Gas milage

DanielAcosta · November 14, 2013

5.3 4x4 3.43 w stock 18 wheels I was getting 18-19 and best was 21 mpg. After the 2.5 level lift and the bigger 275/60/20 tires I'm getting 14-15 . . . I think I need a better alignment from a different shop cause I lost 4-5 mpg and that seems to be unusual or high.

As someone else already said, your mileage is a little higher than you think if you haven't corrected for your tire size. According to http://www.discounttire.com/dtcs/infoTireMath.dos, your actual mileage is 32.99/31.56=4.5% higher. So yes, you have another issue there somewhere. If you install the Hypertech speedometer calibrator like I did, you will be able to correct your speedometer and odometer, which will in turn improve your shift points and switch to V4 a little more often than what you have now.

For those who requested, I will upload some photos of the mileage on my DIC tomorrow. I was actually wrong on one: right now my 400 mile average is 20.7 (I previously said 20), but that's a little high because I just got back from a highway trip. Most of the time my 400 mile average is just over 20 even. You can look at my earlier post in this thread or signature block for the specs on my truck.

Ibex · November 14, 2013

Yep i figure the speed is off by 3-4 mph at all times now and with the mpg I'm talking real numbers. I always fill up my tank and then on the next fill up take the number of miles driven and divide that by the number of gallons/amount of gas I used. I usually assume the computer is wrong to some degree.

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mzodarg · November 14, 2013

I'm averaging 16.8 in the city, best I've gotten is 17.4 over a 20 gallon span. I have 5400 miles on the truck and I'm pleased with the mileage. I'm somewhat of a lead foot and don't really care what the MPG are. My daily commute to and from work is 38 miles, speed limit average is 40 MPH.

I've yet to really get her on the highway for an extended miles so I can only report city mileage.

Mike

mcnwil · November 14, 2013

Have never posted a pic of my DIC on the web but here goes! I am mostly rural
driving and my combined seems to be averaging 19-20. The truck seems to get
its best mileage 60-65, I ran 55 on some two lanes and it actually
seemed like the instantaneous was lower. Very happy with the mileage
though.

bladz1454 · November 14, 2013

Man, I wish I get that mileage when my trucks broken in. I'm at 600 miles and averaging almost 16 mpg.

Have never posted a pic of my DIC on the web but here goes! I am mostly rural
driving and my combined seems to be averaging 19-20. The truck seems to get
its best mileage 60-65, I ran 55 on some two lanes and it actually
seemed like the instantaneous was lower. Very happy with the mileage
though.

fondupot · November 14, 2013

Have never posted a pic of my DIC on the web but here goes! I am mostly rural

driving and my combined seems to be averaging 19-20. The truck seems to get

its best mileage 60-65, I ran 55 on some two lanes and it actually

seemed like the instantaneous was lower. Very happy with the mileage

though.

Those are great numbers. You seem to have the ideal conditions for the best mileage. Not to fast, not to slow. Bingo.

Jon A · November 14, 2013

Yep i figure the speed is off by 3-4 mph at all times now and with the mpg I'm talking real numbers. I always fill up my tank and then on the next fill up take the number of miles driven and divide that by the number of gallons/amount of gas I used. I usually assume the computer is wrong to some degree.

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Yes, that'll work but you also need to correct for the miles driven--your odometer will be off just like your speedometer so you've actually driven farther than your truck thinks you have. For example, using Daniel's numbers above you'd multiply the odometer reading by about 1.05 (for more accurate numbers go to the specs of your specific tires and ratio the "revolutions per mile" spec), then take that number and divide it by how many gallons you've used.

DanielAcosta · November 14, 2013

For those who were doubting the kind of mileage I am getting with 34" tires and a small leveling kit, here are a few screenshots. These were taken a day after my trip to the Grand Canyon, so they are mostly highway but a little less because there is a day of around town driving thrown in. For a 5.3 4x4 3.42 crew with 6.5 box rated at 16/22, these numbers seem pretty good to me. You can see all the screen shots and a detailed description for each in the album.

