How accuarate is the mpg

[Jackpine]

Originally Posted by pickemuptruck13

Hey was wondering how accurate the mpg economy was on the gryphon? I am noticing a trend when i am doing 55 - 60 i am getting 16 to 17 as soon as i go over 60 it goes down to 13 is this normal for such a drastic drop Thanks!

Bill has answered this question in another forum somewhere. The problem is, the fuel flow sensor (and I just made that up - it's called something else) is not too accurate, and it can't account for some of the variables. So, the Gryphon actually gets its information from the PCM and it is, at times, getting information that really isn't quite right.

I've noticed I'm usually well within 1 mpg of what the Gryphon says (or what the info center on my dash says, since I have a King Ranch). One thing you CAN count on, if the display drops, you know your economy is suffering, so I use it more like a "trend" instrument.

I don't know that I've seen such a drastic drop as you above 60 mph, but the wind resistance force (drag) is increasing proportional to the speed squared, so, if you double your speed, you actually increase the drag by a factor of 4. However, at very low speeds, you aren't getting the best economy either. I think the "sweet spot", if there is one, is probably in the neighborhood of 50-55 mph.

Speed kills (your economy), and so will a headwind.

- Jack