shuswaper
Well-known member
Thanks for that Mississippi ! I always knew that my own experience (anecdotal evidence) was not a figment of my imagination. Me thinks you have put the issue to rest with your learned response. :assassin:
Gas mileage gone WAY down
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twowheelnut
R.I.P. Our Motorcycling Friend
As the surrounded General once said, "Nuts!" Ambient temps may have a wee bit of an affect on mileage, but additives, or lack thereof, will have greater effect. The only thing that will affect your mileage 'greatly' that has nothing to do with the fuel, and assuming equal machine settings, is wind and elevation.
So, the Iggmeister is correct. The rest of you can go pound cold sand. :bleh:
By the way, where's Tarzan when you need him for this kinda discussion?
Third paragraph from bottom.
:****:
So, the Iggmeister is correct. The rest of you can go pound cold sand. :bleh:
By the way, where's Tarzan when you need him for this kinda discussion?
Third paragraph from bottom.
:****:
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SkooterG
Purveyor of Crooked Facts
I am with Iggy and the 'Nut on this one. (God help me) Where's the math?
No doubt, everything you state is true, but without any context, where does it all fit in?
I am going with winter blend of gas being one of the dominating factors. Prove it to me otherwise. With fact, not theory.
Funny how not riding my bike today because I have a cold (pun unintended) and not riding.
I did find this figure on temperature that I'm going to guess is a bigger effect on mileage than the air temperature mixture density thing......is from Click and Clack that says:
I also did some more checking and I think the temperature density (excluding humidity) affects much. I think it is the same as elevation adjustments. See a tuner's calculator. I can't find any calculator on fuel economy, but don't think it's a factor because nobody has bothered tuning a calculator. A colder, more dense air charge is like dropping elevation . Internal combustion engines don't get significantly different mileage with different elevations.......unless you consider serious speeds where you need to calculate deltas of the squares of wind resistance.
....yes, I'm bored.
I did find this figure on temperature that I'm going to guess is a bigger effect on mileage than the air temperature mixture density thing......is from Click and Clack that says:
So, from 90 to 40 is 5 psi.....which has got to be a signficant variable in the mileage equation. (Don't have the math yet for this one)
I also did some more checking and I think the temperature density (excluding humidity) affects much. I think it is the same as elevation adjustments. See a tuner's calculator. I can't find any calculator on fuel economy, but don't think it's a factor because nobody has bothered tuning a calculator. A colder, more dense air charge is like dropping elevation . Internal combustion engines don't get significantly different mileage with different elevations.......unless you consider serious speeds where you need to calculate deltas of the squares of wind resistance.
....yes, I'm bored.
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Knifemaker
Not me
No math here, sorry..but I would say just counting air temps and not barometric pressure, your talking in the 1 to 3 percent range. This has been proven in 1/4 mile runs for various motors, (again, sorry no math at hand) but when talking about normal riding in temps that are say 40 degrees cooler, your likely gaining a bit more power, and burning a bit more gas. I doubt this would account for more than a 3 percent differnence.
However, if in fact the gas you are using produces less power than the gas you are comparing it to (winter/summer) That can make matters worse. Again no numbers...other than these:
My usual around town/ highway mix mpg average durring the warm months was around 37.5 mpg. My trip yesterday , according to the average readout on the dash, netted me 35.5 mpg. Not a big diffrence for roughly a 40 degree drop. The problem here is figures as they say, may vary. If one rides the same route every day , being carefull to go the same speed, stop for the same amount of time, etc... then record each circuits mpg that day, along with the temp and the chemical breakdown of the gas used...we'd have some good numbers to go by. But Jeffs 10 mpg drop due to a 25-30 degree drop in temp seems off somehow and I would guess may not fully indicate all the variables present in his "tests". Right off he said after the mod he was getting poorer mpg. Perhaps he should do some more testing, and change the CO settings back so he can compare them with colder air readings.
The fun of all this is I don't really care what mpg figures I am getting, as this would have been the last thing on the list I cared about when I was considering buying the FJR. My last bike did not have a "average mpg" readout and I never bothered to figure out what kind of milage I was getting. Not a big concern to me, as almost ANY motorcycle gets fairly good gas milage (compared to a car/truck/suv) ..If it has a gas gauge, that's all I really need, low on gas? Stop and get more....
