Theoretical Mileage Charts
 

These guys have a theoretical mileage estimator based on vehicle weight, aerodynamics, horsepower loss of trans, etc.

MPG Estimator

Based on cars more in my 'fleet' I made up some charts I thought I would post as some generalizations (some assumptions). You can see how horsepower loss to transmission, aerodynamics, and weight can effect where you will theoretically get the best gas mileage.

I didn't bother changing BSFC between the engines...

There are so many factors that could alter results, so take it with a grain of salt. But, perhaps it could be a good rough guide for theoretical speeds for gas mileage on a given platform. It also seems to show how slowing it down could make a big difference on a small car, or even a mid-large SUV.

http://i190.photobucket.com/albums/z...e/Smallcar.jpg


http://i190.photobucket.com/albums/z...sizeluxury.jpg


http://i190.photobucket.com/albums/z...tolargeSUV.jpg

I should add that these are most likely at standard atmospheric conditions (standard air density, temp), no head wind, steady state (no on/off throttle), not accounting for rich period during warm up and acceleration, etc.. So, without a lot of warm up, head wind, and some pulse and glide, you should be able to exceed numbers for your vehicle...

I started making some horsepower loss curves for my cars and was going to do figure out how to translate it to mpg, and came across that site that did all that already.

Interesting...I'll have to look at this more when I get back from dinnah.

Looks pretty accurate for my midsize. Except that I have an auto trans and so I have some steps instead of a smooth line.