It takes so much energy to move said amount of weight from point A to point B at such a speed. No matter what kind of engine burns the fuel to make the amount of energy required. That is why there is not a big gain in gas mileage from a smaller engine to a bigger one.
phaz4
Veteran
Sled Dog said:
is there any case/reason that smaller sled will be harder to move from point a to point b? is it easier to tow an old bravo or an apex? seems like there are several things that could make smaller sled easier to move. moving a smaller sled should require less energy.
it would be a simple test to take a belt out of a sled and tow it at steady speed using a scale in the tow rope. if you jump on the sled, the force needed to pull the sled will increase even at steady speed.
also, a smaller motor can be more efficient. generally, there is more energy lost to friction and heat loss with the bigger engine at the same power output. there are extreme cases where the smaller motor might do worse. like WFO or at bad spots in the power band, bad efi mapping, etc.
Weight and like you said heat and friction loss on the bigger engine would have to be accounted for.
phaz4
Veteran
Sled Dog said:
there may also be additional losses through the drivetrain because everything has to be bigger to handle the bigger motor power. bigger bearings/etc. means more losses.
if you accellerate and then brake hard the heavier sled will loose more energy due to heat loss through the brakes. it takes more energy to accelerate a bigger mass to a speed. ke=1/2 mv ^ 2. the faster you get the beast going the more energy you have to scrub off to slow down.
another thing is that mpg gets worse the faster you go because wind resistance makes a bigger difference at higher speeds. the phazer might get better mpg just because it is incapable of "wasting" energy by going 90+ mph.
HYFLYR
TY 4 Stroke Guru
We need snow! HAHAHA
Regardless i cant wait to get mine and put a few miles on it. I will tell what i get then, who cares as long as i am having fun. Later boys.
Regardless i cant wait to get mine and put a few miles on it. I will tell what i get then, who cares as long as i am having fun. Later boys.
cmon guys, all i wanted to know was an idea of what the phazer would be like for gas mileage. were all here to share good information and to have some fun. i am a loyal yamaha fan and if my phazer is a littlle harder on gas then i was expecting, well so be it.
phaz4
Veteran
HYFLYR said:
me to!
phaz4
Veteran
pat the rat said:
unfortunately, there isn't any way to know for sure without actually running one.
i am having fun! it will all be water under the bridge when the sleds show up for real. it is just fun to study a tech. issue related to my new toy that i can't have yet.
i was thinking that if you wanted opinion, would it be useful to run a poll with mpg ranges for the phazer and let people vote their guess?
BV1
Expert
Phaz4, I agree and disagree with you to an extent.
If we take what we know about 4 stroke cars.... cruising, for example, we know that at 60 km/h almost EVERY tuned Naturally aspirated 4 Cyl on the market will be pulling better mileage then almost every tuned V8 on the market, as the 4 cylinder is running near peak efficiency and the V8 is wasting more energy moving its pistions then it is actually putting to the road.
We also know that at some point (usually 110 km/h+++) the relationship starts to turn around, as the 4 cylinder leaves its efficiency band (TQ vs RPM ratio) the V8 will still be in its efficiency band, so the V8 or V6 for that matter can be getting the same or better mileage then the I4. At some point as the I4 is leaving its effiency band its going to begin to run really rich too, to protect the engine from detonation (usually at say 60% TPS or 60% throttle) and the V8 or V6 will not be at the point yet.
So yes the I4 has the POTENTIAL to get better mileage then the V6 or V8 but not always, and not as a rule of thumb. Under light to moderate load the I4 performs better/similar, under moderate to heavy load it loses its advantages.
If we transfer this over to sleds, we KNOW smaller engines can burn more gas if you push them too hard, espically in 2 strokes. I've expereinced this on my 550 Supersport. Now as this Phazer is a 4 stroke, I would expect less of a difference between it and the APEX then say a 500cc 2 stroke and a 800cc 2 stroke, due to the non-neccessity of charge cooling etc in the 4 stroke vs a 2 stroke.
The bottom line is, I am hoping under the right conditions the Phazer will be CAPABLE of getting better/similar mileage then an APEX as it SHOULD be CAPABLE.... of this, but I in no way expect it to get better mileage under all conditions.
However if it is not even capable of getting similar mileage.. (even at like 30MPH) then I agree there is something wrong with the tuning or design, EFI is running way to rich.
