827 miles per tank with 315 tires & Edge EZ

[Patriot_RAM]

Now that I have your attention -- It's true. :-laf



I've closely monitored my fuel for the past week -- 4 full tanks. The first two tanks I ran 74mph average with the EZ on level 2 and the 315/70/17 BFG tires I recently installed. I have 24k miles on the truck now and it's starting to get broke in. During test four tanks of fuel, I was trying to keep my heavy foot out of the throttle. Anyhow, hand calc mileage with the first two tanks and EZ on level 2 were 18. 4 and 18. 6 mpg. Not bad!!!



I decided to turn my EZ all the way up to the secret level 5 and see how bad it got. During the first tank with the EZ on level 5, I got an amazing 18. 5!



The last tank I decided to use the "sweet spot" and ran an average of about 68 mph through the whole tank. I spent a few miles going 75, a few going 55, 15 minutes of idle time and an hour and a half of city driving. Since I was getting ready to install a fuel tank vent mod kit, I decided to run it bone dry on this tank. I got an AMAZING 827. 7 miles out of the tank and 19. 9 miles per gallon!!! I filled the tank up with 42. 34 gallons after installing the mod. So, running the tank dry I took the tank off the truck and verified that almost 100% of the fuel in the tank had been used, so that answers the "usable amount" question that many of you have had. Also, when I ran out of fuel, it was exactly 90 miles after my DTE gauge went to zero.



All of these calculations are acurate, hand calculated, and my spedo has been corrected to 601 revs per mile for the 315 tires.



Knowing these numbers almost makes me want to slow my butt down. I'm usually running 85mph and getting about 550 miles per tank. Also -- I have the 3. 73 gears and with the larger tires I run right at 1800 rpm going 68mph on that final test. On the other tests I ran 74mph and right at 2,000 rpm. My truck is an '04 (305/555) 4x4 extended cab long bed.



Anyhow, good info to have!

 

[ttreibel]

Thanks for the info that is great mileage. What level were you on during that test 5 or 2 ? It's nice to know that you have some time to fill up after the Fuel tank chimes. Does it keep chiming after you are past empty or does it do it the once? How hard was it to restart after putting some fuel back in the tank?

 

[Patriot_RAM]

On that final test where I ran it dry, it was on level 5. Two and five seem to produce the same mileage unless you push it. I wasn't towing and wasn't in any more than moderate hills like the Ozarks.



When it started to run out, it was in a bad spot headed up a hill with no shoulder at all. It started losing power. It never started spitting or sputtering but just lost more and more power until it wouldn't pull itself along and then died. I was still in a bad spot so I tried to start it. Got it started and pulled across the highway into a driveway on the other side and it died again.



After adding the three gallons of fuel I brought with me, I left the key in the "run" position for 25 seconds and turned it off. I again turned it to the "run" position for 25 seconds and then tried to start it. It cranked for four seconds and started right up. Never missed a lick between there and the gas station where I filled 'er up. These trucks just keep getting better and better!

 

[CoastyAV8R]

To hear you put in over 42 gallons into what I assume is a stock tank, makes me think DC says the fuel tank is 35 gallons because that is what is usable without the vent mod if you were to stop fueling when the pump kicked off the first time.



How did you recalibrate the speedo for the larger tires? You got some pretty darn good mileage considering the speed and the Edge box. Mine is getting better with every mile. I'm up to 17. 9 mpg driving back n' forth to work and have gained 1 mpg when pulling our toyhauler travel trailer since the truck was new which was 6200 miles ago.



How do your 315 ride and sound at 75 mph? What kind of tires did you get?

 

[Patriot_RAM]

Superlift has a truspeed recalibrator which I've heard works well. I chose to have the dealer do mine. Most dealers charge $45 - $100, but they did not charge to do mine. The 315's I have are H2 takeoff tires on H2 takeoff wheels. There is no noticable road noise above the stock tires -- I'm happy with them.

 

[BRuppel]

yeah don't buy that superlift recalibrator when you can have anyone with a DRBIII do it for your for a lot less or maybe nothing at all. i will look up the instructions that i have and post them.

 

[Summit]

i dont understand how you get 42 gallons in a 35 gallon tank?????

i thought the short boxes are 34 and the long boxes are 35.

please explain where the light is,, i cant see it?

 

[BRuppel]

alright... . found the link with instructions. tire recalibration it is in that thread and also here:



1) Have the tech plug his hand held into the OBD port and turn it on. A menu screen comes up with a bunch of info. Select YES to go to next screen.



2) On this screen select menu item 1, "DRB III Standalone" to go to next screen.



3) On this screen select menu item 1, "1998-2005" to go to next screen.



4) On this screen select menu item 1, "All" to go to next screen.



5) On this screen select menu item 5, "Antilock brakes" to go to next screen.



6) On this screen select menu item 9, "Miscellaneous" to go to next screen.



7) On this screen select menu item 2, "Set Pinion Factor" to go to next screen.



On this screen there are a several tire sizes and Other. Select menu item 8, "Other" to go to next screen.



9) On this screen there are two items, an Axle Size, and Other. Select menu item 1, "9. 25" Axle" to go to next screen.



10) You have now arrived at the point in this process where you will enter the revolutions per mile for your tire size. Select the menu box for RPM. It will indicate 400. Here is where the tech will change the revs per mile with either the up or down arrow.



11) The last step is to select "OK" and the changes will be accepted, then the hand held will display "Reprogramming Successful".

 

[Patriot_RAM]

If you run your tank just down to the empty line and fill it up until the nozzle stops, and don't put any more in, you should have about 30 gallons. If you run the truck completely out of fuel (about 7 gallons more) and then fill it up and continue to fill it until you top it off (that's about 5 more gallons), it all adds up to a hair over 42.



I think the things that helped me get the mileage up are the 315 tires combined with not towing -- that reduced my RPMs by a good 10%. That, coupled with keeping my speed under 70 left my RPMs at about 1800 which is where they need to be to get the good mileage.



I with these things had seven or eight gears in them.