Hey guys,

We are a chumpcar team running a streetported 12A and have been having troubles with sound requirements so have been looking to change up mufflers.

Currently have RB race headers all the way back to a generic autozone special (we had much more open exhausts before but it got destroyed in a racing incident).

Basically just looking for some tips on what other guys are running for mufflers. The main ones I can find are the RB power pulse and the Monza system (but don't know how it does for sound).

Any info is much appreciated.

 

On our ChumpCar we are running a 3 stage system. We built a merge collector from the header flange to 3 inch, first up is a Schoenfeld circle track muffler that turned out to basically do nothing, then we put a Moroso spiral muffler that is actually very effective, both of those are welded to the collector. From there we go up over the axle and have a 3 inch Magnaflow turbo muffler in pretty much the stock location. This system works well and is pretty quiet with no packing to burn out. I would leave out the Schoenfeld and just run the spiral as a pre muffler if it wasn’t already welded in.

 

i have a Japanese magazine with a muffler test in it, and the results are actually pretty simple. the bigger the muffler, the quieter the car was.

 

I have plans to run Laguna Seca this year. With a 110 DBA limit.
I plan on running 2 Magnaflow SS 17" mufflers and normal Magnaflow turbo muffler.
It will have 1 of the 17" as a pre muff and then under the axle then the trubo muff a 90deg and the aft muff under along the back of the bumper.
Pros> very quite!
Cons> you get hit in the rear. your toast.

 

my PP car has a 3" borla on it, and only does about 103db, for 110, i don't think you need anything special.

for laguna you may want a tip you can angle, as the sound meter is on drivers right

 

The EP guys around hear use a 5" round Magna Flow muffler (for 3" pipe) at the back of the car with a turn down pointed away from the sound station. They run them with the stainless packing for about 3 race weekends or until the packing is gone. Then cut them open on the side and fill them about 3/4 full of lava rocks. They close the hole with some stainless sheet metal, high temp permatex and steel rivets. The lava rocks last many seasons and these mufflers have always beat 103 limits.

 

I use stainless wool on my 13B PP

 

What type of sound restrictions are in place for you? I figured that steel wool would just burn up as soon as the system is warmed up?

I've seen on the chumpcar forum that guys will pull the packing out of mufflers and put in lava rock and it seems that the overwhelming consensus is a multi stage system (or full racing beat) is required to be able to meet the 92dB requirement that is in place for Chumpcar.

 

I just run this last weekend. I was under 100 dba with just the SS mesh 12x4"" Magna flow round before the axle. Then a MagnaFlow SS mesh universal 12"x 6" oval Muffler (not a turbo muffler like I mistakenly said before). I'm very happy!

Although I did get pinched off in a turn. Thought they saw me when I stuck my noise in there. But with the old system. They would have heard me...lol.

I will have dyno numbers soon. I had 138 whp before with a single Dynamax 12 x4" round with a turn down before the axle.

 

I use some thing like this, the exhaust sounds pretty bad, but still pass the noise test
Be runing this setup for 2 years
Still hold fine