""I am assuming the longer (12" vs 22") the better or not?""

You want to try and add the largest (diameter & length) muffler that you can fit into the space.

Magnaflow makes 4", 5", 6", and 7" diameter mufflers for that location.

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

I would contact Accurate Exhaust in Roseburg, OR and get their advice.

I was confused in the terminology so I asked a Magnaflow Tech to tell me the difference between a muffler and a resonator. This was his answer:

""Mufflers and resonators are one in the same. We use the term resonator when two mufflers are used in line of one another."

When I pulled the original style resonators off of my Challenger, I was surprised to see a "straight thru" design. It was an oval shape so it would have more noise suppression than a glass pack type (round) style of muffler in that location.


The round straight-thru mufflers will not have as much noise suppression as the round "chambered" style. The chambered style will be more restrictive than the straight-thru style. So it depends on what you are after. The space that you are wanting to add a muffler is very restrictive, so a round muffler is about your only choice.

I have read that when trying to stop a droning noise, a second muffler (resonator) is used to break up the sound waves. Adding the second muffler will also change the sound depending on the selection of muffler.
If you want to change the sound of the exhaust a lot, then you may want to start over with your existing muffler selection. If you want to quiet down the exhaust a little bit, then adding the second muffler may do that. Then the type of muffler will then determine the final loudness and the performance level.

It appears that you might end up with two mufflers per side due to the size of the exhaust, the size of the engine, and you do not want to lose performance.

Yes, I like the Flowmaster sound but just too loud! It also seems to hit a perfect resonance in the cabin right at 60 mph or so where it just makes my head want to explode.

I am fine with adding the second glasspack/resonator on each side. I just don't have the money/time to experiment with multiple sets of mufflers here.

If my main goal is to keep the sound but quiet what I have the most (eliminate drone), what do I do?

A glasspack on each side behind the tips (if you have tips) will calm the noise down alittle more and it takes the drone out, there are a lot of people I know that use glasspacks as resonators.

Probably 18" glasspacks would for sure do what you want it to. They are usually 3 1/2 to 4" diameter shells and come in sizes from 12" to 36", the longer the quieter it will get which will help get rid of the drone, but like I said which ever the longest you can fit beside the gas tank.

Would these reduce the noise quite a bit? I think I should be able to squeeze these right beside the gas tank.

http://www.summitracing.com/parts/mpe-18129/overview/

yeah those are the 18's, just remember that it will make the overall exhaust sound alittle quieter aswell.

I have not looked under a B-body like yours but I would be surprised if you could not fit something larger than 4" round. You will want the largest resonator that you can fit in my opinion. The mufflers/resonators are still a straight thru design, so I would never consider them "quiet" with the size motor you have. I sent you a PM with info on the shop I used (rjscustompiping.com) here in Raleigh. My suggestion would be to talk with Ron and let him put your car on the lift and tell you what he thinks will fit.

If the Magnaflow tech said mufflers & resonators are the same thing, that could be true sometimes, but also not true a bunch of the time. If you were going to run a muffler & a resonator in the same system or bank, the muffler would not need to be straight-through, but resonators are always straight-through. Resonators should not add more restriction to a system. You could use Ultra Flows as resonators, glasspacks, Corsa, etc. - as long as they are straight-through. Beware though, many glasspacks downsize internally & that will build backpressure. On your Charger exhaust, you'll have room for 18" long body & 4" diameter - maybe a little larger diameter. On the noise control package from the factory on these cars, the resonators were 4" round & the bazooka tips connected directly to them via sheetmetal screws. I did a very similar setup on my '73 Rallye 340 car using Walker 4" round mufflers - see photo.

Ok guys,

I went ahead and ordered the 18" Magnaflows. I may not get them on now as your picture just reminded me that I need to get a set of the bazooka tips for my Charger and that will dictate where the Magnaflows need to go exactly.

When I have some spare money and this car is running somewhat reliably, I will get these so I can have everything put together at once the right way.

Thanks guys! I am hoping this will kill the drone and quiet down this exhaust somewhat.

Not sure what kind of power you are making.. could consider going to a 2.5 or 2.75" tail pipe. That will help too.

here is my car with Dynomax turbos (tti system)
https://www.youtube.com/watch?v=to0Z2Z3GqD8&feature=youtu.be

I have 40 series Flowbastards on my Charger also & got sick of the resonation while driving. I added the 18" Dynomax glass packs to the tail pipes like the factry resonators & man what a difference. So much quieter, no more resonating & my ears don't ring for hours after driving it for awhile now. Wish I would have done it years ago now.