|05-28-2011 02:36 PM|
re: city driving has tremendous effects on my mileage.
Whether I just drive 'to' the city with a few errands, little rush hour, no stop & go, etc, I can expect my over all average of 22.4 (over 5000 miles all combined) to drop to sub 18. If I'm doing more driving IN the city under heavier traffic, my absolute worst has been around 16.3 IIRC (posted elsewhere). But that was for the whole fill-up to fill-up, and included all day city stuff. Bleh.
re: HP demands related to MPH.
There's a wonderful youtube clip on some of the engineering of the 1001 HP-Bugatti Veyron which reports they only need about (IF I have these numbers right)150hp to get up to 100 mph. Then to get to 200 mph then need another 250 hp. Then to get to ~300 mph they need another 700 hp, despite the slicked aerodynamics they can slick up their little road burner. Not only is there "resistance" via air-friction, there is "drag" and "lift" factors which also consume HP and fuel.
Here's one clip: http://www.youtube.com/watch?v=LO0PgyPWE3o
|05-28-2011 01:18 PM|
If you've got 6K miles onit, it won't change any more--
I have an auto/w very low diff gears and I avg 13/14 around town, 12/13 off-road, but-
I can avg 18+ on the freeway !!
|05-28-2011 12:58 PM|
|fireirsh29||Have a stock2010 4 dr JK unlimited. Mainly do city driving. With a hardtop, tire pressure good, I usually run sub 14 mpg. Waiting to break her in (6000 mi.) Never seen it past 16. Hope it changes when it breaks in.|
|05-25-2011 09:33 AM|
|El Gringo||Yes, I'm not really expecting that much of a drop. Anything will beat my Bronco that got 8 city, 11 hwy.|
|05-25-2011 09:21 AM|
Heh Heh, OK, thanx, but
|05-25-2011 09:15 AM|
New heavier bumper, 2.5" lift, talking to a guy from CL about some rubi take-off tires.
I think I will be pleased.
|05-25-2011 09:03 AM|
|05-25-2011 08:54 AM|
Why are you getting on to people on several threads about their fuel economy? They are just sharing their experience.
How shitty is your mileage that the only way you can feel good is to bring others down?
I enjoy my 'good' fuel economy for now, because in about a week it is going to take a serious hit.
Live and let live
|05-25-2011 07:38 AM|
|05-24-2011 11:55 PM|
|4 Jeep Family||All stock 2011 4 door Sahara KJ 17.5 city 22.5 HWY.|
|05-24-2011 11:38 PM|
|weakkneewillie||Im at about 18.5 after 6 tanks mostly highway all stock....Ill take it!!!|
|05-24-2011 09:17 PM|
Why must my PCM lie to me?
I laughed when I saw this. Then I hand checked it. 23.7 MPG!!! Amazing what actually driving with a tailwind (30mph) will do instead of driving into it. This is even at 70-80 MPH for 100+ Mi.
|05-16-2011 07:52 PM|
|05-15-2011 04:52 PM|
Last weekend I drove 100 km touring neighbourhoods at 50 to 60 km/h (30 to 37 mph) the whole time and got 12.4 L/100 km average (19 mpg). Stock 2011 Rubicon, family onboard. That's pretty much normal logging road travel speeds, so that makes me happy.
|05-13-2011 02:27 PM|
Heh Heh, sorry and this'll really frost ya
30 mile run at 60 mph--5.38 gears/auto/O/D--
Of course it's not written in stone, but I did a "MATH" check when it read 18.2 mpg and the actual (this week) was 17.53 mpg--
You need Dealer action !!
|05-13-2011 01:26 PM|
#1. Do not freak out about mileage until you are sure your speedometer is accurate, the easiest way to check this is with a GPS unit. If your off by only one or two mph that will significantly effect mpg. It is not uncommon for stock units to be off by 2-3 mph. Throw on larger than stock tires and it gets worse from there.
