Major MPG Decrease??

TiToCharles said:
4.0, 2013. Automatic.
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Dang. You were getting almost 400 miles to a tank. And now getting around 300. I have a 2012 DC 4x4 and the best I ever got was 347. And that was using 93 from Sunoco. I have a 2" lift in the front and 1 1/2 in the rear. Running 265x70x16. The only thing I can suggest is alignment( if you haven't done it already). I always run 92 or 93 due to having the S/C. I think your doing well if your getting around 300. All depends on your driving habit. Keeps track for a few tanks and see how it does. Keep us posted. Good luck.


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First thing is to calculate mileage properly. Miles driven divided by how many gallons of fuel used. Don't forget to consider the tire size change.
 
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OK Thanks for the math lesson all, and sorry to estimate. Thats what I am questioning as well. Is the decrease just due to a change from 265/65s to 265/70s, what the additional (im gonna estimate again) inch in diameter. Is my computer just off now, cause that makes the most sense as to why gas mileage has "changed." Then is there a way to reprogram the odometer/speedometer without buying a complete new Programmer?
 
let me restate some things.... Is a V6 really going to require more fuel due to a 2.5 inch lift and slightly more rotational weight, OR, as I am guessing, does a four inch increase in wheel circumference just **** up my computer that much? If this is the case why are there not more options for programmers and such, or access to recalibrating the current computer. Living in the mountains I have definitely noticed a change in shift points that is quite annoying. I am just surprised to see little solutions with computer issues, I thought this was like 2015 or something. Everyone seems so wishey washey on aftermarket computer hop-ups. I figured with modern vehicles being SOOO reliant on sensors and computers that there would be more options and discussion on adjusting the computer as the engine and vehicle are altered.
 
To be more accurate, figure out the circumference of new tires and then figure out what percentage bigger they are than stock. When you get your ODO reading add that percentage for a more accurate mileage traveled. Then divide by gallons used. I do this when I fill up. Use receipt to see how many gallons to fill up and ODO to see how many miles I got out of that tank (also add 15% for larger tires). But getting more than 300mi. out of these big V6's on a lift and larger tires is pretty good. You're ok. Your truck is operating normally. I'm now getting 16mpg avg. in this...ImageUploadedByTaco Forum1416327549.576207.jpg


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I would imagine your decrease is related to your lift not tires. With a lifted vehicle you have more air resistance causing lower mpg
 
ah, some aerodynamics discussion. So, your opinion is mostly lift related. I have never seen wind tunnel test type info on trucks. It surprises me that just a few inches can increase enough turbulence to decrease mpg that much. But, I can imagine that turbulence under a vehicle is hard to overcome. Its an interesting topic to think about. But, then the question is this. I would get a larger variance in MGP on the highway versus stop-n-go city, due to a lift, right? Trying to quantitate this factors is interesting. Bottom line is that it still doesn't make sense to me totally.......... I quess bigger tires explains a change in city driving, lift equals decrease on highway mpgs. Does a V8 get affected by these factors less? Does a super charger burn more efficiently or just more? Is there an ideal power where do-it-yourself mods; lifts, tires, added weight, added drag; are less affected? Is the ability to do 70 mph and still go crawl, affectively, just still a challenge to chase.......???? In the FUTURE.... anything is possible....... Perhaps with electric motors..... so many possibilities.
 
TiToCharles said:
ah, some aerodynamics discussion. So, your opinion is mostly lift related. I have never seen wind tunnel test type info on trucks. It surprises me that just a few inches can increase enough turbulence to decrease mpg that much. But, I can imagine that turbulence under a vehicle is hard to overcome. Its an interesting topic to think about. But, then the question is this. I would get a larger variance in MGP on the highway versus stop-n-go city, due to a lift, right? Trying to quantitate this factors is interesting. Bottom line is that it still doesn't make sense to me totally.......... I quess bigger tires explains a change in city driving, lift equals decrease on highway mpgs. Does a V8 get affected by these factors less? Does a super charger burn more efficiently or just more? Is there an ideal power where do-it-yourself mods; lifts, tires, added weight, added drag; are less affected? Is the ability to do 70 mph and still go crawl, affectively, just still a challenge to chase.......???? In the FUTURE.... anything is possible....... Perhaps with electric motors..... so many possibilities.
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What did he say? Lol.


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