For what it's worth, i've been keeping track of my mileage fairly closely and posting 10k mile updates on DTW: If interested for comparisons sake, here is the first 3 postings and the dates listed, verbatim:
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10/3/2006:
The dirty details for all those who are interested in the fuel mileage of a 2006 diesel pickup at 10k. This is mine. Pretty much an even 50/50 city highway. There was a 3000 mile round trip to St. Louis in here, so take that into consideration. Truck is a quad cab, short bed 4x4, 3. 73 rear, automatic, SLT, blah,blah,blah ... . look at my profile if you need to know more.
Miles to date: 10299 (estimate of end of current tank)
Gallons to date: 574. 762
Average fuel economy: 17. 92 miles to the gallon
Total cost of fuel: $1789. 97
Gas to date (unadjusted*): $1823. 31
Avg per gallon diesel:$3. 11
Avg per gallon 89 octane:$3. 17
(* I have also kept track of the cost of gasoline [89 octane as per the HEMI recommendation] every time I filled up. In some cases, gas was considerably more expensive, as it was over the summer. In other cases, like now, diesel is considerably more expensive. )
Fuel mileage adjustment is as follows:
Inferred MPG for a 2500 comparable to mine: 12 mpg overall
Factor-of difference between 12 and 17. 92: 1. 49
So, the gasoline used would be the gallons used times 1. 49:
Estimated gas usage:$2722. 62
Difference between estimated gas and actual diesel cost:
Wait for it ... .
$935. 56 saved in the first 112 days of ownership.
2/19/2007:
Miles to date: 20,470
Gallons to date:1196. 586
Average fuel economy: 17. 11 miles to the gallon
Total cost of fuel:3576. 47
Total cost of gas (*unadjusted):3452. 75
*This number represents what the same volume of gasoline would have cost. It does not take into account, yet, the lower fuel consumption adjustment necessary to compensate for the higher efficiency of a diesel engine*
Average per gallon diesel:2. 99
Average per gallon gas (89 octante):2. 92
Inferred MPG of a comparably equipped 2500 Ram with a gasoline motor: 12 - This is JUST an estimate. I've heard numbers as low as 10, but for now, i'm leaving this number as is. I'll make other comparisons with lower estimates at the bottom of this post.
Factor of difference between 12 and 17. 11: 1. 43
This means that I would have to use 43% more gasoline than diesel to go the same distance I have gone, which means 3452. 75 x 1. 43:
4922. 19 adusted gas usage
The difference between the fuel usage and adjusted gas usage at 20K miles is: 1345. 72 bucks
Now, the first time I did this, over the same mileage period, I saved almost double the amount of money I did this time. This can be easily explained, I believe, by a few factors.
1. The relatively static nature of diesel prices while gasoline prices have steadily crept down. Last time the average diesel price was 8 cents lower than gasolin. Now, it's 7 cents higher.
2. The winter blend that i'm sure all my stations around here are running.
3. My heavier foot.
4. There is a distinct possibilty of ULSD having SOME affect.
5. My WAY heavier foot.
Now, i've had this thing for 250 days. Considering it's saved me 1345 bucks in that time, it means i'm saving myself about 5. 40 a day in fuel. Which, at about 30 days a month is about 160 bucks. Considering the truck costs about 95 bucks more a month for the diesel, i'm still making out.
Just in case anyone was wondering. LOL
Also, in case anyone was wondering, i've decided to show how much I would've saved if my estimates on a 2500 Ram's fuel mileage were overly optimistic (which, I think they are):
at 11. 5 mpg:1559
at 11 mpg:1793
at 10. 5 mpg:2048 (I think this esimate is probably about the most accurate)
at 10 mpg:2330
That's it, i'm done!
7/10/2007:
I'm not sure if anyone finds all this terribly interesting or not, but I hit 30k miles and it's time for my fuel update. Just for informations sake.
