StromTrooper banner

1 - 15 of 15 Posts

·
Registered
Joined
·
63 Posts
Discussion Starter #1 (Edited)
Collected data over 7 tanks of a long but consistent commute.

Conditions
Altitude: 4250ft MSL
TEMPS: Avrg morning temps 78
Avrg afternoon temps 92
This combo of high altitude and high temp results in very high “density altitude” meaning that the actual usable air density is very LOW and the performance of an engine, and the drag at freeway speed are reflective of closer to 7000 feet MSL.
Drag reduction bennifits generally outweigh power loss at altitude meaning in my environment I can get higher cruising speeds with better mpg than someone else could at lower altitude with more power, but much more drag. Example: my best MPG speed up here in hot mountain environment might be 71 but in cold, sea level Alaska it might be closer to 61.


TANK1
Miles: 245.5
Gas added: 4.75 gallons
Computer says 49.7 mpg
Math says 51.6 mpg

Bars 90miles
120 miles
150 miles
170 miles

203 fuel symbol started flashing
230 fuel symbol and last bar started flashing
Engine cut out during right turn at intersection at 243 miles
Sounded like there was virtually NOTHING IN THE TANK WHEN SHOOK yet it took only 4.75 gallons were added to tank that holds 5.28 gallons.

TANK2
Miles: 217.5
Gas added: 3.98 gallons
Computer says 51.8 mpg
Math says 54.6 mpg

Bars 82 miles
110 miles
137 miles
161 miles

210 Fuel symbol started flashing
Last bar never flashed.



TANK3
Lost the first bar at 90 miles I think computer currently says 51.7 miles per gallon
bars. 90 miles
115-122 somewhere
145-150 somewhere
175 miles
184
211 lost another bar and fuel symbol started flashing

Miles: 240.8
Gas added: 4.39
Computer says 52.9 mpg
Math says 54.8 mpg


TANK4
Lost first bar at 67.5 miles and the computer says I am currently getting 49.5 miles per gallon

Miles: 203
Gas added: 3.69 gallons
55.12 mpg
Computer 53.2



TANK5
Bars. 75
118
144
171

205 fuel symbol flashing

Miles: 228.6
Gas added 4.37 gallons
52.3 mpg math
50.4 mpg computer


Tank 6
Miles: 232.1
Gas added: 4.50 gallons
Math 51.57
Computer 50.1 mpg
Last bar never flashed


Tank 7
Miles: 207.7
Gas added: 3.909 gallons
Math 53.13 mpg
Computer 50.9 mpg
Last bar never flashed
 

·
Registered
Joined
·
63 Posts
Discussion Starter #2
I’ll clean it up

I’ll clean up the formatting and standardize data from each tank later but wanted to get this on the forum before the page timed out.
 

·
Registered
Joined
·
63 Posts
Discussion Starter #4
Gas grade and % of ethanol used?


Middle grade. Which is 87 here where I live. I know it’s not needed to use middle grade on the DL650A but when I’m giving it full throttle up a hill and I don’t down shift and cylinder pressures are high it’s a tiny bit of insurance.
I’ll check the ethanol levels.


Sent from my iPhone using Tapatalk
 
  • Like
Reactions: outwestrider

·
Registered
Joined
·
1,070 Posts
I wonder if the trip computer is intentionally off just like the speedo, or if other variables cause it to disagree with the actual math. The differences seem consistent within a few tenths.
 

·
Registered
Joined
·
63 Posts
Discussion Starter #6
I wonder if the trip computer is intentionally off just like the speedo, or if other variables cause it to disagree with the actual math. The differences seem consistent within a few tenths.


I wondered the exact same thing.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
63 Posts
Discussion Starter #7
I wonder if the trip computer is intentionally off just like the speedo, or if other variables cause it to disagree with the actual math. The differences seem consistent within a few tenths.


What reason is the speedo intentionally off? I heard it once but forgot .


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
834 Posts
Collected data over 7 tanks of a long but consistent commute.

Conditions
Altitude: 4250ft MSL
TEMPS: Avrg morning temps 78
Avrg afternoon temps 92
This combo of high altitude and high temp results in very high “density altitude” meaning that the actual usable air density is very LOW and the performance of an engine, and the drag at freeway speed are reflective of closer to 7000 feet MSL.
Drag reduction bennifits generally outweigh power loss at altitude meaning in my environment I can get higher cruising speeds with better mpg than someone else could at lower altitude with more power, but much more drag. Example: my best MPG speed up here in hot mountain environment might be 71 but in cold, sea level Alaska it might be closer to 61.


TANK1
Miles: 245.5
Gas added: 4.75 gallons
Computer says 49.7 mpg
Math says 51.6 mpg

Bars 90miles
120 miles
150 miles
170 miles

203 fuel symbol started flashing
230 fuel symbol and last bar started flashing
Engine cut out during right turn at intersection at 243 miles
Sounded like there was virtually NOTHING IN THE TANK WHEN SHOOK yet it took only 4.75 gallons were added to tank that holds 5.28 gallons.

