mileage

[superj]

some people aren;t going to think this is technical but i think it is as i am trying to do this as scientifically as possible.

i have been testing different top speeds in each tank of gas, to see the differences in gas mileage. i had always read how if you drive at xx, you will get this much better mileage but never believed it because i always had a car that got decent mileage as long as i stayed under 100mph, my bmw, so i never cared to try anything to test the stuff i had heard. well, since the jeep is more of a cruiser and still gets horrible mileage, i figured what the hell, might as well try it out.

when i say on the highway though, i don't actually have any highway driving as i get on at one exit and get off 4 miles down the road at an exit two or three down so i am not actually doing this 30 or 45 minute run on the highway that messes up lots of people's gas mileage checks.

so far, my previous tank was done at 70-72 on the highway and whatever speed the normal city roads were doing. i got 11.5 on my last tank of driving only in the city. which has been the norm for this jeep, unfortunately.

the tank prior to that was 10.6.

the tank prior to that was 11.4.

so you see my baseline, about 11mpg.

this tank, i drove at 60 on the highway. nothing above it at all. i also drive whatever hte posted limit was on the streets. if it said 40, i did 40. if it said 25, i did 25. i haven't filled up yet but i am at 221m on this tank, roughly 60 miles more then i normally get on a tank as i fill up between 160 and 170 normally.

once i fill up, i will come back and post my final numbers but why don;t you guys try it out and see what ya'll can get too

 

[LilRedYJ]

Ok I'll participate in your quasi-scientific Experiment
Last tank : well, let's round up & call it a whole 9mpg...... But all city ... Only 1short hwy. Trip ....

This tank: still in progress... But almost all highway so far... (Avg. Hwy. Speed about 55mph )

I'll post new data at next visit to Valero!

[☠]lllllll[☠] 89 YJ ...SOA +6.5...44"Trxus' I Love my dirtYJeep! [☠]lllllll[☠]

 

[superj]

sweet. thanks

 

[ralavoie_417]

I usually avg about 15 mpg. On a road trip to lake Tahoe from Los Angeles I got about 17 mpg. But due to the awesome and super proactive law enforcement of the California highway patrol on hwy 395, I set the cruise control at the posted speed limits.
I run 37 inch tires with 4:88 gear ratio, with a stage II superchip. Considering all the mods and load on my jeep, I am happy with my mileage.

 

[Jester32]

I average about 4-5. But my 4.0 l is rarely below 3000 rpm.

 

[Dawgvet06]

I get about 17 with cruise control on the highway at 65 mph. Closer to 13-14 city driving. Pretty close to what the original window sticker on my 01 TJ states it should.

 

[wareaglewild85]

Approximately 14-15 around town. Got right at 19 on a five hour interstate jaunt during the summer running right at 75 mph the whole way. It fluctuates based on moon phases, gremlins or how you hold your mouth I think!:roll:

Really, though, I didn't buy my TJ for the mileage...just sayin'!!

Peace! :shades:

 

[superj]

i realize no one buys a jeep for gas mileage but it is something we should all think about once in a while as gas prices are not going to go down and will probably continue to rise. there will become a point where driving these will become a special deal because that 11 mpg will be so outrageous to fill up that it will be cost prohibitive to use for a daily or even a weekend driver for everyone but fairly rich people. (not saying this is going to happen soon, but it will get to that point)

i would like to improve the efficiency on mine while its still practical to use a daily driver so i can lengthen the amount of time it is usable. my jeep is not an off roader and sits totally stock on light truck tires that i would barely consider an all terrain, more of a road tire. my jeep is used to run the kids to practice or take to work every once in a while so the more gas mileage i can get, the better.


i know lots of people will say "get a honda" but thats pretty damn close minded and stupid to say to someone. i hate to read that as an answer to people's questions because that is just showing that jeep people are only jeep friendly to people who don't point out anything against what they want to believe.

i am glad that everyone on here is open minded to different ways of thinking. this would be an argument on jeepforum because some people would've already made the honda comment.

 

[Gennybro]

I drove my jeep from Harrisonburg va,to gettysburg pa on interstate 81.Going 55mph,cause thats the best I could get out of this 4 banger with 33x12.5 tires.Got 19 mpg,which surprised me,but around town and the country roads,Ive been getting 14 mpg. One good reason I decided to resurrect this for those little trips around town. Never worked on one before,guess it'll be a learning experience.

 

[superj]

that is sweet. i think one of those would be a blast for little run around trips.

 

[superj]

ok, i got 12.2 mpg on this tank, 1.2 better then normal which sounds like about a 10% percent increase over not watching my speeds.

the problem is that 10 percent sounds great but in reality is only about 1 mpg more then when i drive how i want to.

that sucks.

