2009 C 14 Typical MPG's - 32?

[C1xRider]

+1!

I can get 32, if I run the wheels off of it, but usually it's around 36 to 38 with back roads and trying my best to keep it 'under the RADAR'.   

2010, non-ECO mode, 150lb rider.

[tonedeaf]

I have an '11. I am 170 and live at 8,600'. I get 41 - 45 riding aggressively in the twisties. I get 45 riding two-up at a sane pace. Riding solo at ~75 on the super slab with eco on I get 50+.

I have about 20 miles of city driving (while leaving town after buying the bike) so I do not have any city numbers. I believe the big key to good mileage is spending as much time as possible in 6th gear.

[stevewfl]

Wish mine would get 32 MPG, would be a good excuse before the warranty is up to push it over a cliff and buy the beemer 

[danl]

I only have a little over 1000 miles on my '11 that I brought home on 10/1, so far averaging 40.8mpg, though I expect it to decrease now that I'm allowed to rev it some more. 

I run eco mode most of the time and had a stretch last weekend where we were stuck in a line of traffic and I was showing over 50mpg going 50 in 4th gear, which I thought was good. My last 2 tanks have averaged 38mpg, which is better than I've expected for a bike like this. A good tank was 38mpg on my Vulcan 1600, it was usually 35 or so. 

[martin_14]

I've gotten anything between 26 and 55 mpg out of one given tank.
For some reason that I'm still hunting, the hotter the weather the better the fuel economy (Fretka? Brian? c'mon, guys!).
At high altitude you loose some mpg.
And regardless all that, the obvious enemy is simply your own right hand... 
Trying to get somewhere quickly using the Autobahn will not only drop you mpgs to the low 20s, but also the rear tire will be loosing some weight rapidly.

[VirginiaJim]

Didn't we already have numerous MPG threads?

Anyway... I seem to get 42 average on my 2011 on mostly highway.  I never use "eco" mode, but I also rarely accelerate really hard.  I weigh 160lbs, in low altitude, and I use the correct gas.

I wouldn't say the word 'numerous' but it does come up periodically.

[gPink]

Wish mine would get 32 MPG, would be a good excuse before the warranty is up to push it over a cliff and buy the beemerHONDA

fixed it for ya

[redbarber]

Didn't we already have numerous MPG threads?

Anyway... I seem to get 42 average on my 2011 on mostly highway.  I never use "eco" mode, but I also rarely accelerate really hard.  I weigh 160lbs, in low altitude, and I use the correct gas.

How much do you weigh at high altitude?? 

[Jeremy Mitchell]

I've gotten anything between 26 and 55 mpg out of one given tank.
For some reason that I'm still hunting, the hotter the weather the better the fuel economy (Fretka? Brian? c'mon, guys!).

The hotter the air the thinner it gets so it takes less fuel to get the right mix.  The colder the air the more fuel it takes.  This is how is has been explained to me anyway.


Have you ever noticed on a cold day that the front end feels a little lighter when you are on the throttle hard?  Ram air on a cold day is a fun combo.

[Aussie in AZ]

How much do you weigh at high altitude?? 

A little less than if he were fatter


Aussie

(42mpg av. I ride every day to work)

[Frontier]

The high altitude is what's killing your mileage.
At 7000 feet your engine is only developing about 72% of rated horsepower.
It takes more fuel to operate the bike at a given speed than at sea level.
My '09 is averaging 41.2 mpg two up at my elevation of 1100 feet here in Arkansas.

[maxtog]

I have an '11. I am 170 and live at 8,600'. I get 41 - 45 riding aggressively in the twisties. I get 45 riding two-up at a sane pace. Riding solo at ~75 on the super slab with eco on I get 50+.

Generally, at high altitudes, gas mileage should be worse.  This is especially true on a FI engine with no O2 sensor.  I am surprised you can get "50+".

[maxtog]

How much do you weigh at high altitude?? 

  I wish I weighed about 15 lbs less at ALL altitudes!

[Mister Tee]

I've gotten anything between 26 and 55 mpg out of one given tank.
For some reason that I'm still hunting, the hotter the weather the better the fuel economy (Fretka? Brian? c'mon, guys!).
At high altitude you loose some mpg.
And regardless all that, the obvious enemy is simply your own right hand... 
Trying to get somewhere quickly using the Autobahn will not only drop you mpgs to the low 20s, but also the rear tire will be loosing some weight rapidly.

The engine is generally running hotter, which is thermodynamically more efficient when it is hot outside.  That's the primary reason for better hot weather efficiency.  Also, depending on the IAT correction factor, you may be running a leaner mixture.