TANK2
Miles: 217.5
Gas added: 3.98 gallons
Computer says 51.8 mpg
Math says 54.6 mpg

Bars 82 miles
110 miles
137 miles
161 miles

210 Fuel symbol started flashing
Last bar never flashed.



TANK3
Lost the first bar at 90 miles I think computer currently says 51.7 miles per gallon
bars. 90 miles
115-122 somewhere
145-150 somewhere
175 miles
184
211 lost another bar and fuel symbol started flashing

Miles: 240.8
Gas added: 4.39
Computer says 52.9 mpg
Math says 54.8 mpg


TANK4
Lost first bar at 67.5 miles and the computer says I am currently getting 49.5 miles per gallon

Miles: 203
Gas added: 3.69 gallons
55.12 mpg
Computer 53.2



TANK5
Bars. 75
118
144
171

205 fuel symbol flashing

Miles: 228.6
Gas added 4.37 gallons
52.3 mpg math
50.4 mpg computer


Tank 6
Miles: 232.1
Gas added: 4.50 gallons
Math 51.57
Computer 50.1 mpg
Last bar never flashed


Tank 7
Miles: 207.7
Gas added: 3.909 gallons
Math 53.13 mpg
Computer 50.9 mpg
Last bar never flashed

I had the same problem, but my doctor got me on some meds for my obsessive-compulsive disorder.

Incidentally, when I replaced my front tire with a 50/50 tire of the same size but with thicker tread, and larger OD, my odometer and speedometer are now accurate.


Sent from my iPad using Tapatalk
 

·
Registered
Joined
·
347 Posts
Over the 22k plus miles I've had my bike the mpg ranges from a low of around 48 to a high of 60.
Speed and stopping as you might imagine are the biggest factors for moving my mpg up or down.

50-65 mph and not stopping but for fuel will easily return 60mpg even with hard bags and a top box and the givi screen in the up position

Running errands on surface streets in LA and I've seen times where it's like 45mpg.
 

·
Registered
Joined
·
50 Posts
I average 67 mpg.

Commuting at 50 mph max, 40 mile round trip per day, 200 miles a week. At sea level (Southern Maine)
10% ethanol, 87 octane.
Street tires (Michelin Pilot Road 4 trail).
Factory hard panniers always on.

My trip computer always comes up short, saying 58-61 mpg. But the math works out differently.
 

·
Registered
Joined
·
301 Posts
Wonder if I should copy-paste my Excel sheet in here?

51 fill-ups with mileage, miles, cost, and odo readings. Short version is, my '15 XT averages 56.81 mpg with a high of 65.84 and a low of 48.09 mpg.
 

·
Registered
Joined
·
153 Posts
I don't remember the exact number but I believe I got around 250-260 miles out of a tank once. Fortunately it is a long down hill grade into town and I came in on a prayer! Thought for sure I was going to be walking but I made it to the gas station. For what that useless piece of information is worth...
 

·
Premium Member
Joined
·
1,275 Posts
I bounce between 50 and 60 mpg depending on how much I flog the bike and speed. I get about 57 on my commute if I'm good :grin:
 

·
Premium Member
Joined
·
1,275 Posts
I average 67 mpg.

Commuting at 50 mph max, 40 mile round trip per day, 200 miles a week. At sea level (Southern Maine)
10% ethanol, 87 octane.
Street tires (Michelin Pilot Road 4 trail).
Factory hard panniers always on.

My trip computer always comes up short, saying 58-61 mpg. But the math works out differently.
What a great commute and perfect for fuel efficiency!
 

·
Administrator
Joined
·
13,564 Posts
I wonder if the trip computer is intentionally off just like the speedo, or if other variables cause it to disagree with the actual math. The differences seem consistent within a few tenths.
With such a small sample size (only 7 fill ups) it is hard to see the bigger picture.

Here is a graph that compares the actual fuel mileage (based on mileage the bike traveled and fuel filled) vs the trip computer calculation on my 2012 DL650. It is based on three and a half years of riding, 447 fill-ups, 86,714 miles traveled with all kinds of riding but much of it riding to work (roughly 100 mile round trip, about half interstate-type riding, the other half largely secondary roads.)

I ride much of the year when there isn't snow or ice on the road (at least not intentionally) so temperatures ranged from 0°f to around 100°f.

The accuracy of the trip computer largely matches the temperature. It becomes more accurate as the temperature drops:



In the hottest weather the trip computer mileage can read as little as 93% of the actual calculated mileage. At freezing temps it is almost 100% on.

If you are stretching your fuel range based on the mileage you need to know this if you ride in cold weather as that "extra" range you have in warmer weather disappears and you might find you have a cold walk to the gas station to get gas.


While speed (and especially airspeed) is one of the biggest effects on mileage it also tracks the temperature. Mileage is roughly 10 to 20% worse as the temperature drops to freezing or below.

..Tom
 
1 - 15 of 15 Posts
Top