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Unread 03-20-2010, 09:35 AM   #16
Mike97ZJ
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That's actually really good mileage.

2 things that are easy and free is to increase your tire pressure (I run 38 and noticed a big difference over the 28 that they were previously), and drive slower. Look at the instant econmy readout on your overhead console. There's a BIG difference in mileage between going 65 or 70, or even 65 or 60. I set my cruise on my ZJ to just under 60, I get the best mileage there. If it takes me a few more minutes to get there I'm going, so what.

You have to look very closely at any parts you buy to increase mileage, and ask yourself if it's worth it. If you spend a thousand in mods to get better economy, and get 1mpg better, how long will it take you to recoup that money in fuel savings.

And leave the cat on, removing it won't help mileage, and our air is poluted enough as it is.

And FYI, I only get about 14.5 with my I6 ZJ.

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Unread 03-20-2010, 09:38 AM   #17
EisBlade
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Quote:
Originally Posted by comptiger5000 View Post
Plan your driving better so you can coast more. Basically, try to drive like you have no brakes whenever possible (conserve momentum). Who cares if you only do 15 - 20 mph stoplight to stoplight in the city. If you know you're going to have to stop again very soon, picking up more speed than you need to coast to the next stop is just wasteful.
Nice. x2 on that. That's what I do. The less you brake the more efficiently you are driving. You never want to impede the flow of traffic (generally 15mph under the posted limit), but I tend to drive under the limit except in the city where I am a tad over for a reason I'll get to in a minute. On the highway the general marker is keeping it under 2K rpm, but better than that is keeping it as close to when gears changed last. I begin coasting and slowing down if there is a stop light ahead, and use some downhill momentum to lessen throttle push to get up the hill. In the city I remain aware of when the gears shift and, if I can, try to maintain a speed just slightly over to avoid gear kickdown. For example, in the city, if the speed limit is 45mph, then I stay just over when my Overdrive kicks in which is at 47mph. If I am going 50mph then I'm travelling more efficiently at the lowest rpm for the present gear. If the limit is 55mph, then I'm at about 53 because the further I get away from where that last gear shift was the less gas mileage I'm getting. While the majority of my driving may be spent like that (I rather enjoy the challenge, actually) that, I'm no granny either and there are plenty of times where I am fine in the left lane or go faster than normal if that's the flow of traffic. I have to admit; my method of driving isn't solely about gas mileage, but survivability. I used to have sooo many tickets on my license from previous cars and such. My BMW cornered on a dime and was quick, and I tested that theory constantly. The sportbike..well, what idiot wastes money on a sportbike to go slow? It all comes at a cost and only recently have I put all that behind me. No points on my license and low low insurance. Sadly, no bike at the moment either. But I'm saving up to buy my Street Glide cash.
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Unread 03-20-2010, 09:38 AM   #18
ratmonkey
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every once in a while open it up and get the rpm's up.

not every vehicle gets the best mileage below 2krpm. some get noticeably worse mileage when you stay out of the power band.

my mitsu doesn't even start moving below 2k. my grand likes to hang out between 2k and 3k for accelerating, i shift at about 3250 or so most of the time.
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Unread 03-20-2010, 10:20 AM   #19
bensonr
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My driving habits are pretty much what you guys have explained, that's why I get 16 and 20 mpg. I will raise the air pressure in the tires. I also like the idea of maybe driving over the lower speed limits to keep it in a higher gear. Is it normal for my Jeep to not shift into high gear until 50 mph no matter how easy I am on the throttle?

Thanks for all the advice, I can buy a lot of gas with the $ you guys saved me buy not buying all the after market stuff.

I like driving my Jeep. I drive my vehicles untill it is no longer cost effective to fix them. I've been waiting for the last two years for my 1995 Plymouth mini van to die so I could drive the Jeep all the time. The van did make it to 258K miles, then the tranny went, good vehicle.
I do own a 1997 Aspire with only 60K on it if the gas prices get too high, but I would much rather drive a Jeep.
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Unread 03-20-2010, 10:31 AM   #20
metalhead
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I used to be so gung ho about saving gas and when prices went up to 4 bucks a gallon I traded my 05 dodge dakota for a Jeep Patriot. I loved the gas mileage of the patriot but was not really happy with the vehicle plus a sunroof leak was the last straw. I sold it and bought the 2000 grand cherokee. I learned one thing, if you don't like the vehicle you drive all the great gas mileage you may get means nothing.
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Unread 03-20-2010, 11:12 AM   #21
QuadraTokn
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Also, remember that if you increase the tire pressure, you may get excessive wear on the inner part of the tread.

