KM's to empty?

[apex]

Has anyone tracked their KM's from when the gas light turns on to when the tank actually runs dry? I've been driving with the pin past the red for two days now.

So far, I've managed 120 km's from when the indicator turned on. This normal?

Greg

[thunderstruck]

You’re due for a fill up! I've done 115km with the light on and my avatar is a pick of the fill up. 71.222L in a 72L tank. I'd say get to the gas station.

Although it is fun to see how far you can go I would not unless you have to. If you let your fuel pump run dry you can burn it out. That my friend will be a pain in the arse repair.

[apex]

Just hit 125km and filled up. 70.9L

Damnit I had 1.1L to go!

[Abrasive]

Did you actual have 125km?
Did you put the correct speedo gear in after putting your 33's on? If you didn't, you only had about 110km.

In either case, you're a braver man than I. I ran out of gas once, and vowed to never do it again.

Kris

[apex]

I've got a set of 29's AT's for the city. Swap them out as needed. The 10L Jerri Can gave me a little bit of confidence. (and a wicked buzz!)

Now... i gotta figure out what 125km translates into when in 4lo the whole time. Any guestimates?

Greg

[RckyMtnTJ]

Actually if he didn't replace the speedo gear he will go further than whats on his odometer.  More like just shy of 140km.

[FeatherFoot]

You've been touching on one of my pet peeves with vehicles and speedometers.   :x In an age where we can GPS a location on an area the size of earth to within a meter or so, it strikes me as bazzare that the best the vehicle manufacture's will do is adjust a speedo if it varies more than 10%.  At a hundred klicks, that means two vehicles registering 100 k's could be travelling at 20 KPH's difference.   :shock: That's a significant impact in a collision.  I know tire wear is a valid reason for variance, so maybe we need to attach an optical mouse to one of the diff housings and track speed and distance with more accuracy.  

But as it relates to your questions, over and above vehicle factory deviations in speedos,  :twisted: and our inevitable playing with tires and diff ratios, the notion of any consistancy with vehicles on something as arbetrary as a low fuel warning, is OK conversation, but I wouldn't use it for anything beyond that.

For off road fuel consumption, we operate more like farm or industrial equipment, and it probably makes more sense to think of liters per hour based on expected conditions.   :idea: It might be interesting to start a thread asking for results in liters per hour on specific trails in various conditions, and see if the results provide anything to work with.

[apex]

Re: Litre/hour
Go giver Bill Nye.

Re:"OK conversation"
Did you mean 1)my inquiry is invalid  2)the results are so abritrary that discussing it could be deemed useless or,  3) idle chat about mileage should not be posted on this site?



 :shock:

[Dave]

I don't profess to be a mind reader but I understood him to mean #2. Everyone's Jeep will vary so widely that I would hate for someone else to feel they have a 100KM "comfort zone" when the low fuel light illuminates.

[Da_chopper]

Also depending on the year of your jeep, the light might come on with different amounts left in the tank. I think for my 05 the light comes on with only 7L left.

Man, it would it be sweet if I could get 100 km out of that  

[FeatherFoot]

The more varied the discussion the better.  Most all of it eventually boils down to benificial points of view.  Plus, you never what new ideas or concepts could result.
 
Since we like to be safety aware within the club, my comments were only ment to caution against placing too much weight on hard numbers with offroad vehicles and all the variables that go with that environment.

I don't profess to be a mind reader but I understood him to mean #2. Everyone's Jeep will vary so widely that I would hate for someone else to feel they have a 100KM "comfort zone" when the low fuel light illuminates.

Consider my mind read.

[TJ54]

You've been touching on one of my pet peeves with vehicles and speedometers.   :x In an age where we can GPS a location on an area the size of earth to within a meter or so, it strikes me as bazzare that the best the vehicle manufacture's will do is adjust a speedo if it varies more than 10%.  .

That bothers me too. I believe I saw an ad somewhere about a GPS speedometer. The big selling point being you could change tires and/or gears ratios at will and it would always give you the correct speed. Did anyone else see that?

Next question.How accurate is the speed measurement with my Etrex unit. My Tj Is right on the money comparing the speedo with the gps. Even though I have 31'' tires and have never changed the speedo gear, it was stock with 205/15 ? and had 235/75 when I bought it.

My wifes '98 ZJ, which is completly stock original size tires is out to lunch. GPS says 100KPH and speed says a hair under 90. But when I drive the ZJ the speedometer reads what I expect compared with other vehicles eg. about 110 on deerfoot, or 90 ish on crowchild in the 80 zone.

The other thing is the gps seems to compare accurately with the odometer in the ZJ over short and longer (100km) distances.
Which confuses me entirely, as I thought the speedometer and the odometer are ran off the same gear in the tranny.
So my conclusion is measuring your speed with a GPS is fairly inaccurate :?  :?   But I don't believe that. What am I missing??

As far as the original question, I know I have gone about 75km past the empty point. But it makes me kinda nervous. I usually gas up when I have 1/4 tank left.
I believe gas tanks usually hold a little more than the manufacturer states, You could probably get an extra 4 or liters above that spec. Unless you have dented the tank on the trail , then who knows :wink:

[RUBI]

Go with the GPS, I have an E-Trex as well, and if you check the specs, they are accurate to 1/10 of km/hr or 1%. Don't think you can get much more accurate than that  :wink:

[FeatherFoot]

I,ve compared my GPS (Garmin e-trex) to a corrected speedo on the highway, and I don't question it's accuracy.  It just occured to me that for trail use, unless there is logic in the device to account for elevation change, speed and distance would not be accurate in a GPS in hilly/mountainous terrain.  My GPS displays altitude, but I've never attempted to compare it to my speedo in hilly terrain to see if it factors elevation changes into the speed or distance.

[TJ54]

I am going to have to take the ZJ in to get the speedo checkednow, it is just one of little things that irritate me.
I ahve been checking the gps for accuracy on the highway so elevation changes should have a minimal affect.
Bob, did you know the the elevation readings in your gps should not be trusted too much. I have left a gps unit sitting in the same spot for a while. and seen elevation changes of as much as 600 ft without moving, If accuracy in elevation is important to you, a gps unit with a built in barometer is the way to go. You just have to baseline them everytime you use them as barometeric presure changes, which I don't believe is a big deal at all. If you know the elevation at your home, you can set the baseline when you head out. I don't know how you would adjust it on the trail if the barometric pressure changes throughout the day. the guys at  http://www.gpscentral.ca/  would be able to help with that.