[kennedyliam38]

Hi everyone. I recently calculated my real MPG compared to the car reading. The difference was a whopping 7.5%! The car read 47.30 and the real was 51.03. This means the car was quite severely UNDER. Usually it’s the opposite. Can anyone explain why this is?? Could it have anything to do with my car being remapped stage 1?

I’ve now used OBD11 to fix it by setting the percentage correction to 90%. It’s now reading correct.

 

[Braxton1980]

How could you calculate fuel mileage that accurately without knowing the quantity of fuel used.

Also pumps shutoffs vary so it's not an accurate measure of a full tank.

 

[DCM1]

What’s the equation you’re using to calculate it?