After messing around with both Flowmaster and Spiraltech mufflers on my 03CC, I finally got smart and upgraded to the 4" MBRP exhaust last fall. I was happy with the improvement, but had a little drone (OK a little drone from the exhaust and a lot of drone from the wife). Last night I added the front pipe and resonator. Wow! Mark Craig and the guys at DPPI have really got this system dialed in. It fits, looks and sounds great, has no drone in the cab and provides improved throttle response. I'm sure the EGT's are lower, too.

To do it all over again, my first upgrade would have been a complete 4" exhaust, including the resonator. I cannot believe what a difference it makes. :)

What was the problem(s) with the other brand mufflers?

Dan

Fred G<

Excellent Fred!! Glad it worked out as expected, we've done that set up a lot and it does the trick everytime, enjoy it and have some fun!!

Mark @ DPPI

The flowmaster was a direct 3.5" replacement for the stock muffler. It helped decrease EGT's, improved turbo response, and the truck ran great, but also had a "medium" level of resonance across most RPM's. It wasn't bad running empty, but was irritating when towing.

I then tried a 3.5" muffler from spiraltech. It didn't flow quite as well as the flowmaster, and was generally quieter, but had a bad resonance around 1700-1900 RPM's. I added the poor man's resonator fix (angle iron strapped to the front downpipe) and it helped, but didn't fix the problem.

The MBRP w/o the front downpipe was a definitely quieter than the flowmaster but still generated some low-frequency resonance at certain RPM's. Now that I've added the frontpipe, the resonance is 100% gone.