If it could yield about 3mpg or better I would be happy!!!!!!

 

5000 miles / 17 MPG highway = 294.1 gallons * 2.50$ gallon = 735.29$

5000 miles / 20 MPG highway = 250 gallons * 2.50$ gallon = 625$.

So yes, I would love 3 MPG and it would pay for the Diablo in roughly 15,000 miles of highway driving.

Or, if you did 5000 miles at 12 MPG and 15 MPG, with 2.50$ a gallon, the savings would be 200$.

Plus, you'd have an excuse to get the Diablo...

 

I'd be very surprised to see any increase especially a 3 mpg increase. As bad of fuel milage as these trucks get, I'd like to think Dodge has already rung out as much as possible. They already boast about the 20 mpg highway, don't you think they'd like to claim 23?

There's always those people that claim it increased their mileage but then you find out their calulating off the EVIC or fuel gauge. There's only one true way to measure it and that's starting with a full tank, drive it, fill it all the way up, and then divide the miles by the gallons used. It amazing how many people base fuel mileage off what their gauge reads.

 

I agree - 390 horsepower moving a 5400 lb truck (approx) 65 mph on the highway getting "20 mpg" is probably as good as it will get. Trucks have gotten around 20 mpg on the highway for so long, if possible they would be getting much better by now.
On the other hand my 1990 Chevy got 20 mpg on the highway with the 350 engine but only made about 220 hp. This Dodge gets the same mpg but puts out 390 hp and weighs a lot more. That is an improvement just not in the MPG argument.

 

Well with the current tune I reset my EVIC before I left on a 180 mile round trip. 15% city and the rest highway. I drove like a little old lady, not the way I usually drive and I got 18.6 mpg. MDS was on most of the time and average highway speed was about 65 mph.

Now before the tune, under the same driving conditions the best I ever saw was 19.1 mpg. This was after the MDS flash.

With the current tune I do not see how you can get an additional 3 mpg.

 

We just said "if". It would be great if we could get 3 mpg.

I understand that probably won't happen.

 

I think the only increase you might see is around town. City/burb mileage is all about low end torque. If they were to completely disable tm you MIGHT see 1mpg driving light to light.

 

I towed an 18 foot Basscat about 50 miles the other day and mine went into 5th gear every time in the tow haul mode. My truck, a short bed with 392 gears, 17' wheels, towing a light 1500+ may have something may to do with that though. Maybe with a heavier load it is possible it won't go into 5th, but mine did, but not any further. There is another overdrive after gear# 5, that it didn't go into.

 

There is only one 5th gear.

 

That's correct, but there is an overdrive after 5th but it locks when you are in tow mode. However, my point was fl09ramsport says that it won't go into 5'th while in tow mode and it does. Manually shift it and you will see it shift passed the 5th gear and change ratios