The lift and tires went on at approximately 25030 miles ... so about 5000 miles ago.
Miles to date: 30528
Actually miles to date tire adjustment: 30918 (7% adustment)
Gallons to date: 1850. 148
Average fuel economy to 25030 miles (before tires): 16. 989
Average fuel economy from 25030 to present (after tires): 15. 855 (adjusted 7%)
Total cost of fuel to date: 5472. 47
Total cost of gas (*unadjusted): 5457. 79
*This number represents what the same volume of gasoline would have cost. It does not take into account, yet, the lower fuel consumption adjustment necessary to compensate for the higher efficiency of a diesel engine*
Average per gallon diesel overall to date: 2. 97
Average per gallon gas (89 octante)overall to date: 2. 98
Inferred MPG of a comparably equipped 2500 Ram with a gasoline motor BEFORE tires and lift: 12
Inferred MPG of a comparably equipped 2500 Ram with a gasoline motor AFTER tires and loft: 11. 18
(My mileage is approximately 93% what it was before the lift and tires. I applied this directly to my previous estimate of 12 mpg to come up with 11. 18, assuming all factors remained the same. This a strong,non-scientific, yet necessary, assumption. )
Factor of difference between 11. 18 and 15. 855: 1. 43
(notice how the factor of difference has not changed from my 20k report, as this is a necessity to overcome statistical limitations of accounting for all the differences that may have occurred. While not an ENTIRELY accurate representation, for our purposes, it's close enough. )
This means that I would have to use 43% more gasoline than diesel to go the same distance I have gone, which means $5457. 79 x 1. 43:
$7729. 95 adjusted gas usage
The difference between the actual fuel usage and adjusted estimated gas usage at 30K miles is: 2257. 48 bucks (WOW!)(At this rate, the 6000 dollar difference will start paying me back at about 79k miles, assuming all things remain constant, and not including the higher resale value of the truck. )
So in the last 10k miles of driving, i've saved over 900 bucks by driving the diesel. Wow. Just wow. Take into account that the diesel was an extra 75 bucks a payment over each of those six months, and i've still saved 450 bucks altogether.
Now, i've had this thing for 395 days. It's saved me 2257 bucks in that time. That's a savings of 5. 71 (compare to 5. 40 from previous report) a day. That's 171 dollars a month (compare to previous report of 160) in savings just for driving it. So if the diesel cost less than 171 dollars more a month than the gasser in my payments (which it's about half that), it's worth it financially.
Just in case anyone was wondering. LOL
Also, in case anyone was wondering, i've decided to show how much I would've saved if my estimates on a 2500 Ram's fuel mileage were overly optimistic (which, I think they are):
at 11 mpg: 2402
at 10. 5 mpg: 2784
at 10 mpg: 3193
at 9. 5 mpg: 3652 (If this was the case, i'd start making money back on the deal at about 50k miles)
Now, one final aside is in regards to the loss of mileage with the new tires. They are 305/70-17 - about 34 inches tall. It's a difference in height of just about 7% (6. 989% to be exact) to the stock tires. All these figures HAVE been adjusted, where noted, for the increased distance traveled beyond what the unadjusted speedometer says (The 06 speedometer is NOT adjustable up to this size, of course!). Also keep in mind, i'm running 45 psi up front and 40 psi in the back for the Kore lift, and that can, and does, affect mileage.
That being said, my mileage before the tires was a solidly arrived at 16. 989. My mileage, adjusted, after the tires, is a solid 15. 855. That's a difference of 1. 134 mpg (LESS!). Black and white folks, the numbers don't lie.
With 3. 73 gears, with all the driving I do, probably a very close 50/50 city highway, maybe ever so slightly more city, I have lost 1. 134 mpg.
God, I wish I had 4. 10's. LOL
That's it, i'm done!
Hope you enjoyed!
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That's all of them. Hope that helps a little - or maybe it just confuses the issue more! LOL
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