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Discussion Starter · #1 ·
Whats the easiest way to get better mpg? I just took out my backseat yesterday to get rid of unneeded weight because i never use it and needed some room. Whats some easy ways to get better gas mileage?
 

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uuum, take the buss?

You bought a Jeep man, not a Prius...

Smaller tires (if you are running larger tires) so the engine doesn't have to work as hard (engine Load kills mileage).

Make sure your Jeep is serviced regularly.

CB antennas, Open tops, Accessories mounted outside your Jeep can all cause wind drag, a smoother surface is more aerodynamic and all those antennas and off road lights are working against you, the engine has to push all that weight, and then push the accessories through the wind, the faster you go the more drag has to be pushed through.
 

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Discussion Starter · #5 ·
Haha too bad i drive way too fast. And i should take off my cb antenna i dont use it much. And just like cheap ways to make it better
 

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Tune up!! Tune up!! Tune up!!. Like all above have said it's a JEEP and all the mods and equipment do it no good. I get about 7-8 uphill and 18-20 downhill, on the flat 15 so it is marginally better than my P/U.
 

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While weight and wind drag may have some impact on your mileage, I think the biggest impacts are the way you drive and the gas you use.

I am running a 1994 YJ with the original 4 cylinder engine / transfer case and 31x10.5" tires on 15" rims. I re-geared the differentials to 4.56 ratio. I have added things like a 4" lift, a skid plate, a Mean Green alternator and a FlowKooler water pump.

When I bought my jeep a few months ago, it was basically unmodified from when it was new. I took it to a local truck scale and it weighed 3000 pounds empty.

In preparation of taking my jeep on vacation, I tuned up my jeep using parts I purchased from O'Rielly's... wires, distributor cap, rotor, plugs, fuel filter, O2 sensor. As I was leaving on vacation, I stopped by the scales and the jeep fully loaded, including me and my brother weighed 4200 pounds. That's a LOT of weight for a 4-cylinder to be pulling. It was noticed when we were going up hills or longer grades. I would have to drop out of 5th gear into 4th, and on the 8+% grades, into 3rd.

For the most part, I was running with the top on, but the windows and the upper half of the doors removed. I drove a mix of trails, backroads and highways. Out on the highway, I tried to keep my speed around 50 mph. Running premium gas, my mileage ranged from 20 - 23 mpg. The higher mileage times were experienced when I was on trails and backroads where my peak spead was around 40 mph. All of this was while the jeep was fully loaded.

I noticed going down long, reasonably straight slopes with a steep grade, my jeep would speed up to about 45 mph, then hold that speed. To go faster, I had to apply pressure to the gas pedal. I think it is a mix of weight and drag versus gravity and those forces just seemed to balance out around 45 mph. So maybe there's something to be learned here... maybe it is more efficient to run these beasts up to this point, then afterwards, it starts requiring a lot of extra push for little gain. Sounds like a physics experiment in the makeing!

Before leaving on vacation, my jeep would get about 13-15 mpg around town. I was running regular 87 octane gasoline. When I got out of Texas, I started finding E85 gas which would be the advertised price on the street. When I pulled into the station, the 87 octane would be a mid or plus grade which was a lot more expensive. When I first encountered this, I saw that 90 octane gas was only a little more expensive than the 87 octane so I decided to try some of the good stuff.

My first tank of 90 octane fuel produced 20+ mpg. Thinking it must be some kind of fluke, I tried again and things got better. So I ran premium the rest of my trip.

I know they blend the gas differently here in the Dallas area for air pollution concerns. I have not run a couple tanks of it since I got back yet, so I don't know how much it will affect my mileage.

So is my experience typical? Probably not. Am I happy to tell folks about it? You betcha!
 

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Full tune up , new plugs , wires , cap, button, filters air and fuel.
Air pressure in the tires , with 31 " tires I can get another mpg if I run 35# , however I get a better ride at 25#. Other than that just remember its a brick on wheels , not aerodynamic designs for fuel mileage.

