I installed the Predator about 2 weeks ago and put in the 65hp tune. I also recalibrated for my larger tires - 305 70/16. I was pleasantly shocked to get 19/22 mpg the first tank on the truck's computer but when I hand calculate it it comes out more like 16. Anybody with a Predator installed have any thoughts as to what I might have done wrong or why this is happening. I had been getting around 14 prior to Predator.

All power modules modify the amount of fuel injected. It is known that your DIC will be wrong for mileage with the mod.

You did not do a single thing wrong. The predator just throws off the calculations of the trucks computer it is perfectly normal.

Eric

I also have a Predator and noticed the incorrect fuel calculations right away. Let's all keep on Diablo to figure out and fix the fuel calculations. I love having correct indicated mileage. It really helps to figure out good mileage habits; optimum speed etc;
diablo says they are working on it. My Factory tune DIC is always within 1/2 gallon of being correct with top off. GM must be calculating fuel usage based upon predicted injection or some complex system. I wonder what happened to Supply flow - return flow difference calculations? Oh Well!

your mileage seems about right. Reset the tire data to factory and you'll see even lower. I do know that the Predator is pretty accurate when it comes to calibrating the speedo, however I do not know if it has the same effect on the odometer. My assumption would be yes that MPH and Odometer are linked somehow, but than again you never quite know.

With Predator on 65hp tune my DIC is recording 20.2 mpg around town and 26 mpg on the highway cruising at 75mph no trailer or significant wind. My hand calculations are about 0.4 mpg less.I expect a change when I put 4" MBRP exhaust and 285/75R16's on it.

I have never gotten over 12 mpg on any tank. I installed the predator with 40 hp tune and adjusted for 285's and have it stacked with juice run on 1. Both tanks yielded the same 13 mpg. I dont know howanyone is getting what they are claiming. I have heard when it breaks in mileage will increase, but i am at 52000. should be broke in by now LOL.

i have 70k miles on my truck and always got 15-16 city and 17-18 hwy. I ahve the predator on the 40hp tune and still around the same, maybe because of my heavy foot when tuned.

i have 285s and the speedo is changed to reflec it and almost dead on. All my calculations are hand calculated. i guess i will ahve to get a gps in order to check things clearly. i know my odometer is off according to the signs on the side of the highway showing mileage. It is about 0.05 of a mile off from the signs. so I figure it is close enough when i go by the mile marker signs. i figure it wouldn't make that much of a difference or even if the signs are a little off.

I have never gotten over 12 mpg on any tank. I installed the predator with 40 hp tune and adjusted for 285's and have it stacked with juice run on 1. Both tanks yielded the same 13 mpg. I dont know howanyone is getting what they are claiming. I have heard when it breaks in mileage will increase, but i am at 52000. should be broke in by now LOL.
Yeah, seems to be a great variance in fuel mileage. I personally had my worst tank on my second tank of fuel. I got 13. I have gotten 20 on a trip to Delaware. I usually run about 16-18 mpg (that's hand calculated and adjusted for my 285s). I get 15 in the winter with high idle times and winter blend fuel. I experienced no mileage increase when I had my Edge, but I attribute that directly to my change in driving habits from the increased power.