Grrr...
 

Since my car doesn't have a trip-meter, I have to write down the odo mileage and subtract...except I can't find the mileage from my last tank nor can I remember it...so now, I just put 10 gal in her and have no idea what my MPG this tank was :mad:

No reason to reply, just had to rant :D

oh snap, coyote x adapted a $10 bicycle speedometer (which has a trip AND a clock) to his motorcycle. I imagine one could adapt it to a car,
"I wedged the magnet into a hole in the brake disk"

https://www.gassavers.org/showthread.php?t=5135

instead of doing all that complicated stuff, why not go to dollar general/walmart/anywhere and buy a $0.50 book and keep it int he glovebox... write down miles, date, gallons AND any oil changes, treanny changes, any service to the car. possibly write down like things your testing (like lets say you added some aero thing)

makes it very easy to look back over the year(s) and see whats been done.

I actually had a good log that I cooked up for my last three vehicles...had miles, gallons, MPG, $/gal, cost per mile, cost per day absolute and cost per day actually driven, with a notes column for anything that might have affected MPG. But I can't find it and it was kind of a hurried spur-of-the-moment fillup. As it turns out, though, as I was looking for something completely unrelated last night, I found the receipt on which I wrote the miles...it was 128,2 miles on 10,087 gal for 12,709mpg.

I keep an erasable marker in the cars that don't have a trip. just log the odo and the gallons on the rearview.

Hmm...now that's a really good idea...

yea it is! but knowing my luck moisture would make it come off...

or could even do it on the instement cluster if its big enough...;

www.fueleconomy.gov print out a free fuel purchase record. put it in your car and every fill up before you pull away jot down the info