Swazimoto · November 14, 2013

For those who were doubting the kind of mileage I am getting with 34" tires and a small leveling kit, here are a few screenshots. These were taken a day after my trip to the Grand Canyon, so they are mostly highway but a little less because there is a day of around town driving thrown in. For a 5.3 4x4 3.42 crew with 6.5 box rated at 16/22, these numbers seem pretty good to me. You can see all the screen shots and a detailed description for each in the album.

Thank you for taking the time to post those. Since you have increased the diameter of your tire you are now getting slightly less accurate results. If I did my math in the proper direction when you travel 1 mile now you are actually traveling 1.0065 miles. Your truck is giving you slightly better results... errr I think. I know a couple of things for sure.

1. Truck looks AWESOME!

2. Truck looks AWESOME!

and... i sorta hate it when people quibble about fuel economy on truck forums (says the guys who just read the entire thread). I am sure we could find a nice bicycle forum for those really worried about. Sorry... just saying.

mcnwil · November 14, 2013

For those who were doubting the kind of mileage I am getting with 34" tires and a small leveling kit, here are a few screenshots. These were taken a day after my trip to the Grand Canyon, so they are mostly highway but a little less because there is a day of around town driving thrown in. For a 5.3 4x4 3.42 crew with 6.5 box rated at 16/22, these numbers seem pretty good to me. You can see all the screen shots and a detailed description for each in the album.

That is excellent considering CC and 34" tires. Not sure you can expect any more.

DanielAcosta · November 14, 2013

Thank you for taking the time to post those. Since you have increased the diameter of your tire you are now getting slightly less accurate results. If I did my math in the proper direction when you travel 1 mile now you are actually traveling 1.0065 miles. Your truck is giving you slightly better results... errr I think. I know a couple of things for sure.

1. Truck looks AWESOME!

2. Truck looks AWESOME!

and... i sorta hate it when people quibble about fuel economy on truck forums (says the guys who just read the entire thread). I am sure we could find a nice bicycle forum for those really worried about. Sorry... just saying.

Actually, I used Hypertech to calibrate my speedometer and odometer, so my figures are right on. You are correct that my figures were low before the calibration. My main reason for adding the Hypertech was to correct the shift points and increase V4 operation.

Thanks for the compliments, so far the truck has been great.

fondupot · November 15, 2013

Actually, I used Hypertech to calibrate my speedometer and odometer, so my figures are right on. You are correct that my figures were low before the calibration. My main reason for adding the Hypertech was to correct the shift points and increase V4 operation.

Thanks for the compliments, so far the truck has been great.

So what you are saying though is your truck is not stock, You actually tweaked the computer to stay in V4 mode more often. Interesting since most people want to disable the V4 mode. Thanks for posting pics.

90% of my driving is around town with speeds up to 50 mph and a decent amount of stop and go. My mileage is around 17-18. Which is great for a big truck.

DanielAcosta · November 15, 2013

So what you are saying though is your truck is not stock, You actually tweaked the computer to stay in V4 mode more often. Interesting since most people want to disable the V4 mode. Thanks for posting pics.

90% of my driving is around town with speeds up to 50 mph and a decent amount of stop and go. My mileage is around 17-18. Which is great for a big truck.

Not stay in V4 mode more often, but as often as designed. When you run oversize tires and do not correct the speedometer, the computer does not shift up or go into V4 as often because it thinks your speed is lower than it really is. By correcting the speedometer for the oversize tires, you restore the logic to what it was designed for from the factory. So my programming, speedometer, and odometer are stock. The only thing non-stock is the oversize tires and lift. Make sense? There is a Hypertech option to change shift points, slight hp increase, etc., but I did not do that. I bought the lower priced unit that only corrects the speedometer/odometer for tire size and differential change. I'm still running the stock 3.42 btw.

bladz1454 · November 20, 2013

900 miles and averaging just shy of 13 mpg... I'm driving more and more conservatively and its doing Nada... I might start looking into tuning options.