Muffler Suggestions

[Bav3.5]

Does anyone have muffler suggestions for the Bav? There seems to be very few options. I would like a 2.5" in/out if possible and the only option i'm finding is a Magnaflow (#12646, 6in round, 18in body). However, i'm worried its going to be too loud. I would like something reasonably quiet. Any other options or experience? The car currently has a 3.5L, long-tube header, no cat, and a 26" Magaflow glasspack as a resonator going into a stock muffler (which is breaking apart and rattling inside). Will there be a big difference between a 2.25" vs 2.5"? I'm not trying to squeeze every bit of hp, but any gain over the stock muffler would be nice.

 

[decoupe]

What are the dimensions of your OEM muffler? Try to find something close in terms of volume for the same sound level. The CS uses roughly 6 x36 and I went with a 5x8x24 oval Magnaflow which is very close to the same cubic volume. Here's a link to Sven's post on his SS 2.5" system with a lot of background info from Pamp on the choices - I'm doing something similar (hope some of this helps you).

http://www.e9coupe.com/forum/showthread.php?t=12668

http://www.magnaflow.com/02product/universalmuffler.asp

The CS OEM rear muffler has a side inlet and the Magnaflow 5x8 oval has inlet and outlet both on the ends so fitting requires some interesting pipe configurations even though the can is almost a foot shorter.

Doug

 

[Mike Goble]

I'm looking at a similar setup for my Bav. I have a stock setup right now, with the glasspack under the car and a stock muffler in the back.

I have a set of 1-1/4" Stahl headers with 1-5/8" collectors which will be going into a Columbia 1-5/8" x 1-3/4" parallel merge collector coned up to a 2-1/2" tertiary pipe. I'm looking at a Walker 24236 for the resonator and a Walker 22138 for the rear muffler. The 22138 is stock on '80's Jeeps and is used by itself with a cat. I may forego the resonator and put just the muffler and see how it sounds. Walker 22635 is also 2-1/2" I/O.

Walker specs:

http://www.walkerheavyduty.com/catalog/docs/WHD08_MufflerSpecs_by_InletSize.pdf

As far as the difference between a 2-1/2" tube and a 2-1/4" tube, it's about a 25% increase in area from the smaller to the larger. Small changes in tube size make large changes in area.

 

[Bav3.5]

Just as a follow-up, here is what I ended up with:
Magnaflow 12646 (6" diam, 18" long body), Magnaflow glasspack (4" diam, 26" long), 2.5 in piping with mandrel bent tail pipe due to the tight bends.

Observations (and my rough guesses) compared to my stock 40yr old muffler with the same 26" Magnaflow glasspack:
-idle is ~20% louder
-cruising on the freeway is somehow about the same with no drone at all
-accelerating normally is ~25-30% louder
-accelerating hard is ~50% louder
-less torque on the bottom end, but with better breathing and a gain above 4k (I think it maximized the potential of the long-tube header)

I've read on e28 forums that this muffler can be really loud, but I think the big glasspack really helps it out.

Thanks for the comments and suggestions earlier.

Tim