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Discussion Starter #1 (Edited)
I'm looking to get as much speed from my Commander as I can. I have a CAI, ported throttle body, and now I need to complete the air flow with a good exhaust. But I don't want the exhaust to be loud at idle (my truck had a loud idle And my neighbors didn't like when I'd leave it running in my driveway cause they could hear it)

I have the 2007 4.7

What exhausts do y'all have? What kind of sound does it make and how loud is it? Any power increases?

Thanks. I've already looked in the sound clip thread but half of them won't load for me ha

-Matt
 

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I am not sure how long of a muffler will fit under the Commander. But I am assuming there is some space. My personal experience:

The Dynomax Super Turbo 17748 would be what I would recommend. I can't speak to it on the 4.7 but on a Chevy LT1 with a mild cam and true duals it was barely louder than stock exhaust but with a much nicer tone under load. That application is the offset/offset version (part number 17749) but otherwise identical. This was the setup on my Dad's Impala SS

http://www.summitracing.com/parts/wlk-17748/overview/

My brother wanted the "flowmaster sound" without getting too loud. His car was a retired cop car; A caprice with the same mechanicals as the Impala SS and this one was stock. The flowmaster 70 series big block gives you roughly the same volume level as the Dynomax but with a sound that is more of a growl that Flowmasters are known for. What they are not known for is flow. The Dynomax will outflow the Flowmaster and give you more power.

http://www.summitracing.com/parts/flo-52571/overview/

I personally had a LT1 caprice with just about every bolt on you could do plus a REALLY aggressive cam. It put 343 hp to the wheels through exhaust cutouts. For mufflers I tried Dynomax super turbo's (not the long case) and they were too quiet for me, I tried Flowmaster 40 series Delta Flow and they were not the sound I was looking for. I ended up with Dynomax Ultra-Flow's and I loved them. I would not recommend any of these if you want near stock volume levels though.


I know it's not 4.7L related or even Jeep/Chrysler related but it should get you pointed in the right direction.
 

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This is old, but I am hearing good things about the dynomax vt

REviews years ago were mixed as they had issues with the valve rattling. No longer appears to be the case.

Quiet at idle, a valve is actuated by backpressure and it becomes a straight through muffler, I know that from the factory the corvette had a similar setup for certain years/options...

http://www.jeepforum.com/forum/f9/dynomax-vt-muffler-1250698/

Ah, a similar review on this forum:
http://www.jeepcommander.com/forums/showthread.php?t=18140

I am heavily considering this route...
 

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I am not sure how long of a muffler will fit under the Commander. But I am assuming there is some space. My personal experience:....
The Commander has the Gas Tank on one side and a very long muffler on the opposite side. So the dual exhaust is only dual till it gets to the single very long low restriction muffler with a single tail pipe.

So there is no room on a Commander for the traditional "dual" exhaust, where there is exhaust piping going down each side of the vehicle, on the Commander it all has to run down one side of the vehicle.

Before you get into moving the gas tank, it won't fit anywhere else, maybe you could spend tons of money (more than the exhaust system itself) to find a new spot for the spare tire, and put a custom gas tank in the spot the spare tire was. Then you'd have to live with the constant check engine light (CEL) being on, because I doubt you'll ever get a custom tank to replicate the evap emissions test results of the OEM tank and thus it will constantly have a CEL for failing the evap emissions test, even if you have the custom tank properly working with an evap emissions system.

So, a lower restriction muffler would improve performance, but NOT as much as a true dual exhaust with two low restriction mufflers.

And someone had a link on one of the threads with a picture of a true dual exhaust setup on a Commander that runs down one side of the Commander and fits two mufflers within the generous space for the single muffler.

It used two shorter low restriction mufflers with offset in/out pipes, so you stagger the tow mufflers, one after the other, using the offset in/out pipes to the muffler (i.e. one muffler flipped over) so the two pipes run parrallel, while matching up to the in/out pipes of the mufflers without having to make massive bends in the pipes. Then custom dual tail pipes over the axle to exit in the rear all on the same side.
 

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This thread may be a hair past it's prime, but I have a video clip the OP might be interested in if they haven't made a choice yet.

This is the Dynomax SuperTurbo mentioned earlier on a 4.7L Jeep ('04 Grand)

https://www.youtube.com/watch?v=5-uuj7S746g&list=UUE5GWXc4nf5Y3o374kqC1Mg

At idle, it was barely noticeably louder than stock, and at highway speeds or under light acceleration, it was likewise barely noticeable. I wanted something mild but with a little more grunt. I ended up swapping it out for a flowmaster 70 because it was too close to stock in sound level. The SuperTurbo is one of the highest flowing designs as far as mufflers go, and probably the quietest low restriction muffler you'll find. Not a bad sound, either.
 
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