#2. Gas quality varies..In my part of the country, the midwest, they use winter and summer gas blends, I see a around a 3 mpg drop on the summer blend, or any blend with ethanol.
#3. An aggressive tread compound tire of the exact same diameter will drop mileage....its all about rolling resistance. High MPG tires are very hard compounds with light tread. A tire always gets its best mpg when it is wore out.
#4. Double check that a mouse or bird has not built himself a nest in your air intake tube, this is very common. Remove the entire assembly and look through it to be sure.
#5. There are three main things I see wrong with your situation.
#1, these Jeeps take around 10k miles to be broken in and obtain peak fuel mileage, JP Magazine did a story on in when the editor bought a new 07, power and fuel mileage were horrible for the first few thousand miles, to the point he talked to Jeep engineers about it.
#2. City driving, I spent 10 years as a police officer and we would get around 9 -10 mpg in our crown vics while patrolling around town. If we went on a prisoner pick up that was hunderds of miles away, it was nothing to see 20+ mpg, more than double, so it is not unreasonable to get that kind of mileage in the city.
#3. You are driving way too fast to obtain peak mileage in a vehicle that has no aerodynamics to it. I have been driving Jeeps for almost 20 years now, and they do not do well much over 60 mph....the power to propel a vehicle through the wind rises exponentially with mph. Awhile back guys were trying to get some sport bikes over the 200mph level. Stock at around 150 hp they would do 170 mph....as they raised the hp levels, the speed only slowly crept up...to the point they were pushing well over 250hp with turbos to try to get over 200mph...and they basically said that once you get over a certain speed, it takes more and more hp to increase a single mph due to wind resistance. My point is, while an increase from 60mph to 75 mph may only be 10% or less, the increase in power and fuel burned is probably closer to 20% more.
#6. These Jeeps are underpowered. How many of you have heard that a 4cyl TJ gets worse mileage than a 6cyl TJ? Why?, because the 4cyl has to work that much harder to move the Jeep around, even though if they were both removed from the vehicles and ran on an engine stand, the 4cyl would use less fuel per hour than the 6cyl. You need to tailor your driving to suit the vehicle. No full throttle starts, try to gain speed more slowly and not use all of the vehicles available power all of the time. This relates to the gearing issues guys were talking about earlier...take a 10 spd bicycle for example...lets say it takes you 100 calories to travel 1 mile at a certain gear setting, if you alter that setting to make your workload easier, you can travel further on less calories burned because you are exerting less energy to propel yourself. Now there is a time penalty with this, as nothing is free when it comes to energy. When you gear down, you slow down, so if you attempt to cover that mile in the same amount of time as before, you may burn more energy because your a working faster even though you are not exerting as much pedal pressure.
#7. While I dont know how sophisticated the JK system is, I know a lot of newer vehicles computer also learn your driving style and sets parameters based upon that, so it will take some time for it to relearn after you alter your driving style. So you really cannot judge until you have driven some miles being easy on it. I.E. if you spend 200 miles driving like a top fuel dragster pilot, then drive 5 miles normal, I dont think you will see the same results as if you had driven the last 200 miles like a grandma.
#8. If fuel mileage, wind noise, leaks, creaks, squeaks, shimmys, or noises bother you too badly, then you will be much much happier with a Honda or Toyota. I have sold a lot of family members Jeeps in my life, and the ones that have gotten out of something like an Acura or Honda and into a Jeep have always been unhappy. The ones that traded in a old beater pick up truck have always been thrilled. If you don't spend at least 75% of the time (weather permitting) with the top and doors off, you will hate the Jeep. I know people who never take the top off and hate their Jeeps.....they say..."One good day in Jeep with the top off, makes up for all of the rest of the days with the top on." So don't set your expectations too high, understand these things are essentially pieces of junk that leak, squeak, rattle, and creak......
