I am guessing since it is for autos only that it is a reprogram to have it upshift earlier and hold higher gears longer (more closely emulating high MPG driving style in a manual transmission).

Speaking as someone with a vast background in automotive engineering, fuel science, and all that fun stuff the only other ways to get better MPG out of a vehicle are boost the thermodynamic efficiency of the engine (A.K.A. increasing the compression ratio of the existing engine or swapping in a different more efficient engine) or decrease the aerodynamic drag of the vehicle (decrease the aerodynamic profile or decrease the coefficient of drag by making the existing profile more "streamlined"). However, both of these ways of increasing MPG would apply equally between autos and manual vehicles.

If this is what is being suggested I would warn against pursuing this as most people get aftermarket programmers to do just the opposite with their automatics. Most people find that early upshifts and holding gears longer in the autos gets annoying and they are willing to pay for a programmer and the MPG penalty to have the better response of lower gears. But if there is another idea floating around in your head feel free to post and I will do my best to analyze it for you (as I would hope you would want some scientific opinion on whether your product would work before jumping into it)

 

Still not sure why a Jeep can't be fuel efficent stock, as I keep seeing new engines coming out saying they still got the power and the mpg.

 

It is quite fuel efficient when you consider the work being done to move it through the air. The JK's shape and weight are what keep the mpg's down.

 

Completely true.

This plus all those vehicles being talked about probably have high-revving engines to produce those power numbers and/or cost an arm and a leg more than a JK. There is a trade-off between cost (technology), fuel efficiency, low-end torque, and peak horsepower.

If you want an engine with a lot of power with good fuel economy, all of the technology that has to go into that engine costs a lot, so a JK would be in the 30 - 40K range rather than the 20 - 30K range. Could you afford and would you want to wheel a $40K vehicle? Would spending that extra money on the sticker price ever pay for itself by having the JK get 23 mpg rather than 19 mpg in stock form?

If you didn't pay for having higher MPG by having to pay for the technology, the other way you would pay for it would be power delivery. I am sure the engineers at Chrysler could have tuned the 3.8 to put out 250 horsepower and 23 mpg, but you would never want to drive it. People complain about the lack of low-end torque of the 3.8 as it is. If Chysler tuned the 3.8 to put out more power and better fuel economy at the same cost as the current 3.8, the place you would pay for it would be that you would be the low-end torque. Forget crawling or anything resembling normal fun offroading. You would constantly be using wheel spin to get over obstacles rather than low and slow.

 

Why would we want better fuel economy???? With great fuel economy, there would be no threads to read with "rocket surgeon" opinions. I'm just saying this is real entertainment

 

No fighting......

It can be done. An the problem is in the Auto, Not in the manuals. Manuals can do this but its a little harder and impractical.

I been studying the shifting of the jeep. When it shifts and how. There is not alot that can be done for that much. After taken a ride in a 90's model Camry. An that is where it hit me. Even if the Camry was driven like a heard of turtles. There is one thing that stuck out.

Any one who has driven a JK knows the sluggish nature of the sludge-matic. Well, this actually helps for a little bit. It reminds me of the Camry, in so many ways. An to that comes the next part in putting it all together. A guy a few years back on a news show. was telling how he was getting 100mpg out of a Honda stock.

The way i been testing what could be changed, is by shifting to Neutral on down hill or coasting areas. Well, This is the area in which needs to be changed. Most of you are scratching your heads. Every one else is probable thinking im gonna mess the transmission up. Try it and chime back in. I mean, its not gonna change a major amount, but will help. Every thing Helps at $3.24 per gallon here and climbing.

Here is my base line.

Jeep Specs:
2010 Unlimited
3.73 Axles 4x4
Soft Top with Power Doors
Homemade CAI
XHD Stubby Bumper
SEC8 Winch
Rubi Wheels and tires 32psi

Baseline fuel usage:

In Town Highway
11mpg 13mpg

Notes: lots of idling in traffic and short trips.

First Results:

In Town Highway
13.8mpg 15+mpg

Note: Same conditions as baseline. Highway mileage is still climbing, As I get better at shifting in and out of gear.

You do the math. Well, there is the problem. Is how it handles the overdrive. I am not coming out and telling you the fix. I wanna see who all can figure it out from here. I will revile it as soon as some one else figures it out.

 

If you are saying shifting to neutral to coast down hills will improve gas mileage, even slightly, I have to ask:
If the fuel shuts off when the wheels over-run the engine, how can shifting to neutral, and forcing the engine to still burn fuel to maintain idle, cause you to have better gas mileage?

I find I get the best mileage by managing the overdrive myself, rather than letting the computer do it.

For me, it's 18.5 in town, 23 highway (if I'm very careful. Normally 22 highway.).

 

You are very close, An on the right track. No, it does not cut the fuel, but does do something. In neutral there is only rolling mass on the tires. When your in gear, the engine is causing lots of drag and slows you down.



An you dot need hills to coast on highway. Try it, give it a fair chance.

 

I tend to look at it this way... For whatever energy, if any, may have been conserved shifting to neutral and coasting down the hill, an equal amount would have been used just getting up the hill in the first place. Am I wrong?

 

If the hill is steep enough so rolling down hill in neutral will cause an increase in speed, which is almost always the case here in Maine, keeping it in gear results in the fuel shutting off. The injector pulse width goes to zero, and at the bottom of the hill, I can feel the engine jump back to life when the injectors start spraying fuel again. So, for me, coasting down hill in neutral burns more fuel.

Going down a 3 mile grade, I have seen the average fuel economy display go to 79 miles per gallon.
I didn't try it in neutral because I would have had to brake all the way down.