If you're looking for the funniest stuff, I suggest starting with the Steve, Don't Eat It Homage and then the travel category. You're on your own with the older posts that have yet to be categorized.

Friday, June 27, 2008

Mother Truckers

Here's another hypermiling update. (Original story and first update.)

In addition to my normal driving I did some highway driving recently. According to Google Maps, the trip was about 112 miles each way, almost all highway. During this highway trip I tried to follow big semis, generally keeping back about 2 seconds. Speeds varied from low 60's to low 70's. On the return part of the trip, on downhill sections, I put my transmission into neutral.

I just filled up. 9.86 gallons for 348 miles which is in 35 mpg range.

224 (112*2) miles was highway, leaving 348-224=124 for my regular driving. Assuming I still got about 25.3 mpg for that then I used 124/25.3=4.9 gallons for my usual driving. That leaves 9.86-4.9=4.94 gallons for the 224 mile trip.

That's 224/4.94 = 45 mpg! Are you kidding me? Can someone have their 5th grader check my math?


wolfger said...

The problem isn't your math, it's your assumption. Or at least, your *potential* problem. As soon as you guesstimate one number in an equation, the results become about as scientific as picking papers out of a hat. Maybe a bit better, assuming your guess is a good one, but still... if you got better mpg than you thought for your guess, the end result is less impressive.

talljay said...

My normal driving is pretty consistent but you are correct, if my every day driving mileage was actually higher it would lower the mileage for the trip.

I also may have overestimated my normal mileage, which would make the trip mileage estimate too low.

Either way I don't think it's off by much. My mileage before this whole thing started was consistently between 22 and 23.

If I have to make another long (for me) trip, I'll fill up before I go and again right after the trip to get a more accurate number.

I think I can hit 50!

Anonymous said...

I have been trying your hypermiling experiment. I filled up a while back and the WRX got slightly less than 24 MPG. Since then, I have been coasting into stops, turning the engine off at long red lights and following trucks on the pike.

I have about .33 of a tank left and will have to fill up again this week. I will let you know the calc.

BTW - I got 308 miles before I had to fill up last time.

talljay said...

Mess, right? :-)

Anonymous said...

yes. Sorry.

Anonymous said...

So I filled up the gas tank last night.

The reading last fill up 308 miles and 12.9 gallons. resulting in 23.87 MPG.

Last night it was 319.1 miles and 12.2 gallons resulting in 26.15 MPG

So a 9.5% improvement.

I'm not sure how much better than that I can do given the amount of city driving I do.


talljay said...

Thanks Mess. Did that include increasing your tire pressure?