|05-10-2011 11:07 PM|
|themoneypit||Someone in another thread stated they found their tire pressure was at 20 instead of 32 or so and he had a similar mpg drop to yours, just a thought.|
|05-10-2011 10:59 PM|
Its terrible that the leaders of our country don't protect our American dream. Instead of just enjoying our Jeeps we have to worry about mpg's... its ridiculous. Although 11 and 13 sound terribly low man
|05-10-2011 07:35 AM|
|05-10-2011 05:05 AM|
|Lisa97||my 97, all stock (excepting I changed to 33's from stock 32's) averages around 21 consistently city/county (I'm rural and don't do much inner city driving). not much better on the interstate averages about 24mpg @ 65mph.|
|05-03-2011 09:56 AM|
|vze2372e||35's, 6spd, 5.13gears - 11.5-12.2 consistently around town, 15.6-15.8 highway at 65, 2850 rpm, cruise control, hills of Worcester. On flat ground, highway I just break 16 - my rig has been corrected with the ProCAL Module|
|05-03-2011 08:59 AM|
My read out is close, but never accurate, or consistent.
I always fill it up til I can see gas sitting in the neck, so I know its always filled to the same amount. My meter said earlier 16.4, manual was 19.8. The other day it was 19.2 and 17.8, respectively. Before that it was 18.5 and 15.2, resp. So the meter may lie. alot. I changed my oil at 2200mi and saw a significant gain in MPG, probably 30%. My parents have a '10 as well and they get about 23.5 Hwy, all stock 2 dr sport, @ 70 mph. I'm jealous.
|05-03-2011 06:42 AM|
|jk'n||I got better mpg on my Sahara unlimited stock averaging about 20. The Rubicon Unlimited averages 18.5 when nothing is in tow and that is with my roof rack. Without the roof rack it goes up to 19.|
|05-02-2011 08:32 PM|
I get better gas mileage in my gas-guzzling 402ci Corvette than I do my Jeep.
But then again, I am certain my Speedometer has not been reset to compensate for family-sized flotation devices, know as ProComp X-Terrains.
What I did to really get a better understanding of fuel efficieny (or in this case, a serious lack of) was fill up until the gas pump stopped and saved the receipt. Then I filled up over a period of 3 months as a good foundation of driving....Take all receipts and add up all the gallons added into your Jeep over 3 months, then divide your 3 months miles driven by how many gallons used in 3 months. That is a good 3 month basis for mileage.
12 mpg at best, but again, that is without the Speedo being corrected for the 325/60/18s hunkering down the ride. What a surprise it would be if the Speedo WAS corrected! Hahahahahaha......
|05-02-2011 07:40 PM|
Mpg For Speed - Fuel Efficiency Vs. Speed
|05-02-2011 06:00 PM|
|d3digit||in one year on my 2010 JKU stock I eco average 15.5mpg but had never got over 17.8(on highway)|
|05-02-2011 05:25 PM|
I just calculated my gas manually.
The meter says 16.1 mpg
My calculations gave me 14.2 mpg.
75 Mph, soft top up, 2 doors... Cruise control the whole way
the dealership has to be kidding me if they don't check this under warranty.
|05-02-2011 02:25 PM|
I don't know on the random drilling of gas tanks.
Looking up at mine from under the skid plate, there is mighty few accessibility points where a bit would even fit!
There's a couple holes but you'd have to climb under there and spot-locate your drill point, as about 99 % of the tank is metal covered.
|05-02-2011 02:09 PM|
|ModernProspector||I would try a highway run at 65 and another at 60 MPH. I bet there is a fair bit of improvement down at 60, but there may be a sweet spot you can zero in on that you can live with for highway speed between 60 and 70 MPH.|
|05-02-2011 02:07 PM|
id say your readout is messed up or you really are getting bad mileage.
now this is on my readout so i know its not right but it has to close but on a recent 3 hr trip 99% highway i read out about 23mpg with a 4 door rubi, stock tires, smitty built front bumper, superchips set on towing, cruise the whol etime set at the speedlimit. i think you shoul dbe getting better. are you running doors/top?
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