But you should generally GAIN mileage at high altitude, not lose it.  Assuming the ECU correctly adjusts the fuel mixture for altitude via the MAP sensor, you will be running wider open throttle due to the less denser air, which is more more efficient than running at a more closed throttle at sea level.  Also, aerodynamic drag is reduced at high altitude as well.

That said, the fuel map is also a function of TPS.  If the altitude fuel trim correction doesn't account for the more open throttle setting, you COULD be getting an overly rich mixture at altitude.

[Mister Tee]

The high altitude is what's killing your mileage.
At 7000 feet your engine is only developing about 72% of rated horsepower.
It takes more fuel to operate the bike at a given speed than at sea level.
My '09 is averaging 41.2 mpg two up at my elevation of 1100 feet here in Arkansas.

Yes you will lose horsepower, but it does not take more fuel to operate the bike at a given speed than at sea level.  It takes exactly the same amount of fuel to develop the same amount of horsepower, and less horsepower to move the bike at the same speed at high altitude due to the reduced air density.

[Frontier]

Yes you will lose horsepower, but it does not take more fuel to operate the bike at a given speed than at sea level.  It takes exactly the same amount of fuel to develop the same amount of horsepower, and less horsepower to move the bike at the same speed at high altitude due to the reduced air density.

At 7000 feet the thin air density drag effects would be hardly measurable at legal speeds and have no real effect on mpg vs what is experienced at sea level.
At 160 mph-yes.
To develop the rated 153 hp at 7000 feet will require the throttle to be opened further than at sea level. Same goes for maintaining 60 mph or a given load on the engine. Let's say it requires 20 hp to move our bike at 60 mph at sea level. At 7000 feet it will require the throttles to be opened further to produce that 20 hp because of the thinner air.
Basically the volumetric efficiency is less at 7000 ft requiring the throttle to be opened further to maintain the needed power vs what is required at sea level.
With carbs the effect is more pronounced.

[Mister Tee]

At 7000 feet the thin air density drag effects would be hardly measurable at legal speeds and have no real effect on mpg vs what is experienced at sea level.
At 160 mph-yes.

At 80 mph it would be noticeable too - bikes have terrible aerodynamics.  Even at speeds where it is insignificant, it's still there.

To develop the rated 153 hp at 7000 feet will require the throttle to be opened further than at sea level.

The throttle is already wide open at sea level to develop the rated 153 hp.  You would need a turbocharger to develop the full rated hp at that altitude.  It would be accurate to say that in order to develop 100 hp at 7000 feet, you would have to open the throttle further than you would to develop it at sea level.  I think that's what I already said.

Same goes for maintaining 60 mph or a given load on the engine. Let's say it requires 20 hp to move our bike at 60 mph at sea level. At 7000 feet it will require the throttles to be opened further to produce that 20 hp because of the thinner air.

Yes - but but not MORE FUEL.  You have to open the throttle more to achieve the required air mass flow for a given power.  I think maybe that's where the confusion is.  Air pressure decreases at the rate of one inch mercury for each 1,000 feet of altitude.  You have to open the throttle to compensate for that drop in pressure, and decrease in density.  Modern EFI systems adjust the TPS signal range as altitude increases so that additional fuel isn't added.

Basically the volumetric efficiency is less at 7000 ft requiring the throttle to be opened further to maintain the needed power vs what is required at sea level.

Piston engines run most efficiently at wide open throttle, in terms of BSFC.  According to engine design textbooks, anyway.  More open throttle, same air flow, same fuel flow = greater volumetric efficiency.

With carbs the effect is more pronounced.

Carburators run richer with altitude.  The idle mixture is a fixed fuel flow.  The main jets will feed at a rate proportionate to the air flow, so throttle position doesn't affect the mixture.  However, carburators cannot automatically adjust for the decrease in density with altitude.  This is why the mixture control is strictly manual in aircraft carburators.

A modern EFI system with either an O2 feedback system, or map offsets for altitude density and throttle position should be able to maintain a constant air fuel ratio as altitude increases.

[booger]

I'm on my 27 motorcycle and have never worried about my gas mileage.  I've worried about running out of gas, but never the MPG

[ZG]

I'm on my 27 motorcycle and have never worried about my gas mileage.  I've worried about running out of gas, but never the MPG

    

[Summit670]

I have a c10 but my 2c is this -

Sounds like these mileage figures, or a lot of them, may be coming from the digital readouts.  Maybe calculate manually will produce diff results to some degree.

I have not heard anyone mention which windshield they have or what position (up, down, middle) they mostly run it in.  I'm sure the cee-baily in the up position is pushing a lot of air compared to the stocker in the down position.

Next, especially true in my pickup - driving in the mtns I get better gas mileage.  I figure it is because going uphill I'm getting like 3mpg but going downhill I'm getting like a zillion, so when the two are averaged together the mpg is better.