Gas mileage

Two things. (1) The 2.5 liter engine has a little higher compression and likes rpms better than the 4.0. (2) It likes air too. Does the increased mileage justify the price of the modifications? No, but it sounds cool.

Earle

Low shift points will help with the 4.0L straight-six, but I doubt it will help with the 4-banger. They like to rev, and make more torque and HP between 2500 and 3000 rpm.

I recently clocked nearly 28 mpg. in my TJL. My secrets:

1. Gentle acceleration, low shift points. Good for 4.0's, not so good for 2.5's. I often shift at 1200 rpm. around town. I don't give a damn about butt-sniffing, stoplight-racing morons. They eventually get a clue and go around me.

1. Make the lights. Cut back your speed around town 5-7 mph. and you will more easily be able to cruise through green lights. Let the Bohemian Honda types race each other! They get great fuel mileage regardless how badly they drive, so they are of no concern. Jeeps are heavy. Starting/stopping eats fuel, especially when your ride weighs nearly two tons.

2. Shift progressively. This is something that Semi drivers do routinely, and it applies here. I have a 13-sp. transmission in the Big Truck, but I don't use every available gear if I don't have to. You can skip a gear or two to save fuel and wear-n-tear if you do it gently.

1. Lower rolling resistance. I spend most of my time on pavement, so I avoid running off-road tires. I also watch tire pressure pretty closely. You can run highway tires between 32 and 34 for better fuel mileage and longer tire life. Another way to lower resistance is to limit freeway speed to 60 mph. Tuck in 100 ft. behind a Semi for even better results, but don't tailgate.

2. Use decent fuel. Cheap fuels are usually cut with alcohol which lowers fuel mileage. You don't get something for nothing. Stick with good quality fuels that avoid excessive amounts of alcohol for better performance and fuel mileage.

1. Avoid warmups. Even in very cold regions, it is not neccessary to warm an engine longer than it takes to build normal oil pressure before you drive away. Do limit your engine speed however until it warms up to at least room tempurature.

2. Use synthetic lubricants. You will see a 10 degree reduction in internal engine temps and a 2-5% increase in fuel mileage by using good quality synthetics in the drivetrain.

1. Right-hand turn routes. UPS discovered this one a long time ago. If you are consolidating errands around town, arrange them in such a way that you make all right-hand turns. This saves a lot of time and fuel.

2. Shift to neutral! If you're running an automatic transmission, shift to neutral when sitting at a long stop light. While drive is selected, the engine is constantly under load, which uses more fuel and creates a tremendous amount engine and transmission heat. Shift to neutral if you anticipate sitting more than 15 seconds for cooler temps and better fuel mileage.

1. Don't downshift when comming to a stop. Not only does this use more fuel, it cuts your clutch life in half. Use the brakes - that's what they were designed for.

2. Keep your engine in excellent tune. Do a tune-up yearly. Investigate MIL's immediately. Buy a code scanner and learn how to use it. Don't use el-cheapo filters or spark plugs - they fail quickly. Avoid gimmick add-on's and fuel additives.

1. Park in the garage at night. This keeps the night chill off the drivetrain and allows a easier start-up and quicker warm-up when started in the morning.

2. Lighten it up! If you don't use the back seat, pull and store it. If you're just plogging around town, you don't need 200-lbs. of rescue equipment in the back, so leave it in the garage.

1. Circle the city. When I drive from one end of town to the other, I don't drive straight through: it's full of stop-signs, lights and traffic. Instead, I always plot a path AROUND the city, in a clockwise fashion, of course, to take advantage of quicker right-hand turning, using lesser-traveled rural roads.

2. Hold your lane, avoid braking. Another Trucker staple. The best drivers stay in their own lane, and only change in anticipation of a turn. If you have to hit the brakes to make a turn, you're driving too fast. Every press on the brake pedal is fuel you have wasted. Slow further back from your turns enough that you can drop a gear and make the turn without having to hit the binders for maximum efficiency. Forget about the dorks on your bumper - they don't know what you know.

1. Don't run bald tires. After 50-60% of the tread is gone, rolling resistance increases dramatically and bad weather traction suffers. Spend whatever it takes for the best quality and longest-wearing tires you can get. Name-brand tires with heavier, stiffer sidewalls offer better fuel mileage and longer wear. Avoid cheap tires like the plague they are. Avoid fitting anything wider than OEM specs as well: the wider the tires, the more rolling resistance you have to overcome.

Enough for now. I don't see any reason why you can't get 30+ mpg. in a

-JD

Billyboi sucks the s*it out of his goats ass and makes biodeisel outta it.

Some excellent suggestions, I will quibble a bit with number 10. I almost always down shift and have never worn out a clutch. I agree if your trying to wring every mile you can out of your gas you don't want to down shift if you have a carburetor but on a fuel injected engine doesn't the fuel supply cut off when decelerating?

Jeff DeWitt

JD Adams wrote:

Also #5 all gasoline in the US will be E10 (10% alcohol) due to the phase out of MTbE. Coasty

JD Adams wrote: avoid excessive amounts of alcohol for better

I have to agree with that. Use too much alcohol and those darn trees make driving difficult. :-)

Yes, and thanks to the Congresscritters rushing that into effect the oil companies are having to scramble to comply, and thats part of the reason gas prices have gone up so much.

Jeff Dewitt

Coasty wrote:

Yeah, but wouldn't it be worth $6/gallon to be able to drive 160 mph on the autobahn?

The main reason those and other countries have high gas prices is because they have only minimum refinery capability and have to import their gas form many countries of which the US is the largest supplier to all of them. Coasty

Someone's tagline says that lights timed for 30 Mph are also timed for 60 and 90! I have friends who are constantly messing with their Harleys in search of more power, but they can still be smoked by any stock 650cc crotch rocket. I prefer to drive my Jeepster when not on a bike, but it's not built for fuel economy If you really want economy, find and old VW or Mercedes Diesel, but stay away from any with engine problems. My 82 Jetta returns 50 Mpg on the freeway (rarely going there) and 40 while driving hard in the mountains. I paid $400 for it and have spent far more on tires in the last 5 years than on parts. There was one on Craigslist for $500 recently nearby, but it was an oil burner. And, for Bill, I can smell it when I follow it in another vehicle, but can't see any smoke.

Well, I think a bigger reason is that they are seriously over taxed. For instance in the 2nd Quarter of last year the Germans were paying $5.54 a gallon, $1.53 of which was the actual price of the gas, the remaining $4 was tax!

The amount the UK collects in petrol tax pays for the health service. So I don't get too upset about it. One of my US friends took out a policy, got sick, got made redundant, couldn't afford to keep up the policy and then couldn't afford the new policy (having now had a medical problem) when they got a job. The new policy would have cost thousands more than I ever would have to pay in petrol tax.

Dave