by the way my truck says im getting 19 1/2 hahaha

 

I get 22-23. 65mph highway driving at sea level 75-90 degree weather. But I dont think that gain will offset the price of all my mileage mods for a long time to come.

 

Make sure your odo is calibrated. After that if you don't like the mileage then loose the hero tires and you'll pick up some mileage.

I get 19 to 21 with 285/75 17 tires at 70+ mph.

 

I'm on 37's W/ 3.73's getting about the same mileage. Hand calculating between 13-15mpg tanks. Highway driving I can see up to 25mpg averaging on the overhead when I cruise around 65-70 but once I try to do 80 my overhead average starts to come down but I dont trust that thing in the slightest because its 6mpg off as it is.

 

My overhead is only off by about 1/2 mpg. If it reads 20, I'm getting 19.5.

Yesterday I drove home from Grand Lake, CO. About 1/3 is 2 lane black top, and up over Berthoud Pass (about 11K'). The rest is open highway, cruising at 70'ish. Except for the heavy stop and go traffic for 20 miles on I-70.

My overhead said 20.7mpg. I used the Smarty Jr to change tire size to make the speedomter very accurate. A little less than 1% off.

I have the smarty set at Economy (1), TQ0, TM4, and POD50.

The truck is otherwise completly stock: air cleaner, exhaust, tire size.

 

I used to get 20.5mpg with Smarty 4.06 on 5. Stock tires and wheels. As soon as I put revo on I was back down to 16mpg. Now I can't go back due to the latest update. Revo has way better power but mileage sucks and it smokes a lot.

 

if you haven't had your odo/spedo recalibrated for bigger meats then it's actually showing less miles than you actually drive. that's a big factor when hand calculating for mpg's.

 

I second that. Get your speedo recalibrated for the 37's, then check it. 37's vs. 32's will throw it off quite a bit.

 

OK. I live in MO and we just got back from a family vacation to Florida and I averaged 20.2 mpg (hand calc.) for the whole trip and that's rolling on 37's with a Smarty SR. on level 5. That was also running 85 for most of Florida and Georgia, Granted it went down to 19mpg in both those states. The only thing I did for this trip was change the fuel filter and oil before we left, before the fuel filter change I was averaging about 18 on the highway.

 

After nearly 5 yrs with my DS Predator, I found a tune that really makes a mpg difference. The 100 hp tune is their econo. tune and it MIGHT help by 1/2 mpg. My best and consistant mpg on that was 19.8 winter, no AC and 18.3 summer and AC always on. I've been running the stack extreme and driving very sanely and got ~22 on the last 2 tanks. Now the heat is on and I'm using AC a lot, so I will see what that does to the mpg. I never thought about using such a hot tune to get better mpg but it's working quite well. Just gotta watch the rt. foot. Craig

 

Did you check to see if your speedo was right before you changed with GPS? When I had stock tires my overhead was telling me I was getting 20-21 MPG. Not true because my speedo was reading 2 MPH faster then GPS. I just switched tires to 285/75 and my mpg dropped to 16 mpg even after I had a drb change the RPM to 614(or 38.86"dia) like Nitto recommends. That's where I made my mistake. Switched to a Smarty, did a bunch of 10 mile trips on the hwy at 80 MPH and compared truck trip meter to GPS trip meter and see how close I could get MPH to match to get my speedo correct. I now have my dia set to 33.30" and I'm getting a more realistic 18- 18.5 MPG. Moral of the story is my MPG was not as good as I thought it was before but its not as bad as I thought it was after my tire change. Side note my overhead MPG is reading 18.9 so that is even more accurate.

 

Also one other thing you can do is get on a highway and set you trip meter to a mile marker on the side of the road and drive about 30 miles and see how far you are off. Mile markers aren't exact either but its something else to measure too. So if you off after by est 300 ft at the marker after a 30 mile drive. That's pretty close when you think about. Figure you can drive 600 miles on a tank if you are only off 300ft @ 30 mile trip you trip meter would only be off 1 1/2 miles after a full tank. That's close enough for me.

 

The best mileage I ever got was 21.5 MPG . But I was only rolling 63 MPH with a light RT foot north bound 101 from Paso Robles Ca. This was by math not the overhead computer.