CELLryuu

Hey, I haven't posted much lately but I got the garage queen out this week and went on a little road trip.

I filled up and drove 178 miles straight highway miles. got home and the mpg said 23.7. Hell yes, I thought. best i have ever gotten by 3 mpg's. pretty much 70 mph the whole way.

So, I go to fill her up, she was half way, and it was 8.7 gallons. now for those of you not doing the math.....thats 178/8.7=20.45977 mpg???? I had it on cruz pretty much the whole way.

so the cars calculations where 3.24023 mpg off. what a jipp. not that its that big of a deal considering the rest of the car but i was a little disappointed

I have found on other cars that ive had that mpg was greatly affected by the maximum mileage value aloud by the computer. my audi will show 200 mpg sometimes and my chevy truck will only go to 99 mpg. so the audi will double the mpg value when coasting as compared with the chevy.

I didnt do this test on the c63 yet but if anyone knows that could save me another time on another test one....lazy me lol.

anyway. just felt like posting that stuff today.

cheers

Jasonoff

Inaccurate results for an inaccurate test. Makes sense

I am Jeff

I find that the displayed mpg is pretty closed to accurate. I'm usually within .5 mpg of my calculations. Are you sure you completely topped off the car before you left? Different pumps have different flow rates, your initial fuel stop might not have been a complete fill up.

CELLryuu

its possible i didnt have it topped off. on the other hand, ive never even come close to 23.7 mpgs before so it may have just been a fluke?

bhamg

My best-ever trip mileage has been 20.3 mpg, averaging a very easy-on-the throttle 80 mph over 270 miles. I don't know how one could get almost 24 mpg?

togaclk55

Pickles

Don't know about the accuracy of the C63 Computer, but the only ACCURATE way, always, in whatever car I've owned, to check MPG, is to check mileage when you fill up, check it again when you fill up....then work out your economy....that method is foolproof.
I just did a 2200K trip.....overall was 24.94MPG....much of that was on deserted Aussie roads with the cruise set on 100/110kph....but that's what I got. City running wouldn't come close to that...wouldn't even bother checking it...I mean a 6.2L V8 stop/start city running....what would be the point?
Cheers, Pickles.