I am sure Yamaha isnt bragging about the mileage (although they do say the Genesis80 is fuel efficent on their website) for a reason. I think it may be to do with their "Torque enhancing system" on the Phazer. More gears, more places to lose energy.
Time will tell.
-Steve
If we take what we know about 4 stroke cars.... cruising, for example, we know that at 60 km/h almost EVERY tuned Naturally aspirated 4 Cyl on the market will be pulling better mileage then almost every tuned V8 on the market, as the 4 cylinder is running near peak efficiency and the V8 is wasting more energy moving its pistions then it is actually putting to the road.
We also know that at some point (usually 110 km/h+++) the relationship starts to turn around, as the 4 cylinder leaves its efficiency band (TQ vs RPM ratio) the V8 will still be in its efficiency band, so the V8 or V6 for that matter can be getting the same or better mileage then the I4. At some point as the I4 is leaving its effiency band its going to begin to run really rich too, to protect the engine from detonation (usually at say 60% TPS or 60% throttle) and the V8 or V6 will not be at the point yet.
So yes the I4 has the POTENTIAL to get better mileage then the V6 or V8 but not always, and not as a rule of thumb. Under light to moderate load the I4 performs better/similar, under moderate to heavy load it loses its advantages.
If we transfer this over to sleds, we KNOW smaller engines can burn more gas if you push them too hard, espically in 2 strokes. I've expereinced this on my 550 Supersport. Now as this Phazer is a 4 stroke, I would expect less of a difference between it and the APEX then say a 500cc 2 stroke and a 800cc 2 stroke, due to the non-neccessity of charge cooling etc in the 4 stroke vs a 2 stroke.
The bottom line is, I am hoping under the right conditions the Phazer will be CAPABLE of getting better/similar mileage then an APEX as it SHOULD be CAPABLE.... of this, but I in no way expect it to get better mileage under all conditions.
However if it is not even capable of getting similar mileage.. (even at like 30MPH) then I agree there is something wrong with the tuning or design, EFI is running way to rich.
I am sure Yamaha isnt bragging about the mileage (although they do say the Genesis80 is fuel efficent on their website) for a reason. I think it may be to do with their "Torque enhancing system" on the Phazer. More gears, more places to lose energy.
Time will tell.
-Steve
phaz4
Veteran
BV1 said:
i agree with this.
BV1
Expert
I see Yamaha has added this to their description of the Phazer, it wasnt there before:
"The Genesis 80 FI has excellent on-snow fuel efficiency and smooth performance. Yamaha four strokes enjoy miles-per-gallon advantages — fewer fuel stops — cleaner combustion — no two-stroke oil needed. "
-Steve
"The Genesis 80 FI has excellent on-snow fuel efficiency and smooth performance. Yamaha four strokes enjoy miles-per-gallon advantages — fewer fuel stops — cleaner combustion — no two-stroke oil needed. "
-Steve
BV1
Expert
Im hoping we will get some hard numbers soon 
-Steve
-Steve
welterracer
TY 4 Stroke God
Let me just throw this out there..
Do you think they would put out a sled that only holds 8.1 gallons of gas if it only got 10mpg.. ?
My guess is 20+MPG.. under normal hardpack trail riding..
Do you think they would put out a sled that only holds 8.1 gallons of gas if it only got 10mpg.. ?
My guess is 20+MPG.. under normal hardpack trail riding..
yamadoo
Yamadoo is a snowmobile ' aholic'.
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wellter has a good point. Everybody wants about 100 -120 mile min range per tank.
So I think they believe / know it will get about 13 mpg min and more like 15 , for an average. I hope it gets more but am sure it will not get less.
Yamadoo
So I think they believe / know it will get about 13 mpg min and more like 15 , for an average. I hope it gets more but am sure it will not get less.
Yamadoo
Bakemono
TY 4 Stroke Guru
I think you will see at least 20 mpg out of the Genesis 80 FI.
Compared to the other sleds in Yammie's lineup its lighter, has a narrower track and has an engine that is half the size. If it doesnt get at least 20 mpg while cruising trails, something is wrong, IMO.
Compared to the other sleds in Yammie's lineup its lighter, has a narrower track and has an engine that is half the size. If it doesnt get at least 20 mpg while cruising trails, something is wrong, IMO.
