| Author |
Message |
    
Michael Villanueva (Michael)
| | Posted on Tuesday, September 17, 2002 - 09:54 pm: | 
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Ok, here are my findings. After driving the same route three times (back and forth to Zuni, 289 mile RT, mostly I40) over the past few days, and tracking the mileage via the DSII odometer, my GPS, as well as checking lengths of interstate via the trucker mile stick method, I have learned that the odometer on the DSII is not calibrated for the 265 tire size.
The odometer will read _under_ with 265s mounted on a DSII. The correction constant needed is 1.096 (SD=.0012). If you are running 265s, you multiply your mileage from the odometer by that constant and you will get your true miles traveled.
In other words, for every 100 miles you actually travel using 265s, your odometer will read about 9.6 miles under your true traveled distance.
This also means my obtained mileage since I put the 265s on has been 9.6% lower than true mileage. Therefore, my true mileage since installing the 265s dropped from 14.5 to 11.9 Now that is a site better. Instead of a 33% drop, I have about a 20% drop.
As far as Greg's suggestion to use the *S* button, I tried that. Once without and twice with on those same trips. Whereas using the S button never made any difference before in mileage, now for some odd reason with 265s it helps. My mileage went from 11.9 (corrected mileage) to 13.3 (corrected mileage) -- a 9% increase. Anyone have insight as to why using the S button would affect performance so significantly?
So I was wrong. There is an hitherto unknown benefit to running 265s. Say you lease your DSII for three years. And say in the first days of ownership, you swap the stocks for the larger 265s. Say in three years, your contract clears you for 36,000 miles. Any additional mileage will be an extra charge.
So now you are at 36,000 miles, you multiply the constant� and you have actually traveled 39,456 miles. You get 3,456 miles for free, saving you what? 500 dollars? Of course, you will have paid an extra 1200 dollars in gas for that last 13% drop in mileage by going to the larger size, but you saved 500 dollars!!!
Or if you are a regular owner, at the end of your 50,000 mile warranty, you actually are getting an extra 4,800 miles of pure Land Rover warranty coverage.
My data is accurately reported; however, whether or not I have correctly manipulated and interpreted it, well, here it is for peer review. |
Al Oliveira (Offroaddisco)
| | Posted on Tuesday, September 17, 2002 - 11:35 pm: |
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Wow... good stuff Michael. As I had suspected. 
Now... wanna try that with stock tires? I would be willing to bet money that with stock tires you might end up with figures that would put you out of your lease or warranty earlier than the actual miles driven.
But then with an acceptable 10% margin of error (indicating a higher than actual speed/distance traveled) you would get different results with different cars tested. |
Curtis N (Curtis)
| | Posted on Wednesday, September 18, 2002 - 01:49 am: |
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This is interesting. Not so much in the actual mileage differcence, but in the way it would relate to the termination of the lease.
Say you turn in that 36K miles lease with 38K of miles on the odometer. You are 2K over and and .20 per mile are billed $400 in excess mileage charges. You then tell the leasing company to go to hell because this is perfectly within an acceptable 5% margin of error due to odometer innacuracy.
Unfortunately, my sceanrio would fail. The contract most likely states that what is read on the odometer is the actual mileage...unless it has been tampered with. This could also put the lesee in hot water because it could be argued that changing the tire size would constitute tampering.
It would then be logical to state that if you lease your vehicle (and put on larger tires), make sure to turn it in with tires of the original size and avoid the whole controversy.
Curtis |
Greg Davis (Gregdavis)
| | Posted on Wednesday, September 18, 2002 - 09:50 am: |
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Michael, my only guess about the Sport mode helping is because it holds the shift points longer. When you have the 265's, you have geared your vehicle higher, meaning less RPM's than stock at the same speed. This translates into the engine not operating at it's peak power curve, causing the engine to "lug" around town. By engaging sport mode, you have now returned the engine to a power curve closer to what it was designed for, thus increasing efficiency. Just my guess. |
Paul D. Morgan (V22guy)
| | Posted on Wednesday, September 18, 2002 - 10:11 am: |
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Thanks for the good info Mike,
I started using Sport Mode about 2 days after getting the 265 MTR's. I enjoy it much better than the engine lugging off the stops at red lights.
I notice roughly a 3 mph difference when comparing my Speedo and my GPS. |
Rob Davison (Pokerob)
| | Posted on Wednesday, September 18, 2002 - 10:16 am: |
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let it be known that each truck is off buy a different factor. at least thats the conclusion i came up with.
rd |
Barry
| | Posted on Wednesday, September 18, 2002 - 06:03 pm: |
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I had a similar conversation with my LR Tech regarding full time use of "S" mode. He said something to the effect that you need to run a couple tanks of gas (400 miles?) with "S" on. That way the ECU will retain new parameters and engine performance will be optimized on "S".
I never bothered to experiment. Does that info compute with anyone else's experience?
-Barry |
Greg Davis (Gregdavis)
| | Posted on Thursday, September 19, 2002 - 09:33 am: |
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I was also told that it takes a while for the ECU to remap the parameters according to your driving technique, but since I keep mine in "Sport" all the time, I can't confirm how long it takes. |
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