After you increase the pressure... draw a thick line across each tire using chalk, drive a couple houses down your street, and look where the chalk wore off. If it wears more on the inside you may want to decrease the pressure if you dont want to go through tires faster.
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Unread 03-20-2010, 02:18 PM   #22
comptiger5000
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With mom's 4.0 WJ, best gas mileage seems to come if you let it shift right about 2000 rpm on accel. In my 5.9, 2100 - 2200 rpm shifts give better mileage. Both are stock.
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Unread 03-20-2010, 03:32 PM   #23
sdowney717
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you just have to start over and get a different engine.
put in a small 4 cylinder turbo diesel
Turbo-Diesel Citroen C1, Turbo-Diesel Citroen C1 - 84 MPG Citroen Mileage Marathon, Eurotuner article, Tuners article
for example 68 MPG
I dont see why you cant get at least 30 mpg with a properly designed diesel in a jeep.

What you want is small engine for getting very good cruising fuel economy. You dont need a lot of power except for acceleration, once its rolling, the power required is minimal to keep it rolling along. So turbo it for power to get rolling, and make it real small.
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Unread 03-20-2010, 05:25 PM   #24
EisBlade
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Quote:
Originally Posted by comptiger5000 View Post
With mom's 4.0 WJ, best gas mileage seems to come if you let it shift right about 2000 rpm on accel. In my 5.9, 2100 - 2200 rpm shifts give better mileage. Both are stock.
And the silver lining to this might be; that you want to get through the shift points quickly to get into your cruising gear without excessive acceleration.
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Unread 03-20-2010, 05:58 PM   #25
Rickyb
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It all depends, in my 5.2 ZJ I get the best mileage going about 72MPH, best I've gotten on the highway is about 16-17MPG, in the city it's more like 11-13MPG.
It's a jeep , it's not made to get good MPG lol.
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Unread 03-20-2010, 06:20 PM   #26
bensonr
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I like the idea of a very small turbo diesel. It would get great fuel mileage and still be able to pull a boat.
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Unread 03-20-2010, 08:27 PM   #27
sdowney717
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They know how to make very fuel efficient engines like turbo diesel. I have seen where someone designed an engine that was 2 or 3 engines in one. Most of the time it runs on 1/2 of the engine. When it needs more power, extra cylinders start up for a power boost. Plus it was turbocharged. Somehow the crankshaft was split and it was a modular style engine.
Most of our engines are just wasting fuel pumping cylinders that are not needed for cruising speeds.
You do not need expensive lithium electric hybrid cars to get fantastic gas mileage.
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Unread 03-20-2010, 09:04 PM   #28
comptiger5000
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Rickyb - That mpg sounds about right for the speed on the highway. Try slowing down a bit. Crusing between 62-65, I can get 19 on flat highways with my 5.9. Crank it up to 75, and I'm getting 13-14.
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Unread 03-20-2010, 09:17 PM   #29
Rickyb
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Quote:
Originally Posted by comptiger5000 View Post
Rickyb - That mpg sounds about right for the speed on the highway. Try slowing down a bit. Crusing between 62-65, I can get 19 on flat highways with my 5.9. Crank it up to 75, and I'm getting 13-14.
When I go 65 for some reason the MPG goes down (at least thats what the overhead thing says, i reset it every trip over 20 miles), my jeep gets like 'optimum' mpg going about 72mph.
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Unread 03-21-2010, 12:36 AM   #30
ShootgunSchmid
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16-20MPG, is a good number for a WJ. I drive about 3,000 miles or so every 6 weeks. So drive alot, things to think on some of the things you list will help in some cases. Also what size wheel/tire combo you are running. It has to do with rolling restances. I avg right at 18-19 mpg with 3" lift and M/T's. Oh yeah i have the 4.0L and 233,xxx or so miles on it. all the main stuff is OE, save the lift and preformance goodies. Before the tire swap i was pulling 20-23 hwy. So it is possible. It all comes done to driving habbits and maintances. Remember its a Jeep, and drive what you want. I know when i came back from Iraq gas was close to $5 for 91 which is what i run in my mustang. I drive what i want and deal with the gas prices. Piss on Hybrids.
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