KM
twowheelnut
R.I.P. Our Motorcycling Friend
5 to 9 MPG is insignificant? 25% is nothing to snigger at, my sniffling friend. Witness a trip over Hwy 88 which peaks at 9,680 feet, that I did in April, when the 'oxygenated' (if that's the correct term) fuel was still being sold here in Cali. Prior to that fill-up, I was getting about 44 MPG going up HWY 395 which increases in elevation to 88. Prior to that tank, I gassed in near 0 elevation prior to entering Death Valley and was at my usual 40 MPG. The 88 tank realized a return of 54 MPG and when I hit the basin and gassed, that tank returned 40 MPG again when I refueled on the coast. Speeds were fairly consistent - say 70ish and winds were negligible. This has been consistent for me on this machine and recently proved to be true in the cage, as well.
When the winter gas kicks in I drop 5 MPG in local riding (sea level, for the most part).
S76
Well-known member
I also agree everybody is correct.
But, think of this. You can run a 1500 HP engine on a 1/2" fuel line with gas, but switch to alchohol and that line now needs to be about 1".
There, there's the math. A 1/2 and a 1.
All factors contribute but I think the winter fuel is a big one.
But, think of this. You can run a 1500 HP engine on a 1/2" fuel line with gas, but switch to alchohol and that line now needs to be about 1".
There, there's the math. A 1/2 and a 1.
All factors contribute but I think the winter fuel is a big one.
Still looking for the math on this one my friend. You have so many variables there that's not just the constant of altitude. You're going what seems a net of up in altitude, you're going up and down a bunch with probably different grade profiles, getting gas from different sources (I think), heading in different directions which even with small winds still prevail west to east.
It just bugs me I can't figure out the math on this one. If altitude was a variable on mileage I think I would have found an online calculator or source claiming the effect by now. Until I find it....it's a myth to me.
...Maybe we need to send an e-mail to Mythbusters for them to test it out?
SkooterG
Purveyor of Crooked Facts
Well, I am gonna disagree with Iggy on this one. I firmly believe altitude, or more correctly, density altitude is a HUGE factor relatively on fuel mileage.
You will have to wait until I am actually bored enough for a detailed explanation, but the simple answer is that air resistance goes up with the square of speed. So doubling speed, say from 35mph to 70mph will result in a increase in air resistance of 4 times the original value. And at highway speeds and above, say 50 mph and up, air resistance is the the dominating factor in fuel mileage.
But that is simplistic. There is a lot going on here that have effects, but I still say density altitude and its effect on air resistance is the biggest factor.
You will have to wait until I am actually bored enough for a detailed explanation, but the simple answer is that air resistance goes up with the square of speed. So doubling speed, say from 35mph to 70mph will result in a increase in air resistance of 4 times the original value. And at highway speeds and above, say 50 mph and up, air resistance is the the dominating factor in fuel mileage.
But that is simplistic. There is a lot going on here that have effects, but I still say density altitude and its effect on air resistance is the biggest factor.
I don't disagree at all on air resistance. Unless we just changed subjects and I didn't realize it I thought we were talking about air density as it related to combustion inside cylinders.
....Where's Mr. Austin when you need him?
SkooterG
Purveyor of Crooked Facts
Oh. Guess I got a bit confused with all the salvos of BS flying around. Not sure what the argument is, but here is my take on air density and combustion: The higher the altitude, the lower the air density all other things being equal. The lower the air density, the lower the amount of oxygen present in the air and getting to the cylinder. Since we have a fancy-schmancy high-tech fuel injection system, then also, the lower amount of fuel being injected. Since we have less oxygen (and fuel) being burned, the power being made by the engine will be lower. But even though the engine is making less power, it is a much smaller effect overall on fuel mileage than air resistance.
Yep. Or perhaps even Jestal would have some insight on this topic.
