robertgreen79

I just installed the Rusty's axle back muffler and its great so far. A lot deeper than I wouldve thought. It uses a Cherrybomb muffler. The price was pretty good too

JK07

No i am not putting the muffler at factory muffler location. My exhasut is already setup with axle back muffler.
I am very happy with my entire exhaust setup interms of clearence and bends. All i want to do is replace a muffler which has some sweet spot back pressure.
My current muffler is straight thu and loud. I am not fussed about the noise i just need to aadd some back pressure for lost of torque if that makes sense.

Do you sell just a dynimax muffler which i can buy part # ???? Please

Slob

Thanks guys. Now I know.

Imposter_LRF

If you give me the OD of the inlet/outlet, the length of the muffler, and the sound you are looking for, I can hook you up with a part number sir! Our ultraflow mufflers are straight through, but our VT mufflers have a valve in them. The valve is passive and will open up to give a "straight through" muffler when under load, but in normal driving conditions it will be closed, in turn adding the backpressure that you desire.

However, I do not necessarily agree with your "loss of torque" from low backpressure. From Professor David R. Dowling (Ph.D. in Aeronautics, teachs experimental, computational, and theoretical fluid dynamics and acoustics in automotive applications for the University of Michigan) in my Exhaust System Acoustics and Backpressure Handbook (and training), "There is no 'optimum' cold end backpressure - less is always better" And... for naturally aspirated engines, "rule of thumb: 0.21% power loss per kPa of backpressure increase"

BTW, "cold end" refers to the "cat back" exhaust system.

tslewisz

The valve thing is a pretty cool idea. I guess there isn't too much worry about it getting gunked up in a modern FI/catalysed engine, but since it'll be pretty far back, I'd worry that a vehicle that does a lot of short hops might have problems with condensation/corrosion since it won't get hot all the way to through the muffler. Comments?

IMO, the cats will provide adequate backpressure.

Imposter_LRF

^^ That is why I said "cold end". Some people think that removing cats is a good way to increase power/torque, but based on camshaft timing, this may not be so, especially with VVT technology these days (Not applicable to our 3.8L).

As for corrosion due to condensation, its a good thing the valve and all internal components related to it are made out of 409SS (pipes), 409SS Nickle Modified (valve, more resistant to oxidation than normal 409), 316SS (wire mesh), and the springs is made of Inconel 718 for long life under temperature

BTW, this design is patented, therefore the usage (by non-Tenneco/Dynomax subsidies) of these materials in relation to exhaust system passive valve technology could be violation of international patent laws. Patent 7,434,570 Tenneco (10-14-08). (<-Had to write this stuff to let you know what materials they were made from)

JK07

Thanks for sharing the info. I am using stock pipes just cut from the middle axle back spot and added a stright thru muffler.

So that means i am good no need to replace the exhaust bec its straight thru

Imposter_LRF

Unless you dislike the sound, there should be no reason to replace

jeeeep

take a look at JBA muffler- part number I have includes some pipe, but contact them for muffler only part:

Part Number: 40-1509