Originally Posted by
Kennedy
In my opinion, a cat back system is not worth the money. You will not have near the sound quality (whistle) that you seem to be looking for.
I sell a LOT of front pipes to guys who started off with cat back purchased elsewhere and wanted to upgrade...
Factory air box on the LBZ is also tough to beat.
I have a 4 in MBRP SS downpipe back exhaust in my LBZ. When you get on it, you can hear it and others hear it to
I keep thinking about a CAI and read how good the stocker is, but the air seems warm going in. It read 70-80* today with outside air being around 60 or less. This is via a new Evolution which I like so far very well.
I did round out the sharp inside edge on the intake and put a AFE filter in it. I can notice no diff between it and the stock filter.
My milage was better a few months back, but has gone down lately. I was getting 18 or so with a light foot with mixed driving, now I am getting maybe 16.
I went to LV (600 mi ea way) and averaged 18 going down and less than 13 coming back. I was towing a 20 ft enclosed 2500# trailer under 65 all the way back and was very disapointed in the MPG. This was all with a Diablo 65 HP economy tune. I went to the Evolution for ease of setup and the gauges even though I had a Qudzilla Recon already.
One thing I noticed is the mileage seem to turn down after I did the turbo down pipe. I really don't want the cat back on, but could it really affect the mileage that much?
2006 GMC D/A C/C S/B, Snug Top Shell, Bed-slider
33 inch Toyos, 17/8 Pro Comp Wheels, 4 in SS MBRP Exhaust-Turbo back, Evolution Tune, Mag-Hytec on Rear and Trans, Tranco Jr Shift Kit.