Interesting. I also had the HFC and two mufflers were quieter than the cat + muffler option. I was running a 6" center muffler and Buschurs 7" rear. Were you also running a 6" muffler in the center or smaller?

 

lueevoix, are you still running the stock cat back? Happy with the setup?

 

This is the setup I've been running for a year now:

https://www.evolutionm.net/forums/ev...y-muffler.html

 

 

Well, I sold the Blue Evo IX back in Oct 2012 . I currently own a 2003 WW Evo VIII . I had Buschur SD Muffler, Varex Muffler and Electric Exhaust damper. But now I decided to part out the entire Power Train assembly and turn it into a “Tesla” .

 

 

^Sorry , let me clarify . I had 3 different setups not all three in one .

Originally when I bought the car it had 3” catless eBay or Megan exhaust. It was loud as heck and a big pain driving it from Alabama to Illinois.

I figured this was not going to be a daily driver and got the buchur SD rear muffler. It was still really loud for my taste.

Next I got the Exhaust Damper and Varex muffler. I tried each separately . The Varex muffler made the car stock like quiet . quietest setup I have had. The damper quieted it down but not as much as I would like. It was a cutout like type valve that was a 2 bolt flange and worked in line with the exhaust not dump.

For the most quiet setup and retain 3” flow during WOT, I say just get a Varex muffler .

 

bumping this for 2019! so i'm still running the 200cel cat, 4x20 muffler and a 5x8 muffler before the exit, basically a hacked up buschur exhaust at this point with larger mufflers bolted on... and I still want quieter. any tips for this? the varex seems nice but I had an electronic cutout on the M3 exhaust and it stopped working.. while stuck on the "open" position. don't care about power, want quiet when cruising.

 

How long is the 5x8 muffler? Try a slightly larger on? Or longer?

Also, if they're magnaflows, I have found magnaflows don't stay quiet on my car, at all. They go like 6 months and then they're done. So I gave up on having a quite car.

Maybe try the Tanabe Medallion Touring exhaust, it's pretty quiet.

 

hmm hadn't considered magnaflows going "bad" though it's not that old IIRC. it's 14" long, so 5x8x14, and the 4"x20" long muffler right before it.
I've had a tanabe medallion, i didn't find it too quiet. I reach out to RRE to see if they still make their exhaust, could be a decent market for it given the new laws. I think what it boils down to is I want silence in my car and I'm not going to get it in this chassis with a 3" exhaust.

 

The RRE stealth is pretty quiet. What you're running into is drone, which requires the resonator to be in the right spot. Which the RRE stealth has that. At least in the car I rode in with one. The CT0a is, in general, loud on the inside though. Road noise, engine noise, drivetrain noise, etc.

 

I had the RRE , its pretty heavy compared to many of the exhausts (catback) i have used. I believe they made it out of mild steel or 316 SS not 304. Also it was not as quiet as people make it seam. If you want stock quiet it is far from it but quieter than most. Just keep in mind, i was running it with 3” downpipe and resonated testpipe. (no Cat)

I learned that if you want to get close to get stock quiet then you must use something that will hurt flow. So only way to make power and be quiet is to use some sort of baffled muffler and a cutout of some kind. Varex muffler does the job pretty well. You could also run oem muffler or something close to it and add a boost actuated cutout behind the muffler, next to or were you please.

Something that comes to my mind is exhaust tubing diameter. What if we ran a dual exhaust tube catback? For simple calculation purposes the area of a 3” circle is approximately 7.07 . The area of 2.25” diameter circle is 3.98 . If you have two 2.25” diameter circles shouldnt it be equivalent to (7.96) around a single 3” diameter circle ? So if this is true with fluid dynamics then running dual 2.25” catback exhaust will flow approximately same as a single 3” exhaust? Unless my theory is completely off and it doesnt work this way?

I’m assuming dual 2.25” exhaust tubing will be quieter than a single 3” . So why not run dual 2.25” exhaust catback with straight flow mufflers of some kind of size and length ? Maybe even add in an x pipe or h pipe in the mix?

What you guys think ? I’m not an engineer so its possible I might be way off or other variable involved i didnt take into account. I understand there might be some sort of slight loss from the transition or possible additional friction the exhaust traveling in the piping. But if it will make a significant difference and only slight 5-10 whp difference on a 500-600 whp car it may be well worth it.

 

idk if that's going to be "worth it." interesting that the RRE isn't all that quiet. I guess coming from a double muffler, probably marginal in terms of sound.

i think that's more or less it for me then. i had an electronic cutout on my m3 - like i said, it stopped working - stuck on the LOUD side, bypassing the rear muffler. jeez. it was great when it worked, sounded awesome, but not worth the trouble.

 

By no means is the RRE factory quiet. It has a rumble to it, especially with a 200 cell cat. Inside the car, you can hear it. But at the same time, it's probably one of the quietest aftermarket systems out there. Put it this way, it's an exhaust that you can hear but not loud enough to draw attention.

 

Like @BluEVOIX said it is loud (RRE Stealth) in the sense that it produces a lot of low pitch sound that seems to carry farther than the high pitch sound. I was surprised how much bass it has compared to stock.