Full RPM or high idle? Bush hogging fuel efficiency

[JDgreen227]

Domush, some time ago I started a thread asking how much of a fuel savings I would get with my Deere by removing 500 pounds of FEL weight when I was using my tractor to mow, rather than leaving the FEL installed...nobody seemed to be much in agreement about that either.

 

[jejeosborne]

so yeah.. I'll take that bet. I'm used to looking like the swamp thing after a good day of mowing.. only thing clean is what's under my glasses and ear plugs.
)

Why?
I could mow it just as fast before church and not even require a shower. You must have an addiction to create dust for no apparent reason or is there? My lungs and brain are always trying to help each other out when possible.

 

[Redneck in training]

Power generated by the engine is always equal to power required to perform the task. Fuel consumption is proportional to power required multiplied by time. Mowing at lower rpm will not save fuel because it takes longer to perform the task. The tractor wear will be also about the same. The pistons in the cylinders travel at lower speed but for longer time. This assumes constant efficiency of the engine regardless of rpm though. The specific fuel consumption curve suggests that the highest efficiency is reached at about maximum torque (PTO speed) so mowing at lower speed might in fact use more fuel. Noise and stress on the mechanical components of the tractor is another issue.
Case study are cars with modern auto transmissions. They are hard to beat in fuel consumption by identical car but with manual transmission because of automatic keeps the rpm in around the region of the best fuel consumption. Manual transmission has theoretically lower losses but most drivers don't keep the rpm at the best fuel consumption (in fact it is impossible unless the trany has many gears).

 

[bigbull338]

i run my rpms at 1800 to 2000 bushhogging as i find i get a better cut.i have never ran at full 540 speed.

 

[Soundguy]

Why?
I could mow it just as fast before church and not even require a shower. You must have an addiction to create dust for no apparent reason or is there? My lungs and brain are always trying to help each other out when possible.

i simply don't think you may have ever mowed in weeds 8' tall?? on an open station trike? with some rain? debris do! land on you simply from driving forward. with no front axle on a trike, ( trike.. remember.. narrow front!! ) the front of the running board is the first contact point for nearly 60% of the stuff hitting the front facing of the tractor.. those tall seedy, weeds then slap ME as they hit the running board and curl over.

I sometimes think you purposefully try to distort what you read / vs what i typed?

i don't think it's possibly to mow for a day in those conditions, and then come out clean and smelling like a rose.. unless you can also walk on water.. raise dead people and started a religion a couple thou years ago.

if the latter is true.. .. my appologies.. don't smite me

 

[Soundguy]

oh.. don't be interjecting any logic into this now.. that'll just get you branded a stupid dirty moron like jejeosborne implies i am..

Power generated by the engine is always equal to power required to perform the task. Fuel consumption is proportional to power required multiplied by time. Mowing at lower rpm will not save fuel because it takes longer to perform the task. The tractor wear will be also about the same. The pistons in the cylinders travel at lower speed but for longer time. This assumes constant efficiency of the engine regardless of rpm though. The specific fuel consumption curve suggests that the highest efficiency is reached at about maximum torque (PTO speed) so mowing at lower speed might in fact use more fuel. Noise and stress on the mechanical components of the tractor is another issue.
Case study are cars with modern auto transmissions. They are hard to beat in fuel consumption by identical car but with manual transmission because of automatic keeps the rpm in around the region of the best fuel consumption. Manual transmission has theoretically lower losses but most drivers don't keep the rpm at the best fuel consumption (in fact it is impossible unless the trany has many gears).

 

[Redneck in training]

oh.. don't be interjecting any logic into this now.. that'll just get you branded a stupid dirty moron like jejeosborne implies i am..

I developed immunity to to be called moron long time ago.

 

[Soundguy]

I developed immunity to to be called moron long time ago.

you married too then eh?

 

[Redneck in training]

you married too then eh?

Oh yee. Second time.

 

[Soundguy]

Oh yee. Second time.

same here