, not only would it be much louder, but it would be just as good as if I owned the J-Body. I hope my friend isn't reading this . The idea is mostly for aesthetics. But, my real focus is to extract more power from this engine, as well as add greater balance to the car. I wouldn't want to waste unnecessary dollars on aesthetic pieces. I'M NOT RICH .

 

that was my whole point to my post...and if I read RG correctly as well...you won't have any gains doing this...it will be purely aesthetic...i mean just like RG said...none of the current aftermarket cat-backs are providing any significant gains...so this wouldn't either..it's essentially the same exhaust setup that is running right now just routed differently...what _I_ was referring to was eliminating the Y pipe and having a single exhaust run, this coupled with FI will give you your performance gains...not by itself...no exhaust on this car alone will provide a significant enough gain to satisfy everyone's thirst for more power/torque...

 

Agreed XeRo. I think exhaust tuning for the RX-8 has reached its peak, at least in N/A form. I checked out MazdaManiac's write up on the CAN-OBDII coupled with the e-manage. There's much better power to be extracted from the PCM. For now, I guess the only good power can be found in playing with electrons.

 

had exatly the same idea when i got the 8 about 12 months ago.
all you have to do is get the muffler/exhaust shop to fab a muffler with a centre exit exhaust tip (sounds simple, but it'd have to be custom made) that comes out throught the rear rotor symbol thingy....
did get to do that because i got lazy and got busy with other things..... :D