Has anyone else had the problem that their miles per gallon calculations bear no resemblance to fact? I reset my calculations whenever I get a new tank of gas. Before I reset, I manually calculate my average fuel consumption and compare it to the E60's calculations. The car's calculations are typically 5-7 MPG higher than the actual. Is this a precise German calculation or is there some old WWII scientist in the engine compartment using a warped slide rule?
E60 iDrive MPG Calculation
- Thread starter e60hamguy
- Start date
For the price of the 5series, I would go to an different dealership and find a different tech that makes more than 7.50 an hour, who obviously is not to terribly concerned about the 40k+ you paid for you Bimmer. I hate lazy Techs. If is not right....than it is not right. I finally had to have my dealership completely wipe my hard drive clean and reprogram my iDrive in order for Emission faults to stop coming forth in my display. Took 5 times to the dealership and finally demanding to speak with the Head Tech to get the results I wanted. To many "self important" mechanics in my opinion.
Its a little bit more complicated than just throttle position. Engine load as well as a couple other factors come into play. But for the most part you're right.
One thing I can't find out is if engine temp (oil or coolant) is factored into the the formula. I doubt it is and this alone could be throwing off the calculation becuase we all know a warmed up engine is a more efficient engine.
My MPG guage is also off; I drive only @ 5 miles to work so my trips are short and the car never really warms up and I have a feeling that's what is throwing off my guage.
e60hamguy, are most of your trips on the short side?
One thing I can't find out is if engine temp (oil or coolant) is factored into the the formula. I doubt it is and this alone could be throwing off the calculation becuase we all know a warmed up engine is a more efficient engine.
My MPG guage is also off; I drive only @ 5 miles to work so my trips are short and the car never really warms up and I have a feeling that's what is throwing off my guage.
e60hamguy, are most of your trips on the short side?
It's not that advanced... why would that matter? Our cars have an electronic throttle position sensor (as do ALL electronic fuel injected engines.)
If I'm giving it 50% gas at 30 mph, it knows exactly how much fuel is being injected for the specific RPM's, at that speed, with the gas pressed down however far.
Say i give it 100% gas at 30mph going up hill... the temperature of anything doesn't matter... its just a simple calculation of how much throttle is given, what speed it's going, and the engine RPM's.
If I'm going down hill in 5th with it floored, it shoots down to about 15 mpg... and thats with barely any 'load' on the engine.
If I'm giving it 50% gas at 30 mph, it knows exactly how much fuel is being injected for the specific RPM's, at that speed, with the gas pressed down however far.
Say i give it 100% gas at 30mph going up hill... the temperature of anything doesn't matter... its just a simple calculation of how much throttle is given, what speed it's going, and the engine RPM's.
If I'm going down hill in 5th with it floored, it shoots down to about 15 mpg... and thats with barely any 'load' on the engine.
I own a 2004 530i Sports Package and the MPG calculations are off too. I reset the speedometer everytime I fill up the tank. I wish the BMW calculations were true, would save me a lot on gas. For such an expensive car, I would expect something so simple as a MPG calculation to work. But then again, it's the "ultimate driving machine" not "perfection", although you sure as hell pay for it.