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twowheelnut
R.I.P. Our Motorcycling Friend
Math? Sure, no problem. Professor Nut's Theory of Higher Mileage is simply stated is as follows:
Higher elevation = Better mileage.
Please don't confuse this theory with his revised theory: 'Do Androids Dream of Electric Sheep' and remember, in my world, everything you know is wrong. (Apologies to Firesign Theater for that blantant theft.)
Mythbusters? Mmmmm, only if that red headed dame will sit on my lap while they test, sure.
True.
Not quite, Garlic Boy. Speed is a factor here. If you are running at roughly the same speeds with roughly the same windage, air resistance is roughly nil in the equation of elevational changes and effects on mileage.
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SkooterG
Purveyor of Crooked Facts
Triple Ack!!!
It give's me great pleasure to notify you that you are completely wrong O connoisseur of fine Gerbils!
At any given speed with all other environmental factors (Wind, temp, humidity, grade) other than altitude being equal, air resistance is the primary factor (rolling resistance being the secondary factor) in how much fuel is needed to maintiain that speed- in other words, fuel mileage. And with all those other environmental factors remaining equal, what has a profound effect on air resistance? Altitude. The higher the altitude, the thinner the air (more correctly the lower the density altitude) and therefore the less the air resistance. Less air resistance means less fuel needed to maintain that speed. Less fuel = higher fuel mileage.
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beeroux
Well-known member
SkooterG is right about Density Altitude, but may I add that temperature and humidity also play a role in DA. More heat, more moisture, less density.
Thats why on a hot hot beach or at Badwater in deep summer you feel less air going into your lungs, like you might be at a higher altitude.
Back to my regularily scheduled beer.
GZ
https://futurecam.com/densityAltitude.html
Thats why on a hot hot beach or at Badwater in deep summer you feel less air going into your lungs, like you might be at a higher altitude.
Back to my regularily scheduled beer.
GZ
https://futurecam.com/densityAltitude.html
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conwest
Well-known member
Beeroux, thanks for that (and the "math" so called, that a few must have). Maybe these guys will finally come around. Like I said before: "the colder it gets, the worse the mileage". Now, take out the variables such as: tire pressures maybe too low; xtra warm up time; xtra bulk (clothing); wind and anything else you can think of. What`s left? Ambient temperature and it`s effects on cylinder charging (and the attendant fuel efficiency) as stated by the few of us who have bin dare, dun dat! :assassin: Any of you still foolhardy enough to debate the obvious? :clapping:
madmike2
Shtirrenuppenmeister
Except that you originally indicated it was a "sudden" change. the two factors I suspect are:
1.) Winterized fuel (oxygenated via alcohol) which makes less power.
2.) Colder temperatures will usually mean more dense air. The atmosphere we drive through is a liquid, a more dense liquid will mean that there will be more "resistance" as the bike pushes its way through the air, requiring more power from the engine.
Since the engine is making less power with the winterized fuel, the result is going to be lower gas mileage.
Just my guess....
1.) Winterized fuel (oxygenated via alcohol) which makes less power.
2.) Colder temperatures will usually mean more dense air. The atmosphere we drive through is a liquid, a more dense liquid will mean that there will be more "resistance" as the bike pushes its way through the air, requiring more power from the engine.
Since the engine is making less power with the winterized fuel, the result is going to be lower gas mileage.
Just my guess....
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Howardrg
Well-known member
The higher the altitude the lower the horsepower. To cruse at any given speed at altitude you will use more throttle and therefore more gas.
Howard
edit 17% loss from sealevel to 1,700m [5577 feet]
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Wolfhound
Wildman
Altitude also lowers your tire pressure....
twowheelnut
R.I.P. Our Motorcycling Friend
Air resistance, schmittance. There ain't that much difference in air resistance at sea level versus 3,000 feet, which is where I realize a 5 mpg gain in mileage - all other factors being more or less equal. Besides, your lame science is discounting mechanical friction of the internals, tire pressure, road surface, laden weight, big floppy ears and boogers - which, my Village People loving friend, renders your comments and conclusions, bullshit and thus, mute (yes, I meant to type that). The difference in air resistance for earth bound transportation is minimal. Period.
Oh, yeah,
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