An amazing streamlining of a Jeep

[kach22i]

Originally Posted by TheEnemy

A friend gets 20+ in his lightly lifted Cherokee on the highway........

The best I've ever heard of (from a owner/friend) was 17 mpg, long trip all highway and kept the speed down.

Your friend must be doing something right.

[Frank Lee]

If "friends" don't keep gaslogs, I'm inclined not to believe their fe claims. "Yah, that magic x-cab Silverado (or whatever) of yours gets 25 (or whatever)... in your dreams." I think people like to pick that one favorable data point- gotten due to fill error or perfect conditions or ?- and put that out there all the time. Like my 69mpg Tempo; those numbers aren't cooked but they aren't representative of the real average either, by a long shot.

[TheEnemy]

I'll admit it is what he claimed I didn't see any proof, when I questioned him about it he said he kept his tires at 50psi. Synthetic oils, intake and exhaust work. Other than that he kept it in good tune. My CJ has worse aero, worse engine, higher rolling resistance and manages 12-15 on the freeway at about 65. (12 was with a pretty strong head wind, 15 was on a calm day.)

[NachtRitter]

So we are supposed to get something out of the 'smoke pattern' when the guy is basically standing between the fan and the smoke canister?? Hm. And as mentioned before, it really is an apples to oranges comparison... different weights, different rolling resistance, different usability. Very cool looking result, I agree, but the presentation was seriously dumbed down.

[Xist]

I cannot imagine that they did A-B-A with the Jeep, but did they even do A-B? How far did it coast before they added mass and made it more aerodynamic?

Honestly, they might as well have done a full A-B-A, do you think that they left it ecomodded?

[euromodder]

Originally Posted by sgtlethargic

I'm gonna have to think more on this one. At first I thought inertia didn't matter on level ground, but now I'm thinking, "Yeah, air drag force would work against inertia."

The more weight, the more kinetic energy in the moving body.
This energy has to be dissipated somehow.
Part of it by the air drag.
Mechanical resistance - wheel bearings etc. - and mostly the rolling resistance, which in turn is a factor of weight.

But the effect of mass on kinetic energy in a body (0.5 x mass x speed squared), is far more influential than the effect of weight on rolling resistance.

So the heavy body rolls further than a lighter one - other factors being equal.

[mikeyjd]

Sweet!