Well, I've had my FloPro 2503 muffler for about 2 weeks now. I went on a 250 mile trip to the river (500 round trip) this weekend. Not towing I got 14.3 according to my DIC. I got 13.5 last time. Towing my 5000 lb boat home I got 11.1 - last time I towed I got 11. I don't know if it was muffler or the fact that I used the cruise more this time than last. Without the boat I was cruising at 80mph and towing I was rolling at 70mph.

When I first got the muffler I was a little bummed that the muffler was real quiet. It's "seasoned" now. It's got a little burble now and you can hear it under load at 2000 rpm. The engine still makes more noise at WOT than the exhaust. Now that I've done it, I'm glad. A guy at my work just put a Magnaflow on his truck and he says he loves it. I road with him for lunch the other day and I think it's annoying as all hell. It just doesn't have low rumble that I associate with performance. Oh well, differnent strokes...............

 

It will get even better with time. Mine is beginning to sound pretty wicked at idle and below 2000 rpm. It is a deep throaty burble. I can't wait to get the Thorley's on. This past weekend I made about a 300 mile run with about 600 lbs in the bed. Doing around 75-80 I got 19.2 mpg!

 

How?
I can't get past 14.3.

 

That is freakin amazing. My brothers VHO gets 16.5 max. Were you driving down a steep grade?

 

It was from San Antonio to Beaumont, Texas. Most of it was flat with some hills and overpasses. I was amazed to say the least. I was the last in our line of trucks, so I had someone to break the wind for me. A couple of times I was at wot to pass some traffic. My mileage has been consistently above 17 mpg the past few tanks.