I have an interesting muffler now. I did the muffler delete on my 2006 Hummer H3 and it sounded okay, but when I drove it there was a terrible drone at 2500 to 3000 RPM. Take off and passing improved a lot though, but the drone was unbearable. I wanted the improved performance, but without the noise.

From the Moroso website-->
Features:
Reduced noise levels with minimal back pressure
5-7 db drop over open collector headers
Flow 850 cfm

I've been driving it for a week and couldn't be happier. It' sounds great, low tone and no crackling like a glass pack would have. It's not too loud and there really is an increase in performance over the stock muffler.

 

It sounds like a rice burner..

 

Nope that's the cheap camera mic. It's actually a lower tone.

 

I have a 7.1 200w surround sound connected to my puter, and your mic works fine. I can even hear a loose heat shield on your engine.
Your muffler sounds decent at idle(vibrates my walls), off idle it sounds like a rice burner.. Makes that H3 sound wimpy...JMO

 

With the I5, whatever you do to exhaust post Cat by itself is only going to get you sound, not any measurable performance boost.

Now, if you add a, Intake, PP TB, PCM Tune, and Efan conversion with that mod, you might attribute 1-2 HP/TQ to the exhaust mod. More theory than anything.

Low tone sound is cool, beats the crap out of vacuum cleaner whoooosh.

 

Yeah I've got your Intake. I'm going to do the PCM Tune, but probably not the other stuff.

I would swear when I cut the muffler off it made a difference in takeoff and passing. Installing the Moroso didn't hinder it much. Maybe just a hair.

 

I believe you are actually better off with the muffler than without one, a bit of back pressure is not a bad thing.

 

wouldn't the cats provide that backpressure by themselves?

 

I thought they would and I also have the resonator on, and all the bends in the piping, but I'm pretty sure my fuel economy dropped (possible consequence of not having back pressure or too hard on the pedal). Who knows. I had to add a muffler, the drone was more than I could bear.

I wonder if I cut the pipe as it comes over the axle and ran it straight out the back if I would have had that terrible drone. I don't think I'm going to play with it anymore, so I won't know for sure.

I just took a 200 mile trip with it and it's louder than the stock muffler, but not annoying to me. I like it.