I agree that shutting the engine off isn't good, and kinnda silly. People must think you're stalling at every intersection!

Plus, 40 PSI is too high. Your tires will wear out down the middle because they are overinflated for the JK. In rain, snow or off road you will have a lot less grip. The PSI for the Jeep is based not on the tires max PSI but the weight of the vehicle and how it's distributed.

I wouldn't suggest running at 40 PSI. But, just my opinion...

 

40 PSI is way to high. Most are running 28 to 33. Although I think you still have the stock tires?

If not that must be one bumpy ride!

 

Hmmm, that sounds like a challenge. Tires are going to 40 psi tomorrow and the gps on the dash! Give me a week or so and I'll let you know.

Oh, 2008 Sahara Unlimited with manual and 3.73's

 

Call getting 19mpg silly all you want it doesn't bother me.

Yes, 25mpg would be a challenge but I believe I could do it for several reasons.

1) More gears means lower rpm's. I go 55mph on the highway and the rpm's a staggering 1800. With a 6 speed
I'd probably be doing 1600 rpm or even less.

2) I've calculated the efficiency of coasting in neutral and also covering the same distance with coasting in neutral with the engine shut off, which you can do in a stick but not in an auto.

These two advantages with the stick would give me an extra 5 mpg's or so if I tried hard enough. Wish I had the stick. 25mpg is 562.5 miles per tank. The most I've ever gotten out of my auto was 520 in a tank, or 23mpg, but I was drafting and doing all the other tricks like driving on the freeway with the right tires on the white paint to reduce friction, etc.

 

Try running it at a higher RPM. When Im on the highway going 70 mph, I get 17.4 MPG, at around 1700 rpm. Move it up to 85-90 MPH, and around 2700 RPM, getting 20.1 MPG. I think the sweet spot for the motor is between 2500-3000 RPM. JMHO

Calvin

 

If you have an auto then your gearing is 3.73 (for 2008). 3.21 is only available on the 6-speed.

Since I'm still on the stock POS tires I also keep my inflation at least to spec, sometimes a couple pounds over to maximize economy. This practice will wear out tires faster, but on this set I don't care. On an expensive set of M/Ts over-inflating would likely negate fuel savings by much faster tire wear. You are right though, driving conservatively is the single biggest change that can be done to improve fuel economy. On summer blend gas w/ the top on I regularly average about 20.5 with mine.

 

Really? I have 3.73's? Are you sure??? If so then you just made my day because I was really bummed thinking I'd have to regear in order to tow anything of significance. I'll be incredibly stoked to know I have 3.73's. Where does it say that I have 3.73's?

 

Your window sticker.

 

 

There's no way you're going to get better gas mileage at 85-90 than you do going 70.
Theres a ton more resistance at those speeds, especially on teh Wrangler.