Fuel tank "burping"? And does a DK Custom tank lift affect it?
#31
Yesterday | 10:26 PM
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Joined: Mar 2024
Posts: 457
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From: Colorado
Yes, I agree that the most accurate measurement of an individual owner's MPG is achieved by:
- simply starting with a full fuel tank (filled via whatever method you want to use, as long as you are reasonably consistent on the FIRST and LAST fill),
- zeroing the trip info screen by choosing a new far-away destination that you don't intend to actually visit
- refilling the tank whenever you feel like doing so (if you are interested in ONLY getting the overall MPG for the entire test duration)
- when ready to stop the longterm test, fill up PRECISELY the same way you filled at the start of the test (if you want best possible accuracy)
- Calculate the MPG based on the TOTAL gallons you pit into the tank after starting the test
- Compare that to the MPG claimed by the HD Trip Info Screen, and decide which one you want to believe if they are different.
The flaw in that plan though is that it only gives you your average MPG for the entire test period. No breakdown by speed, which is important if your speeds and traffic situaitons during the tets period are not representative of your normal, OR if your normal is a mix of city, suburban and highway, but you are planning a long multi-day hgihway trip with minimal city or subrban riding, and at speeds that are not the same as during your test. It alos does not tell you how far you can go before running out of gas if you find yourself on a segment of highway you are not familiar with that has few gas stations.
I was hoping to get more detailed info that I could use to do some long trip planning, and to make speed versus MPG decisions.
Jim G
- simply starting with a full fuel tank (filled via whatever method you want to use, as long as you are reasonably consistent on the FIRST and LAST fill),
- zeroing the trip info screen by choosing a new far-away destination that you don't intend to actually visit
- refilling the tank whenever you feel like doing so (if you are interested in ONLY getting the overall MPG for the entire test duration)
- when ready to stop the longterm test, fill up PRECISELY the same way you filled at the start of the test (if you want best possible accuracy)
- Calculate the MPG based on the TOTAL gallons you pit into the tank after starting the test
- Compare that to the MPG claimed by the HD Trip Info Screen, and decide which one you want to believe if they are different.
The flaw in that plan though is that it only gives you your average MPG for the entire test period. No breakdown by speed, which is important if your speeds and traffic situaitons during the tets period are not representative of your normal, OR if your normal is a mix of city, suburban and highway, but you are planning a long multi-day hgihway trip with minimal city or subrban riding, and at speeds that are not the same as during your test. It alos does not tell you how far you can go before running out of gas if you find yourself on a segment of highway you are not familiar with that has few gas stations.
I was hoping to get more detailed info that I could use to do some long trip planning, and to make speed versus MPG decisions.
Jim G
Then there is highway. I've taken multi day trips. I usually will burn the first tank and check... To see how it is then. It's usually a little better. It still doesn't matter, because a tank will do 200-220 miles, and stopping at 150+ is what we generally do. There have been a couple times I've stretched it too far... But, stop engine braking, stop speeding, coast when you can. Really extends things. I've never run out of gas... Ever... In my entire life.
What I suggest is do several test, over several tanks, with every possible variation. Start with level ground, collect milage data for ever 10 kph from say 30 kph to 180 kph. Then find mountain passes and take tanks of gas so you can fill up at the top and collect data for ever degree of grade from say 0 to 8%. You can double your efficiency by going down same grade and filling at bottom to collect down hill data too. While you do that you can collect wind data and fill in those test for wind conditions. After that, you will have to repeated all the tests without wind data, with varying wind... Say 8 directions. .. N/ne/e/se/s/sw/w/nw. And do all that again for winds over 10 kph from say 10-120kph. Then you can put all that in a giant spread sheet and presisely calculate expected KPL on any given route crossrefrenced with topo maps.
Or you can just track kilometers driven per liters consumed averaged out over several tanks of normal driving to have a reasonable expectation of how far a tank will take you and stop at a reasonable distance to fill up.... Or, you could carry some extra gas to cover a reasonable margin of error... Or, you could just stop at every station you come to and never worry about it. It's just not a difficult problem to solve to figure out where to stop on a trip. And it doesn't require a slide rule or a calculator.
Last edited by Powermankw; Yesterday at 10:31 PM.
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