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KERR
Date registered: Dec 1899
Location:
Vehicle(s):
| :( bad milage
So we took our 7 month old back to kidney doctor for his check up and we took the G because of weather.. 14* out side...
80 miles each way, all interstate. Cruise set on 75 mph... going down 10.4 on the way back 10.9 while that mileage sucks get a load of this.
Last Thursday my father traded in his SL500, I took the car, trailer, and his gmc crew cab 4x4 GAS truck down to trade the car and get its replacement. The over all trip was 700 miles. The average mileage down, 9.4mpg on 1.5 tanks of gas. The computer said with our stops for fuel we averaged 78 mph. On the way back with the lighter Pontiac we averaged 10.4 mpg but he had to climb back up the "mountain" ( more like a real big long hill) out side of a Chattanooga.. once home the computer said the average mph home was 76 mph over the 38X miles.
So Bottom line, my G with larger tires and steel wheels is getting the same mileage at 75 mph as my fathers Gas powered 2500 series truck does with a 3K pound trailer and a car on it!
Edited by KERR 1/29/2007 4:53 PM
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ewalberg
Expert
Date registered: Apr 2006
Location: Past: San Francisco. Present: Germany
Vehicle(s): 2000 g500
Posts: 1887
| Re: :( bad milage
Um, Kerr, you've got a lift which makes it push more air, but more importantly your truck is giving you values that need a correction factor of about 1.08 because of your taller tires. if your car thinks you're going 75mph then you're actually closer to 81mph and 10.4mpg is actually more like 11.2mpg (and that's assuming that it's estimator is correct, mine reads low by .5mpg on average). I find mine with my tires is actually about 1.5mpg lower than actual.
11.2-11.7mpg for 80+ miles per hour doesn't sound to strange to me... especially with the knobby tires and lift. |
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KERR
Date registered: Dec 1899
Location:
Vehicle(s):
| Re: :( bad milage
good point, im still not sure how far off it is. I found a web page on line that said i should be off 5% mph at a indicated 65 mph. |
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hipine
Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
| Re: :( bad milage
Three words for you.... Gee Pee Ess :^) Any talk about fuel economy is just wasting your breath if you haven't checked your odometer against either GPS or a measured 10 mile stretch. If you use a 10 mile distance, you get a direct readout of percent error in your odometer's 10ths position. For instance: Driving down the highway, press your trip odometer reset when you pass mile marker 257, then read the trip odometer again when you pass mile marker 267 (or 247, depending) If your odo says 10.2 that means you need to SUBTRACT 2% from the indicated distance traveled to get the actual. If after driving the same distance your odo says 9.7, then you need to ADD 3% to the indicated distance to get the actual. You can apply the same correction factors to the fuel mileage your car's computer is telling you, but it's better to double check those against a few actual fill-ups at the same station with the vehicle pointed the same direction at the same pump each time. -Dave G. |
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ewalberg
Expert
Date registered: Apr 2006
Location: Past: San Francisco. Present: Germany
Vehicle(s): 2000 g500
Posts: 1887
| Re: :( bad milage
do 100 miles if you can, much better resolution than 10 miles. Yeah, theory said mine should be about 5-6% but it was 7.5% actual. |
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