Take care !!
 

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Airaid intake system appears to help - 50+miles to the tank
 

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Dude, it's a jeep. Literally a block flying through the air with no aerodynamics. Keep the rpms below the two and don't drive over 60mph. I get 18mpg
 

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Discussion Starter · #12 ·
Well speed is my problem cause my hood tries to lift off when i drive on the highway haha. But i dont have all the money to do all the tune up stuff.
 

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the octane rating doesn't have anything to do with mpg. the 90 is not "the good stuff" 90 burns colder and longer, the 87 burns hotter and faster. different compression will require different octane levels so the motor will not knock. if you pay for 90 when you should run 87 your wasting your money
 

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Nate1010 said:
Well speed is my problem cause my hood tries to lift off when i drive on the highway haha. But i dont have all the money to do all the tune up stuff.
Yeah. At 70mph, you're jeep is working twice as hard as it is at say, 55. Just because it has to push that extra air out of the way. It's all about aerodynamics. Check all of your spark plugs and make sure they are cleaned up and not burnt off and the electrode worn down.
 

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steve1981 said:
the octane rating doesn't have anything to do with mpg. the 90 is not "the good stuff" 90 burns colder and longer, the 87 burns hotter and faster. different compression will require different octane levels so the motor will not knock. if you pay for 90 when you should run 87 your wasting your money
X2 I run 89 because I've got a spark knock that I've got to fix an the higher octane quiets her down. But if you're using higher octane in your engine for long periods of time, you're waiting your money(not too much, but still money) and you're speeding up the carbon build up in your engine because the fuel isn't being burned completely.
 

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Ride your bicycle or buy a car!

Seriously though, slow down, stock tires, keep your top up/on... I have found that really any mods won't pay for themselves in any reasonable time.

Personally, I am installing a 4bt in mine and should see the payoff from the increased mileage in only another 1,000,000 miles or so!
 

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octane rating vs power

The octane rating is a measure of what temperature/pressure will ignite the fuel. The higher the octane the higher the pressure/temperature must be. The maximum power will be derived where the fuel self ignites from the pressure/temperature.

This is the concept of the diesel. However, the gasoline engine is not built to withstand that kind of internal pressure. Therefore, the ignition/computer system is set up to ignite the fuel just prior to it self igniting (dieseling). That is the point of maximum power.

If a higher octane than the engine is designed to use, the the ignition will have to ignite prior to its optimum point and power will be lost that could have been available.

If a lower octane is used than the engine is designed to use, then the ignition will ignite later (delayed) in order to develop less pressure, hence less temperature, and keep the fuel from pre-igniting, which it would do under normal timing.
 

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If your Jeep is running properly, then there are several other things to look at. Aggressive tires (ex. mud terrain) will make a bigger difference than most would think. I have 2-97 ZJ's that both have 31x10.5's, and one has all terrains,(17-18 mpg) and the other had mud terrains(15 mpg). there is a clear 2-3 mpg difference going by the computer. They are both driven the same way, by the same person, and have similar mileage on them. (210,000-220,000)
The other thing that comes to mind on a Jeep is tires size. What is your tire size and gearing?
I just installed 4.88's on my 4cyl 90 YJ with 33's on it and the gas mileage is much better, and the engine isn't having to work as hard.
Hope this helps
 

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I just had a reality check today when i saw it was getting 12mpg with 32in tires but 15mpg with 29in tires. Im only sixteen and its my first vehicle and i pay insurane and everything else! Did som calculations and after paying insurane and fuel in about a year and a half if i bought something that got 22mpg i would be starting to "make money" and at a year i would break even and the calculations included the price of an old beater civic. So u can bet on all of my snow plowing $ buying me a beater! It seems like the 4 banngers have to run real hard which makes me thenk that the 6cyl would get better mpg, does it?
 
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