My intersting MPG experiment...

[TheRobSJ]

Last week, I had to attend a training class in fabulous Los Angeles. I chose to drive my on car instead of taking a company loaner car or even flying. Though it had been ahile since I'd made that drive by myself, it still got boring fast. So to amuse myself, I saw what kind of mileage readings I could see on my car's instant mpg display if I held the cruise at certain speeds.

Some folks already know that a modern Corvette, despite having a huge low tech V8, does really surprisingly well on open road. If I don't let cruise control do the driving and I actually try to hold the speed myself, I've managed to have the readng show a steady number in the high 30's if I hang out in the 68-73mph speed. But what about higher speeds?

So here's 85mph. Btw, it's over 100 degrees the entire time I'm on I-5 and my A/C is running the entire time. I'm sure that didn't help my numbers here.




Now what happens if we add another 10mph.



OK, pretty substantial drop there. How about a little more speed?




Well damn. It actually didn't drop back down below 22mpg until I was doing over 110mph. The rule of aerodynamic drag is the faster you go, the more horsepower you need to do so. So I'm assuming this all has to do with the gearing of the car. By going faster, yes we do need more horsepower to do so, but now the rpms of the engine are getting into the fatter part of the powerband, so the engine is actually operating more efficiently.

And in case anyone is curious, it gets 4.1-4.2mpg at speeds at absolute flat out top speed.

But for the record...especially for you LEOs or holier than thou safety nazis...none of this ever happened ktnxbye.

[c4c5specialist]

That is absolutely cool.

[aquaholic]

it actually has the most to do with how far your pushing that gas pedal down. if your going 140mph and let of the gas completely to coast it will show numbers in the 60-70mpg range. i've seen mine show over 80mpg instantaneously while coasting down a large hill doing 70 or so..

[LLC5]

I wonder how many cars can accomplish that at under 2500 rpm.