davidblythe
Registered user
ta for the post pathfinder, will ask at Vines about it
33mpg is my GSA Broke
- Thread starter davidblythe
- Start date
I live at over 1000 feet above sea level so perhaps I am IN the mountains (or at least cloud cuckoo land!.) I will try and get a reading on fuel consumption (i suppose a humble GS can only be better than a GSA?I'm no scientist but i've found my bike is pretty good on fuel in the mountains..i alway's assumed it was down to a mix off things , aerodynamic's not being as big a deal at lower speed , BMW's supposed very advanced engine management calibrating superbly for the change in altitude and the fact you usually have gravity helping you for 50% of the time
Dellis
Registered user
Brian,
I'd be interested to see what you end seeing as a return. FWIW I had a GS prior to my GSA, did just short of 50,000 on the GS and am around 26,000 on the GSA and although BMW publish lower fuel economy figures for the GSA I haven't really noticed any difference.
If you fancy a long run to benchmark your MPG then come and join us for a few beers.
Dave
Thank you for your kind invitataion
At a constant 56 mph a GS will do 66 mpg and at at steady 75 mph it ll do 51 mpg. These are the official figures required by law. You can soon realise that it is opening and closing the throttle and using the brakes that affects mpg - far far more than altitude/petrol quality/weight of load carried, temperature and atmospheric pressure, air resistance, etc.etc.
Unfortunately the distance is 1404 kms and at the moment my drive (just over 140 metres downhill) is ice covered so I doubt if I could survive 1404 metres! If you want to try it in the other direction I will be happy to offer you accommodation.
At a constant 56 mph a GS will do 66 mpg and at at steady 75 mph it ll do 51 mpg. These are the official figures required by law. You can soon realise that it is opening and closing the throttle and using the brakes that affects mpg - far far more than altitude/petrol quality/weight of load carried, temperature and atmospheric pressure, air resistance, etc.etc.
I find the GS is amazingly economical at medium speeds, but burns fuel exponentially as speed increases (which all vehicles will do as it takes @4 times the power for dounle the speed, but the GS is a brick so probably fares worse)
Engines are most efficient at peak torque, but this is not always a good cruising speed - peak torque on my ZZR1400 was at 150mph in top, also this is peak torque at 100% throttle, peak torque may move up or down on lower throttle openings, anyway there are many factors.
The closed loop part of the fuelling (where the ECU measures and alters fuelling) is small on most bikes (not sure of BMW specifics) but often the bike will be going of a fuelling map and not adjusting mixture based on O2 readings (although air temp / engine temp alters fuelling, the current O2 reading may not)
On the closed loop it will be very efficient - probably why the bikes are so good on steady runs, other twins I have owned have guzzled gas.
With the poor aerodynamics and (compared to faster sportsbikes) low gearing the GS is going to get punished on fuel consumption at higher speeds.
My ZZR did 100mph at 5k, just of idle really, with its small low frontal area, a huge fairing and wind tunnel tested bodywork easing it through the air it was pretty good on fuel, 90mph two-up cruising returning about 43-44mpg, however it was barely any better at 70mph, the best I ever recorded was 48mpg on a steady run from work to home (trying to get good fuel consumption and keeping the speed below 80) and I came to the conclusion it was not worth slowing up, for the few pence I saved I would rather get there quicker.
I found the GS avaerages high 40's if ridden at the sort of speed the ZZR would get 45mpg, but I happened to be riding the old work-home route on the GS so reset the computer and rode at a simlar pace, it averaged nearly 60mpg!!!
Knocking 20mph of the Z's cruising speed only saves about 7% fuel, on the GS it seems to save about 20%. Very significant.
As to the Alps, over a tour of several thousand miles my averages seem to be stable, if my old bike did use more fuel in the mountains / less fuel in Europe it was not that siginificant.
Engines are most efficient at peak torque, but this is not always a good cruising speed - peak torque on my ZZR1400 was at 150mph in top, also this is peak torque at 100% throttle, peak torque may move up or down on lower throttle openings, anyway there are many factors.
The closed loop part of the fuelling (where the ECU measures and alters fuelling) is small on most bikes (not sure of BMW specifics) but often the bike will be going of a fuelling map and not adjusting mixture based on O2 readings (although air temp / engine temp alters fuelling, the current O2 reading may not)
On the closed loop it will be very efficient - probably why the bikes are so good on steady runs, other twins I have owned have guzzled gas.
With the poor aerodynamics and (compared to faster sportsbikes) low gearing the GS is going to get punished on fuel consumption at higher speeds.
