Another mileage question
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Another mileage question
Poor milage with my F-350 4x4 SuperCrew with 34" tires.
13 hwy, 11 city, 9 towing.
I've been really trying to drive it as easy as I can (like an old lady)
I just bought the truck and I'm not sure the computer has been calibrated to the 10% larger diameter tires. I'm going to measure out a route with a second vehicle and compare distances. How much would this affect mileage?
Also, how much could the "softness" and tread design of the tire play into MPG? What about the need for a wheel alignment...how much differance does that make to MPG?
13 hwy, 11 city, 9 towing.
I've been really trying to drive it as easy as I can (like an old lady)
I just bought the truck and I'm not sure the computer has been calibrated to the 10% larger diameter tires. I'm going to measure out a route with a second vehicle and compare distances. How much would this affect mileage?
Also, how much could the "softness" and tread design of the tire play into MPG? What about the need for a wheel alignment...how much differance does that make to MPG?
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hmm 13 is crummy. when was the last time you had your fuel filters changed or fuel water seperator drained? also, what year is our truck? how many miles? the 'softness' and tread design plays no role in mpg, it's the diameter of the tire. wheel alighment doesn't matter either. air pressure does, but would doubt that is causing 13mpg. Im getting 16-17 mpg at 70mph on my 35's. fwiw. good luck.
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Originally Posted by darsey715
hmm 13 is crummy. when was the last time you had your fuel filters changed or fuel water seperator drained? also, what year is our truck? how many miles? the 'softness' and tread design plays no role in mpg, it's the diameter of the tire. wheel alighment doesn't matter either. air pressure does, but would doubt that is causing 13mpg. Im getting 16-17 mpg at 70mph on my 35's. fwiw. good luck.
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how often should a fuel filter be changed and the seperator drained?
I am getting 13 highway, 10 city and 7 towing. stock truck with 35" tires.
2005 6.0 PSD
4X4
25K miles
3.73 gears
I am getting 13 highway, 10 city and 7 towing. stock truck with 35" tires.
2005 6.0 PSD
4X4
25K miles
3.73 gears
Last edited by The Padre; Jun 5, 2007 at 11:43 AM.
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Originally Posted by Craven Amarillo
I was getting almost the exact same mileage until I hit 15k miles. Just after rolling over 15k my highway miles went to 16.4 mpg, this is using excel to do the calculations. The towing went to about 12.5 mpg.
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Originally Posted by blackhat620
Engine is starting to break in. You will see mileage gains at 10-15K, 25K, 35K and 50K. The 6.0 (as do many diesel engines) take along time to fully break-in. The other thing that will effect fuel mileage (besides the right foot) is switching from winter blend to summer blend fuel.
I just got done talking to Matt @ LIPD and after installing all upgrades I am told my MPG will go up. I hope so.
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From: Arizona
Originally Posted by The Padre
There must be something wrong with my truck then because I have not seen any mpg increase since day one. Any ideas what is wrong with the truck? Is there a time when the PSD was made that some suck over others.
I just got done talking to Matt @ LIPD and after installing all upgrades I am told my MPG will go up. I hope so.
I just got done talking to Matt @ LIPD and after installing all upgrades I am told my MPG will go up. I hope so.
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Originally Posted by blackhat620
Well when you put the larger tires on it, have you accounted for that? They are taller, heavier and wider, which will effect the mileage. Also did you recalibrate the PCM for the new tire size? Are you hand calculating mileage or using the lie-o-meter?
Last edited by The Padre; Jun 6, 2007 at 06:45 PM.
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From: Arizona
Originally Posted by The Padre
The xlt does not have the lie-o-meter and I am hand calc'ing the MPG. I understand that the 35's are all of the above but would it make that much of a difference? How do you recalibrate the PCM on a stock truck?
To calibrate the PCM on a stock truck you have two choices, take it to the dealer and they can do it or by a "Truespeed" module.
www.superlift.com/accessories/truspeed.asp
Also understand that your odometer is not accurate as well do to the tire change.
Hope this helps
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Originally Posted by blackhat620
Yep the 35's could make that much difference what size were your factory tires?
To calibrate the PCM on a stock truck you have two choices, take it to the dealer and they can do it or by a "Truespeed" module.
www.superlift.com/accessories/truspeed.asp
Also understand that your odometer is not accurate as well do to the tire change.
Hope this helps
To calibrate the PCM on a stock truck you have two choices, take it to the dealer and they can do it or by a "Truespeed" module.
www.superlift.com/accessories/truspeed.asp
Also understand that your odometer is not accurate as well do to the tire change.
Hope this helps
After searching and reading endless threads I have made me decision to what I want to do.(as performance mods go) Plus Matt @ LIPD has been a great help.
Again thanx for the info
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From: Bossier City, LA
Yes you will need the truespeed, or take it to the dealer and have them reprogram the tire rev size. The 6.0 trucks speedometer is tied into the ABS system, henceforthe the very high liability for SCT and or others to tamper with the software directly. I can't remember off the top of my head, but it seems to me most were paying the dealership around $80-90 for the recalibration.
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From: Denver, Co
It is my understanding that the dealership will not be able to compensate for 35's or larger tires. From what has been said here on FTE, the PCM has a limit of 600 tire revolutions per mile (TRPM...because I'm too lazy to keep typing it out). The stock 20" tire & rim option (Goodyear Wrangler AT/S 275/65-20) clock in at 34.1" in height, according to the manufacturer's data. They also have a TRPM of 609. Taller tires will have a lower TRPM value.
So, you could get 600 plugged into the PCM, but that will still leave a margin of error in all calculations surrounding your speedometer, odometer, and ABS. (There have been some conversations that indicate there could also be impact to transmission shift points & torque converter lock up, but I have not seen anything definitive on that.)
At any rate, something that intercepts the signals & sends modified signals to the computer--like Superlift's TruSpeed module--is going to be your best bet to correct all of this. Between that & your GPS unit, you should be able to get things back to where they should be.
So, you could get 600 plugged into the PCM, but that will still leave a margin of error in all calculations surrounding your speedometer, odometer, and ABS. (There have been some conversations that indicate there could also be impact to transmission shift points & torque converter lock up, but I have not seen anything definitive on that.)
At any rate, something that intercepts the signals & sends modified signals to the computer--like Superlift's TruSpeed module--is going to be your best bet to correct all of this. Between that & your GPS unit, you should be able to get things back to where they should be.