Hi folks,

We have a long, holiday weekend coming up and I'd like to suggest folks consider benchmarking your highway speed MPG. The general senario:

1. Top-off at on-ramp
2. Cruise Control Speed Management
3. Top-off at Exit
4. Note temperature, wind direction and speed and other effects.

I don't mind if you use your mileage display or tank/odometer readings. But if you'll follow this approach, we can get more data points for MPG vs. MPG. Besides, a 'rest break' at the beginning and end of a leg tends to make the passengers much, much happier.

Thanks,
Bob Wilson

ps. I'll be running 65 mph with IFT (I Follow Trucks). I'll also be cutting across the mountains of western North Carolina.

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
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Should be interesting to see the results. The only tough part will be dealing with elevation changes and wind over the stretch that each driver chooses to do the benchmark. I did something like this last month, and got slightly different results in each direction: one way was 39.x and the other was 42.x or something similar, and that was with the cruise set firmly at 62mph. (Segment length ~90 miles each way.) Maybe it would be best if everybody tried to do this twice, once in each direction?

Agreed, roundtrip data would be far more meaningful.

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I always go the same speed on my trips between school and home, and my MPGs are never the same. I think weather/wind, has too big of an impact on MPG to really make any predictable estimates for MPH.

I have to agree. Wind or rain can really distort mpg on a trip.

My last tank (TCH) was 43.2mpg after 624 miles, all but about 90 miles (rough guess) was highway to and from work. I filled up with 0 miles to empty showing, using 14.4 gallons. I filled this morning at the same gas station and same pump used for the last fillup.

Mornings were mostly 65-70mph and light traffic, temp in the mid 60s. Afternoons are varied, often with 15 miles of 60-65mph and 10 miles of 0-30mph stop and go rush hour traffic. Afternoons have been hot, 90 to 103F this week. The TCH A/C works great on econo mode. I'm not sure how much A/C usage drops the mpg, but I'd guess around 2 or 3mpg.

When I was young and stupid, I used to drive my '67 Beetle cross country to college. One summer on my drive home, going through Nebraska toward Wyoming on I80, I decided to try to "draft" a semi to save gas. I followed this one truck about 20 miles. Then I passed him and exited at a rest stop. Well, the trucker chased me down! I was so scared (being a young gal) that I ran into the restroom and hid for about 10 minutes before leaving, thinking the trucker was going to attack me or something. I realized then that truckers really, really hate drafters, especially when you are right on their bumper.
Never did it again. In the prius when I follow a truck (IDT) I follow at least 5 car lengths back.

Except on some grades, I don't pass trucks either.

Fortunately, our Prius are fairly short and it looks like the far-from-truck, edge of the burble is exactly 5 Prius lengths. I'm not drafting, just letting the other traffic see that truck as the obsticle so they don't do rude things tailgating me.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.