Dennis Burford

Hi guys and gals,

I had a local muffler shop fabricate an RMB for my 86. Still running cats and mid resonator. She's a bit too loud, and blappy on WOT, and poppy on deceleration. I love the look of where the tips sit now, and the loss of a 40 lb pumkin, but would like to tame the noise and smooth it out just a bit. Looking in the archives, I've not found anyone who tried taming the RMB with a high flow muffler in place of the midway resonator. If you've tried this please let me know your results and thoughts. All comments welcome.

Mongo

You can replace it with a dual in/out Flowmaster 40 Series Delta Flow. The Delta Flow is quieter.

Dennis Burford

Thanks Andy. Have you done this to your S4? I don't want it to be too quiet, not as quiet as stock, just want to tone the sound down a bit and even it out now.

Mongo

Very True! I have 10 series which are single chambers and I have to put resonated SUV/Truck tips on mine to quiet down the resonance at cruise (who cares on WOT). However, it's actually surprising how that little delta chamber in the middle quiets down the drone. Here is a shot below.




Now here is the original 40 series Flowmaster. Note the difference.

Dennis Burford

OK, no loss of air flow but more baffles for noise reduction, looks good!

PorKen

Welding in a balance (H) pipe before the tips will mellow the sound somewhat.

bcdavis

Yeah, I did the same thing on mine. I replaced the rear muffler with just tips, and it was too loud and raspy. I think the earlier cars had less "mufflerey" mid-mufflers. I've heard late year 928s4s with RMBs and they sound awesome. But not always true with the older cars. I thought the flowmaster sounded good. Here is a clip:

http://www.youtube.com/watch?v=yHE9hnoV4EY

Dennis Burford

Wouldn't the two into one muffler anf back out into two pipes act as a balance pipe? Decision made, I'll have the shop weld in Flowmaster 40 Delta flow in place of the stock resonator.

Landseer

You can fit a small dual in, dual out Magnaflow where the pumpkin was instead of the RMB.

It will need a little custom tip work though, to bring the discharge tubes closer together and to tip them.

Speedtoys

I did this just last week on my S4.

This all fits to the X pipe.

Dennis Burford

Jeff, very pretty!

Speedtoys

Thanks..spent about three 5p-3a nights at the shop after work to get it done..with a little help to make sure all was straight. I can prep & weld really nice, just needed the geometry help.

Dennis Burford

My next tool, wire feed welder, saving my pennies....

James Bailey

That setup will have a very smooth sound given the x-pipe common muffler/resonator and one into two tail pipe tips. The uneven bank to bank firing gets all mixed up

Dennis Burford

BTW Jeff, LOVE your avatar. Friggin' hilarious!