[brucepick]

When I removed my power steering belt this past winter I did a different type of A/B test.

I read the gallons per hour at idle (fully warmed up) before and after removing the belt, using the MPGuino. I found somewhere just short of .02 GPH drop with the belt removed.

I did some math to extrapolate the savings when running the engine at highway speed. It came to a couple mpg in my case.

Basic concept of the calc: I estimated maybe .017 gph decrease in consumption at 670 rpm idle. This was from the mpguino. Highway speed is 4x that rpm so would need .017x 4 additional gal per hour to run the engine with ps belt.

Then from your mpg and your highway speed, you can find your gallons per one hours highway travel. Now add your additional gph to run the ps for an hour to your gallons for one hour's highway drive. Recalculate the mpg from miles/gallons and you can see the savings.