Originally Posted by Rubicondon53
my Rubi " averages " 15 mpg, with medium grade gas. .
Your Rubicon would get the same mpg whether you run 87, 89, 91, or 93 octane. Octane has ZERO to do with your mpg. In fact, running a higher octane than the engine was designed to run can actually cause deposits to be left behind and the engine not perform as well and conceivably not even get as good of mpg as it could with the lower octane fuel.
How can that be? Octane's sole purpose is to make the gasoline harder to ignite and slower to burn. Octane is only added to gasoline to help keep it from igniting prematurely in high compression engines, which is why high performance (aka high compression) engines require higher octane levels.
Octane does not add power and it certainly has no ability to improve mpg. Higher octane fuesl can actually conceivably cause both to be worsened if the octane amount is higher than the engine was designed for.
Run 87 octane, your wallet and your engine will thank you... and your mpg will not decrease. Not to mention a gallon of high octane gasoline contain no additional energy content or cleaning additives than a gallon of regular grade gasoline does.
Originally Posted by JAYH.TJ
my actual milage was 200 miles until the reserve light came on then i filled it up and got 60 liters in the tank and it was brimmed and now ive done 110 miles and its nearly on the half . so i guess when it was empty it must of had about 4-5 gallons left in the tank.
In summary, pay NO attention to when your low-fue; light comes on and don't even think about using it as any part of figuring out your MPG. The low fuel light is notoriously inaccurate and when
it comes on will even change as the the fuel gauge sender ages.
The ONLY way to accurately/correctly determine your true mpg is to 1) Note the exact mileage when you fill up. 2) When you next fill up, divide the exact number of miles driven since you last filled up by the exact number of gallons it took to to refill the tank back to full. That is the onl
y accurate way of determining your mpg.
Neither the inaccurate fuel gauge position nor the inaccurate low fuel light are ever a part of the mpg calculation.