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Discussion Starter #1
Not to start a new mileage thread, but I figured out the formula for 21mpg (21.8 on the DIC)...


Drive 55.


I was on a stretch of road for about 300 miles round trip along the north shore of Lake Superior over the weekend. I took it easy and never went above 60. The road winds a lot and is a little hilly (by Minnesota standards), but I guess it evens out when going both ways. The good news is that after only 2000 miles on the truck I can already see the improvements in mileage. Heck, at this rate, I will be at 50mpg by the end of summer



On a side note, my DIC has consistantly been reading about .5 to 1 mpg better than actual.Edited by: sammy
 

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sammy said:
I figured out the formula for 21mpg (21.8 on the DIC)...


Drive 55.

Wouldn't that take all the fun out of driving?



I'm just bein' a smart ass.


I'll be happy with a consistent 15 mpg.





Gar
 

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Hell I drive 70+ all the time and the worst I have seen has been 16.5 and the best was on cruise about 200+ miles non stop and I was getting close to 18 mpg. At least that is what the DIC said. Managed to get over 450 out of that tank. So not bad.
 

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As the song says "I can't drive fifty five"!
 

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Yep, 55 will get ya 20+. Just can't drive that slow anymore, only seems like few years ago and the whole nation was 55 stay alive, now anything under 80 gets you run over. On a side note, just did a 700 mile round trip at an average of 67mph and got 16.5mpg with a 600lb 4 wheeler in the bed--2000 miles on the truck so far!
 

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I agree with the DIC info. Mine is off about the same. I can get those number driving unloaded at 65mph. In the flat rice lands of katy, Texas
 

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Sammy
I see you have 265's, how did you compensate for the added diameter of the tire?
 

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Discussion Starter #8
Race,


I had the dealer reprogram the computer with the Tech II so everything (speed & distance) is right on when checked against my GPS.
 

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Discussion Starter #10
The road that I referenced is a single lane with 55mph, so staying within the limit was not too much of a stretch



I anticipate that I80 across Nebraska at 80mph into a 30mph west wind will be a different story (that is why it is called "I80", right?).
 

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I drove 200 miles the other day and about half was driving 65 and the other half was 70 on the Interstate. And both were a little hilly. I had the 120 hp Attitude in and the computer said 23mpg and I check it and was really 21.
 

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sammy said:
Race,


I had the dealer reprogram the computer with the Tech II so everything (speed & distance) is right on when checked against my GPS.




Really? This is interesting. Last I heard, the Tech II will only reprogram the ABS for differences in tire size. It won't do anything for speedo/odo correction.


Dmaxallitech, is this something new in the '04s?
 

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My DIC consistantly reads .5 to 1.0 MPG too low, but it hasn't been reprogrammed for my 265 tires. I use my GPS to tell me how many miles I've actually driven. If I'm on a two lane road with a 55 MPH limit, I always get 20+ MPG according to the DIC, but as soon as I hit an interstate & 70+ MPH, my MPG drops to around 17-18 MPG, (depending on wind direction & speed) according to the DIC.
BTW, my truck is just over 2 months old with 14,006 miles & 336 hours. Love the truck.
 

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You think the 265's change the MPG that much? I added them with about 900 miles on my truck and was getting about 16.5 now with them I am at the 15.5 range. I was thinking that I just was doing more true stop and go and that was the diff. I did not think the tire size would impact that much. I see the 1 or 2 mph at 60 diff but the .5 to 1 mpg diff surprises me.
 

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I changed over to 265s with about the same mileage as you, & it was too early to tell how it affected my fuel mileage. I would THINK that it helps slightly. I was just trying to point out that if you change to a larger tire size, the DIC will show lower MPG, but your actual MPG won't neccessarily be lower.
My odometer is off 4% now with the 265s. Take 18 MPG, for example. 4% of that is 0.72, which would lower your indicated MPG on the DIC from 18 to 17.28, since it thinks you're traveling fewer miles on the same amount of fuel.
Hope I'm making some sense here.
 

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Discussion Starter #17
The dealer should have no problem reprogramming for 265's. I think the reprogramming problem comes into play when going to larger tires like a 285+. Besides, the new 3500's are available with 265's from the factory.
 

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The tech II, based on my memory, does not recalibrate the speedo, but only the ABS. I had mine adjusted to 265's and the speedo is still off. The new SRW 3500's have the tire size programmed into the computer allready since that is the only tire size they come with.
 

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Discussion Starter #19
After programming with the Tech II, my speedo is "dead on" when compared against my GPS.
 

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bartman said:
The tech II, based on my memory, does not recalibrate the speedo, but only the ABS. I had mine adjusted to 265's and the speedo is still off. The new SRW 3500's have the tire size programmed into the computer allready since that is the only tire size they come with.

I don't think there is anything to reprogram as far as ABS. Those sensors don't care about actual speed, just when the fronts are going noticeably slower or faster than the rears under braking.
 
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