 

[cali_92]

some people aren;t going to think this is technical but i think it is as i am trying to do this as scientifically as possible.

i have been testing different top speeds in each tank of gas, to see the differences in gas mileage. i had always read how if you drive at xx, you will get this much better mileage but never believed it because i always had a car that got decent mileage as long as i stayed under 100mph, my bmw, so i never cared to try anything to test the stuff i had heard. well, since the jeep is more of a cruiser and still gets horrible mileage, i figured what the hell, might as well try it out.

when i say on the highway though, i don't actually have any highway driving as i get on at one exit and get off 4 miles down the road at an exit two or three down so i am not actually doing this 30 or 45 minute run on the highway that messes up lots of people's gas mileage checks.

so far, my previous tank was done at 70-72 on the highway and whatever speed the normal city roads were doing. i got 11.5 on my last tank of driving only in the city. which has been the norm for this jeep, unfortunately.

the tank prior to that was 10.6.

the tank prior to that was 11.4.

so you see my baseline, about 11mpg.

this tank, i drove at 60 on the highway. nothing above it at all. i also drive whatever hte posted limit was on the streets. if it said 40, i did 40. if it said 25, i did 25. i haven't filled up yet but i am at 221m on this tank, roughly 60 miles more then i normally get on a tank as i fill up between 160 and 170 normally.

once i fill up, i will come back and post my final numbers but why don;t you guys try it out and see what ya'll can get too
__________________
1987 jeep wrangler

it sounded like you were going to compare mpgs at different highway speed or the efficiency of gas millage at different rpms. example running on the freeway at 3000 rpms going say 65 as opposed to 2500 going 55-60 somewhere in that range.

from my personal experience i only get about 13.5mpg avg in my 2.5 on 33s when cruise at around 2500rpms on the freeway doing about 62mph. going faster then that my mpgs drop to about 2.

but i was curious to see if i ran say at 3200rpms in 4th gear i would get better effeciency then say driving in 5th at 2300rpms. if any of this makes sense...

 

[flatie46]

I've got a CJ5 with the 304 V8 and a 4spd. It has 3.54 gears and 31-10.50's on it. I checked it a while back and it was getting a solid 14mpg. That was mainly running 40 to 50 mph and around town. Also that's with the engine needing some tuning and with a very worn out timing chain. Just replaced the chain and got it in really good tune. Will post the results soon, headed to the beach tonite.8)

 

[TerryMason]

It's easy to track fuel mileage with the newer TJs. You just plugin a ODBII connector of some sort. In my case I have a wireless connector paired with my Droid phone, running a program called Torque.

Instant MPG is on the left and average is on the right (it's higher than normal because I just pulled out the driveway).

 

[JohnnyO]

The Jeep is for my daughter, mpg with the 4-banger, 3 speed automatic, and as near as I can tell 4.11 gears, is too awful to speak of.

That said, I have played with different speeds in my '08 Sport Trac which has a digital mpg thingy on the dash. I routinely take a toll road between my two offices, has a few hills but not too bad, 19 miles between toll booths. I will reset the display at the first toll booth and try different speeds and see what it says at the second one.
On average:
65 mph = 20-21 mpg
70 mph = 18-19 mpg
75 mph = 17 mpg
80 mph = 15 mpg (yes I have a radar detector)

My theory is that Jeeps and trucks have more wind resistance than cars so you will lose mpg at a faster rate as you increase speed than you would in a car.

My Sport Trac isn't totally stock, I do run a Gibson cat-back exhaust, K&N filter, and 38 psi in the stock size tires. It is rated at 19 hwy so I figure when I can beat that, I'm ahead. Seen as high as 23 mpg at a steady 65 mph in Florida where it's flat.

 

[superj]

i don;t mind driving 60 on the highway, i leave early anyways because i don;t like being late (at all). but driving in town, doing the slow take offs and 35 on the street where everyone else was doing 45 - 50 got old. i guess i will keep with traffic on the streets and that one or two exits worth of highway driving will be done at 60mph.

 

[Gotta-P]

We don't take our Jeep on the highway much, most of our driving is running errands and a trip to work and back once a week, so pretty much 100% city driving and never over 50 mph. I have been averaging in the high 17's with my best being 18 mpg. of course this is with stock suspension and nearly stock tires (w/street tread) that I keep inflated to about 40 psi. I also watch how I drive and don't make jack-rabbit starts and try to anticipate traffic flow and up-coming traffic lights to maximize my mileage. My daily driver is a Toyota Prius that I average about 53 mpg city with, so a lot of the driving technique I have learned from the Prius I apply to the Jeep and it apparently has helped. A buddy at works swears he can't get better than 14 mpg from his Jeep and he has stock tires and the 4 cyl engine.

 

[superj]

mine is stock everything too. i can't get it to get more then 12 in town. on the highway (i have only taken it out of town once) it gets decent mileage.

 

[Gotta-P]

mine is stock everything too. i can't get it to get more then 12 in town. on the highway (i have only taken it out of town once) it gets decent mileage.

What pressure are you running in your tires? look on the sideway and see the max pressure listed. You can safely run that pressure, which will increase gas mileage. I run 40 PSI in mine, the sidewall rating is 45 psi, but the ride is harsh at 40, so I haven't gone any higher. If you can, try running them with 40 psi and see if it makes a difference.

 

[superj]

i usually run at 32-35psi. i have street tires on mine too