Email dealer about calibrating for my tire size
05-12-2007, 10:53 AM
#16
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After I put my 295's on I was at the dealer and complained about the mileage. The mileage was bad before the new tires as well. They did a re-flash and re-programmed for the larger tires. (No charge) They did not say anything about only going to 285's. When I go past one of the police radar trailers, my speedo is within 1/2 MPH of what the radar says.
I talked to my salesman yesterday who has 315's on his Mega, and he said the dealer computer will only change it to 285's also.
If my Quad Commander ever gets here and I can get some base line numbers for my truck then I will be getting a Smarty, and will see if there is a difference in programming for a different size tire with the Smarty.
Curious, What would happen if someone was running 37's and programmed the ECM to the smallest possible tire? They would actually be going for example 1.5 miles for every 1 mile on the odometer? Lets see 36,000 miles x 1.5 = 54,000 miles? I am sure this is illegal,
but is this how everything really works? 
DISCLAIMER: This is a hypothetical question and I would never recommend someone actually do something like this.
I talked to my salesman yesterday who has 315's on his Mega, and he said the dealer computer will only change it to 285's also.
If my Quad Commander ever gets here and I can get some base line numbers for my truck then I will be getting a Smarty, and will see if there is a difference in programming for a different size tire with the Smarty.
Curious, What would happen if someone was running 37's and programmed the ECM to the smallest possible tire? They would actually be going for example 1.5 miles for every 1 mile on the odometer? Lets see 36,000 miles x 1.5 = 54,000 miles? I am sure this is illegal,
but is this how everything really works? DISCLAIMER: This is a hypothetical question and I would never recommend someone actually do something like this.thanks!
05-12-2007, 11:08 AM
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Got it.
FYI, the re-flash did not change the mileage at all. It has steadily went up the last few tanks of fuel now that I am at 10K miles and have towed a trailer a few hundred miles.
FYI, the re-flash did not change the mileage at all. It has steadily went up the last few tanks of fuel now that I am at 10K miles and have towed a trailer a few hundred miles.
05-12-2007, 11:20 AM
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05-12-2007, 02:58 PM
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05-12-2007, 04:50 PM
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Using this information, the easiest way to calc fuel economy is take odometer miles travelled, multiply that by 1.0294 to get actual miles travelled, then divide the product by gallons of diesel used. Piece of cake.
05-12-2007, 04:55 PM
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