8.1 power programmer? exhaust upgrade?

[scsparts]

Has anybody tried hypertech or other brand programmer on an 8.1 with auto.
Or exhaust upgrade?
Looking for increase in fuel mileage

[rj0001]

I used the Predator tuner and Flowmaster exhaust, both worked really well until I lifted the truck and added bigger tires. Used to average 15mpg on the highway. You can't beat the sound of a big block out of a flowmaster.

[markrinker]

What mileage did you guys see from the 8.1 in 'stock' trim?

[DalesWS6]

I have an 01 2500 HD with the Allison and I have to say I am bitterly disappointed with my fuel mileage, granted I knew when I bought it that it was no Honda but with todays technology and overdrive transmissions there is no excuse for the poor mileage of the big block. I get 12.2 with no load driving 70 on the interstate and treating the gas pedal like it was a egg, around town about 9.8. Pulling a 24' enclosed car trailer at 62 with the egg still there i got 8.6 sped up to 75 and it dropped to 7.1. I can remember my parents old 74 lincoln town car with a 460 and a 3 spd auto that got 15.5 on the road and it weighed 5400 lbs. So a truck due to wind drag with a couple of more hundred pounds should at least achieve 14 in this day and time in my opinion. I have heard that you can get the computer reprogrammed and pick up a little fuel economoy, maybe i'll try it soon, anyone out there gained any mpg improvements with a computer reprogram. thanks Good thing GM has those employee discounts cause I am thinking aboutheading down to trade mine in now on a new duramax!!