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So I've scanned a fair amount on this thread, and I may be jumping the gun, but I still want to ask....Does 14 MPG sound appropriate for my truck?
Just bought a 2014 SCREW, 42K miles on it, 4x4, 3.5 TT, 6.5 box, Max tow, 3.73 rear, Front height +2.5", Rear height +1" , Tonneau cover on the bed. Has 18" MB Chaos wheels with 33" Duratracs (LT 275/70 R18) set to 40 PSI, which apparently are only an inch taller than the stock tire size. New air filter, fresh synthetic oil and MC filter, new plugs gapped at .028. Did the "pedal" reset. Drilled the IC.
Took a round trip of 150 miles this past weekend (98% Highway), and my on board showed 14.2 at the end of it. I haven't had the truck long enough to run a full tank, or even filled it yet to manually calculate it. Running down a flat concrete highway at 70MPH for the most part, the "instant" MPG was showing right at 14. NO WIND. Just the fam and a couple suitcases in the back end, figured about 625# total cargo. I used to have an '04 2.5" leveled Lariat, max tow, 3.73s, Tonneau cover, stock 18's and Hankook ATM's on it, and highway with the same conditions would get about 18mpg on the readout.
Is my issue pretty much the tires? They seem like they would be really heavy... Thinking of selling them off and going back to a stock P rated tire. Any ideas how much that would help? Has anyone done the same? I really do like the Duratracs, they look Sexy AF, and I hear they are great in the snow, so I might just work on my "who cares" attitude instead, but curiosity gets the best of me sometimes.... Thanks for any replies.
Your mileage calculations will be off because of the larger tires unless you have had your computer changed to compensate.
Larger tires rotate less and will show less miles travelled. Less miles travelled using the same amount of gas will show a lower than actual MPG reading.
Besel53: I had a 2011 eco with the 3.73 rear, like you have only diff. year. Don't expect better than what you are reporting. The 3.73 is the weak link as far as mpg. I traded for a 3.31 and my mileage jumped a lot, on average 6 mpg more. good luck
Your mileage calculations will be off because of the larger tires unless you have had your computer changed to compensate.
Larger tires rotate less and will show less miles travelled. Less miles travelled using the same amount of gas will show a lower than actual MPG reading.
Very true. I suppose if I want an ACTUAL MPG reading, I would need to go off of a mileage reading from GPS rather than the truck, then calculate it. I don't think that the tires being only an inch taller than stock would make a huge difference, but in the long term I can definitely see it adding up.
Besel53: I had a 2011 eco with the 3.73 rear, like you have only diff. year. Don't expect better than what you are reporting. The 3.73 is the weak link as far as mpg. I traded for a 3.31 and my mileage jumped a lot, on average 6 mpg more. good luck
Rear end ratio makes a big difference but so does the transmission top gear ratio. The more modern transmissions have more overdrive giving the effect of a lower rear end ratio.
Hi Feather
I traded on a 2018, 5.0, 3.31, 6.5 bed. Lots of things different from my 2011. But to me the biggest change was going from 3.73 to 3.31 rear. I have a friend with a 2011, like mine, only difference was he had the 3.31 rear. Much better mileage than mine 2011. Can you explain more about the top gear ration in the transmission. Where would I find that information for my truck?
Because of this forum and the discussions of mileage, I filled up with Premium before going on a ~220 mile round trip yesterday. My LOM has been adjusted within 5 percent of hand calcs.
My average mpgs jumped from 20.3 to 23.2 (previous average after same trip). The premium was 29 cents per gallon (93 vs 87) more at 3.619/gal. That's roughly 12.5 percent more per gallon. The mileage increase is about 14.2 percent, so I'm money ahead, but barely. Perhaps it will improve more when I've put premium in again (there was about ¼ tank of regular left when I filled up). So I think I will be using premium all the time now. YMMV (literally). I'll fill up again today and confirm the LOM readings with hand calcs (Fuelly) - but I think that in my case, the argument that 93 is better rings true.
Because of this forum and the discussions of mileage, I filled up with Premium before going on a ~220 mile round trip yesterday. My LOM has been adjusted within 5 percent of hand calcs.
My average mpgs jumped from 20.3 to 23.2 (previous average after same trip). The premium was 29 cents per gallon (93 vs 87) more at 3.619/gal. That's roughly 12.5 percent more per gallon. The mileage increase is about 14.2 percent, so I'm money ahead, but barely. Perhaps it will improve more when I've put premium in again (there was about ¼ tank of regular left when I filled up). So I think I will be using premium all the time now. YMMV (literally). I'll fill up again today and confirm the LOM readings with hand calcs (Fuelly) - but I think that in my case, the argument that 93 is better rings true.
Thanks for your real figures. I am just starting to use premium now in my ‘15 Lariat w/2.7. I’ve only had it for 2 months.
I explained in another thread about how I dumped my one year old generator fuel into my truck to refill with fresh. I use non-ethanol premium for storage for my generator. I ended up with about a 50/50 mix in the truck tank of regular 87 and the non-ethanol premium. What got my attention right away was the performance boost. I live in rural area with lots of mountains and the truck pulled much better on the hills.
So as as an experiment I am going to continue using premium gas now for a while and see how my mileage is. I have also adjusted my mpg readout in the truck but always hand calculate also. I don’t plan on seeing any great increase in mileage but if I can get anything close to what you are getting I will be extatic. Even if using premium cost me a little more I will continue using it as the performance has been great for me.
Hi Feather
I traded on a 2018, 5.0, 3.31, 6.5 bed. Lots of things different from my 2011. But to me the biggest change was going from 3.73 to 3.31 rear. I have a friend with a 2011, like mine, only difference was he had the 3.31 rear. Much better mileage than mine 2011. Can you explain more about the top gear ration in the transmission. Where would I find that information for my truck?
So for your old truck the ratio in top gear was 3.73 X 0.69 = 2.5737
For the new truck it is 3.31 X 0.63 = 2.0853
Quite a difference. For the new truck with a 3.73 rear the ratio would have been 3.73 X 0.63 = 2.3499 Still an improvement over the old truck in high gear ratio.
Now look how much lower the first gear on the new truck is (4.69) vs the old one (4.17).
The overall ratio for the old truck was 3.73 X 4.17 = 15.5541 for the new 3.31 X 4.69 = 15.5239
So you have almost the same pulling power in first gear as you had but a lot taller higher gear.
Last edited by Feathermerchant; Aug 22, 2018 at 12:17 AM.
