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Old Wed, May 11th, 2011, 08:50 PM
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Jackpine Jackpine is online now
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Location: Among Elk, Deer and Javalinas on the Mogollon Rim in Aridzona
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Everyone who is getting "strange" gas mileage results. First, you MUST make sure your Tire Size (TS) and Gear Ratio (GR) settings are correct for the tune you are talking about. If you have not checked the PROGRAMMER DISPLAYED speed or the DASHBOARD ODOMETER READING against some known "standard", you are using figures that are totally meaningless!

IF, you have verified that the Gryphon speed and/or the dashboard odometer reading is correct, then you need to hand calculate a gas mileage figure over 3-4 tank fill ups. I'm sorry, this is the only way to cancel out the effects of winds, climbing/descending terrain, driving environment, differences in filling the tank, etc. One tank full will not do it! I have varied between 17.X and 13.X in different fill ups. My overall average, when not towing, on the highway, is 15.X. Notice those qualifications - in town, towing, it's going to be less.

And, you cannot compare a "meaningless" figure against "stock". The stock tune is a "meaningful" setting. If the tune sees a wrong figure for your TS or GR, then the "tune's" results will be totally out in left field.

And remember, if you have the TS and the GR correct, the dashboard speedo will read about 3% fast. If the dashboard speedo is reading your ACTUAL speed, your odometer is reading about 3% low, which would give you low gas mileage results!

- Jack
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2014 F150 Platinum SCrew 3.5L EcoBoost 4x4 with SCT programmer
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