My ZZR did 100mph at 5k, just of idle really, with its small low frontal area, a huge fairing and wind tunnel tested bodywork easing it through the air it was pretty good on fuel, 90mph two-up cruising returning about 43-44mpg, however it was barely any better at 70mph, the best I ever recorded was 48mpg on a steady run from work to home (trying to get good fuel consumption and keeping the speed below 80) and I came to the conclusion it was not worth slowing up, for the few pence I saved I would rather get there quicker.
I found the GS avaerages high 40's if ridden at the sort of speed the ZZR would get 45mpg, but I happened to be riding the old work-home route on the GS so reset the computer and rode at a simlar pace, it averaged nearly 60mpg!!!
Knocking 20mph of the Z's cruising speed only saves about 7% fuel, on the GS it seems to save about 20%. Very significant.
As to the Alps, over a tour of several thousand miles my averages seem to be stable, if my old bike did use more fuel in the mountains / less fuel in Europe it was not that siginificant.
casperfelix
Registered user
Don't murder my 2008GSA but I get a move on and the average fuel consumption is always around 50 mpg - which I'm very happy with.
I think its a square law, double the speed and you square the drag. At 20mph the figures are 40 and 400 but at 50 double would be 100 but square it and you get 2,500. These are just figures and are only to show the way the numbers jump up at higher values.
Once you get past 70mph'ish the aerodynamics of a GS start to have a major cost in fuel consumption.
.
Figures and theories
".....Once you get past 70mph'ish the aerodynamics of a GS start to have a major cost in fuel consumption....." I don't think that the figures (51 mpg at a steady 75 mph show this.) it is more a question of accelerating and braking; If you can ride at a steady 75 mph (which is probably indicated at about 80 mph) you will obtain reasonable fuel consumption.
Perhaps more to the point, if you have a GSA tank full to the brim, 33+ litres, (7+ gallons) you should be able to ride it non stop for about 350 miles - but that means over four and a half hours without a break - not advisable even here on our empty autoroutes;
.
".....Once you get past 70mph'ish the aerodynamics of a GS start to have a major cost in fuel consumption....." I don't think that the figures (51 mpg at a steady 75 mph show this.) it is more a question of accelerating and braking; If you can ride at a steady 75 mph (which is probably indicated at about 80 mph) you will obtain reasonable fuel consumption.
Perhaps more to the point, if you have a GSA tank full to the brim, 33+ litres, (7+ gallons) you should be able to ride it non stop for about 350 miles - but that means over four and a half hours without a break - not advisable even here on our empty autoroutes;
.
Dellis
Registered user
But I ride in the same way be it at altitude or not and I still see an improvement in MPG, maybe I should start a poll to see how many Tossers see similar improvements.
Brian I have a similar problem, I live on a farm about 1/2 mile away from the public road via a concreted drive which is currently covered in hard packed and frozen snow. Hopefully I'll be able to liberate my bike in time for Boxing Day....
Thanks for the offer of accommodation. Had I not already made plans to camp in the lakes I may well have taken you up on it. If it's an open offer then I'll make an effort.
Cheers
Dave
CliveS
Registered user
MPG
I get between 55 and 58 MPG.
The bike is 3 years old and done 19,000 miles. I ride mostly 2 up but when I am on my own with the boys we push it a bit. Mixed traffic and winding roads. I have noticed on long runs at 70 MPH, 2 up, on Freeways we drop down to 53 MPG
All the best and saf3e riding
I get between 55 and 58 MPG.
The bike is 3 years old and done 19,000 miles. I ride mostly 2 up but when I am on my own with the boys we push it a bit. Mixed traffic and winding roads. I have noticed on long runs at 70 MPH, 2 up, on Freeways we drop down to 53 MPG
All the best and saf3e riding
iftikartaxis
Registered user
fuel consumption
the wife and i always go together when ever the bike goes out
the bike seems to run best when fully loaded and fuel consumption is good
ride 70mph most times slower like it to rev about 3k rarely about 4k
plugs beautiful colour standard pipe without cat K&N airfilter did have briss plugs in now standard bosch make sure your stick coils are ok one of mine went down and it was hardly noticeable
yet when i changed new coils different bike
happy new year 2011 bring it on
the wife and i always go together when ever the bike goes out
the bike seems to run best when fully loaded and fuel consumption is good
ride 70mph most times slower like it to rev about 3k rarely about 4k
plugs beautiful colour standard pipe without cat K&N airfilter did have briss plugs in now standard bosch make sure your stick coils are ok one of mine went down and it was hardly noticeable
yet when i changed new coils different bike
happy new year 2011 bring it on
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