This could be a stupid question, but I just have to ask. In this day and age of 3 dollar a gallon gas, and no real relief insight, Im trying to think of ways to be able to drive my trooper. And after over a year of engine rebuild and a ton of body work and more, I want to drive it! But as we all know, even the 4 cylinder is a gas pig.
I donÆt off road near as much as I did in the past, so this trooper will be more a pavement pounder. That being the case, has anyone ever looked into tagging an overdrive box behind the transfer case for an added gearing to improve fuel economy? Or would this be the same as putting 44 inch tires on my trooper ?
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edit ::::

forgot, its the stock 4 cylinder with auto trany that has od

Still pretty early in the month, so we'll see... <img src="/forums/images/graemlins/wink.gif" alt="" />

Although the "Moab slow down" should be in full effect very soon.... <img src="/forums/images/graemlins/evil.gif" alt="" />

<img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" />

Yeah - I still have plenty of time to put my foot in my mouth <img src="/forums/images/graemlins/pfft.gif" alt="" />


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I've been thinking along these lines a bit myself lately, but not about adding an OD exactly...

I've got this one pretty long stretch of road that I travel twice a day, with a 45 MPH speed limit (enforced!) and I can't decide which is better, stay in 4th and let the engine run a bit closer to it's peak power range, or shift to fifth and drop the RPM . At some point I would think that you would start losing mileage the higher you gear it. But, where is that point ? How do I find it... I can see on my vacuum gauge that staying in 4th appears to be better, cuz it stays around 15" the whole time. In 5th, vacuum is usually MUCH lower.

I don't _think_ I'm hi-jacking, cuz the same principles should apply, no ?

HEY JEFF TRY THIS , SEE WHAT YOUR MAX VAC READING IS AT IDEL, WARM ENG , NOW FOR THE MAX FUEL ECONOMY KEEP THAT READING WITHIN 1 IN AT ANY GIVEN SPD OR GEAR AND WATCH YOUR MILEAGE GO UP,,EVERYONE HERE HAS WITH VERY FEW EXCEPTONS PROVED THAT GEARS ,BIG TIRES , RIDING HI IN THE SADDLE, AND PUSHING A BRICK, MPG IS GOING TO SUFFER, AND A LITTLE ENG WITH 2 OVERDRIVES??? , THAT ASIAN WARNER IN OVERDRIVE IS 30% OVER ALLREADY, PUT ANOTHER ONE BEHIND IT AND THE ENG WILL PROB GO DEAD WHEN IT SHIFTS IN THE THE 5TH GEAR, OR AT LEAST FEEL LIKE ,, ANYONE OUT THERE WILLING TO TAKE ANY BETS WITIN 90 DAYS TO 6 MONTH WE WILL SEE 80% OF THE NEW VEHILES STARTING TO COME FROM WHEREVER WITH UP SHIFT LITES AND OR WHAT WAS CALLED ECONOMY MINDERS AKA AS VACC GAUGES THEY USED TO BE STANDARD EQUIPT ON MID 60,S TIN INDIANS AND RANDIS KIND OF CARS (FORDS), MANY CHRYSLER AND GM CARS AND TRUCKS HAD AN ORANGE LIGHT ON THE FRT FENDER THAT WOULD TURN ORANGE WHEN YOU STEPPED ON A IT LITTLE BIT ..AND ALL WERE PRETTY MUCH VACC ACTIVATED OR RATHER A LOSS OF ... JERRY

Funny you mention that, Jerry. I just saw this in Automotive News
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Andreas Truckenbrodt, executive director of hybrid powertrain programs for DaimlerChrysler, is working with General Motors (who no longer owns any of Isuzu) and BMW to develop the Two-Mode hybrid transmission for rear-wheel-drive SUVs and luxury cars.

Q: Your engineers share an operation in Troy, Mich., with engineers from GM and BMW. Does it make you nervous working so closely with such fierce rivals?

We have a BMW-only area, a GM-only area and a DC-only area where we bring in all the integration for each application. I don't know how (GM's and BMW's cars) are going to work and look like, and the other way around.

Q: What has it been like collaborating with GM and BMW?

When you put a bunch of creative, experienced engineers together, it's amazing what you can achieve. We are building on a very good (transmission) already. But it can improve so much if you just add the experience, the lessons learned and the competency of those various engineers.

Q: How is the manufacturing going to be set up?

There will be some transmissions manufactured by GM. But we are talking about more than one for premium rear-wheel drive. There are some where GM is the manufacturer and some where maybe we are the manufacturer.

Q: Are you looking at diesel hybrids?

A hybrid diesel is certainly something that is an option. It's technically feasible. But the cost is the big issue, and that's what's stopping us at the moment. But from a technical perspective, you have to do some technical adaptation.

Q: Can you say which Mercedes vehicle will get the Two-Mode hybrid transmission?
Not today.

Q: GM says the Two-Mode transmission can deliver a 25 percent fuel economy gain. Do you agree?

A: Yes.

Q: Can the Two-Mode allow you to use a smaller engine for even greater fuel economy?

We would not develop something like this for just one engine. Modularity and flexibility is certainly the goal.

Q: Will the Two-Mode transmission be profitable?

Profit is a difficult animal. It depends highly on volume, and the volume isn't there yet. It's hard to make a profit if the volume is low. What matters more, frankly, is that the technology that you do have has the potential to be cost-effective.

Here's a stupid answer .... cause it doesn't answer your question at all, but;
1) change your tires to a highway tire tread - reduce resistance
2) K&N air filters / full synthetic motor oil
3) slow acceleration
4) try and keep yer RPM's around 3ish - this takes some experimenting - to find yer sweet spot
5) TRY not to exceed 55

I've expeienced up to 20% better economy depending on the vehicle AND how good I am......<;-)

Jerry,

I remember back around 1974 my Dad bought a fuel economy gauge. It had a hose and a T fitting for you to spice into a vacuum line that came off the manifold. He put it on his 72 F250 with a 360 in it. The fuel mileage was better when he drove it, but my brother and I couldnÆt keep our foot off that skinny pedal. But as long as you could keep the vacuum in the green section on the gauge, it did get a lot better fuel economy.

Now I havenÆt seen it, but a friend of mine with a Prius tells me his has a economy gauge, and if you he doesnÆt pay attention to his driving, he can get mileage as low as 22 mpg. But he has also had as much as 58 mpg. He recently went from St Louis to Northeast Florida , round trip cost him 150 dollars. Now I doubt the Prius has a vacuum gauge, but the moral of the story, if there is one here, is that driving habits can do a lot to your gas mileage, even when you have the greenest car around .

I got it, instead of an 2nd overdrive , how about big tires on the back. You remember, better gas mileage because your always going downhill! <img src="/forums/images/graemlins/lol.gif" alt="" />