Best RPM for Fuel Economy and FEL work

[Gittyup]

I run mine more in the 1800-2000 range most of the time. When doing loader work or anything not steady state, I use the foot throttle and vary rpm, but rarely go over 2000.

There were comments made by some dealers, implying that using the foot throttle a lot is hard on the injector pump. So, I stopped doing that so much. I still use it, but less.

 

[Jay4200]

There were comments made by some dealers, implying that using the foot throttle a lot is hard on the injector pump. So, I stopped doing that so much. I still use it, but less.

Really? I have a 42HP Kubota with shuttle-shift, and I use the foot throttle all the time, since I like the chop the throttle when shifting with the shuttle. OTOH, I almost always run my Woods 9000 backhoe at full PTO rpm, and I ALWAYS run my 6' snowblower with the throttle wide-open (except when shifting with the shuttle). The blower will clog up in heavy snow at less than full blast, and I like the backhoe to move as fast as it can.

JayC

 

[MichiganIron]

The PTO speed is usually set to maximum torque the engine can produce. It is also the speed of the best specific fuel consumption [ounces/HP/hour]. My tractor has Kubota 1501 engine and I run it above 2000 rpm most of the time but very seldom over PTO speed.

The engines will reach maximum torque below the PTO rated speed (approx 2100rpm). After that, they will reach maximum horsepower at about PTO speed (2500rpm). The torque falls off slightly above the maximum torque rpm as you reach maximum horsepower rpm. Your engine is running most efficiently at maximum torque, which is in the 2100 rpm range. Also, there shouldn't be any need to run above the PTO rating (approx 2500rpm). Extra wear with no gain in horsepower.

For the HST tractors, the hydrostat runs most efficiently at a minimum of 2000 rpms. This allows the system to build to proper charge pressure. So...if you are working a HST, run it between 2000 and 2500 rpm. For shuttle shift or gear tractors, about the same range for maximum torque, or maximum hp.

 

[kidkioti]

I've only done this once or twice. I was getting about 7 hours at or near PTO HP on a tank. Tank never ran dry, but probably close, like 6 -7 gallons. From what I've been reading that is about what to expect, right around .8 - 1 gallon per hour.

Thanks Gittyup - That's about what I come up with. I wonder if anybody else will post their GPH. KK

 

[IslandTractor]

Thanks Gittyup - That's about what I come up with. I wonder if anybody else will post their GPH. KK

Obviously Gallons/hour will vary proportionally with tractor rated HP. I got almost 2 hours/gallon with my CK20 and about a gallon/hr with the DK40se.

 

[Gittyup]

Really? I have a 42HP Kubota with shuttle-shift, and I use the foot throttle all the time, since I like the chop the throttle when shifting with the shuttle. OTOH, I almost always run my Woods 9000 backhoe at full PTO rpm, and I ALWAYS run my 6' snowblower with the throttle wide-open (except when shifting with the shuttle). The blower will clog up in heavy snow at less than full blast, and I like the backhoe to move as fast as it can.

JayC

Yes. Common sense, really. Rack going back and forth a lot creates more wear and tear. How much? Design and fuel quality decide this I suppose. That's the main reason I now use Power Service in every tank of diesel.

Don't understand "chop the throttle". See no need to do this: clutch, shift, and go. Might make some sense with power shuttles, or for those that don't clutch or stop. Don't know about those. Have no experience in any of those areas. I just know I never touch the throttle just to shuttle.

 

[DK35vince]

I use my foot throttle all the time for foward/reversing and FEL work and I always will.
There was a design flaw that was causing the pump failures for a year or 2, plain and simple.

 

[mj007]

I also run my DK40se at 2000-2100 for most mowing and 1800-1900 for backhoe or routine FEL work. I use full PTO speed only when mowing thick spring grass or when tilling new areas.

My rationale is simply that the tractor does the work at those speeds without lugging down and I prefer the lower engine volume. I have no idea if it really saves much fuel or engine wear.

Pretty much what I do

 

[CowwFace]

The engines will reach maximum torque below the PTO rated speed (approx 2100rpm). After that, they will reach maximum horsepower at about PTO speed (2500rpm). The torque falls off slightly above the maximum torque rpm as you reach maximum horsepower rpm. Your engine is running most efficiently at maximum torque, which is in the 2100 rpm range. Also, there shouldn't be any need to run above the PTO rating (approx 2500rpm). Extra wear with no gain in horsepower.

For the HST tractors, the hydrostat runs most efficiently at a minimum of 2000 rpms. This allows the system to build to proper charge pressure. So...if you are working a HST, run it between 2000 and 2500 rpm. For shuttle shift or gear tractors, about the same range for maximum torque, or maximum hp.

Hey MI,

Thanks for this info... exactly what I was looking for. I never knew max efficientency was at max torque. I like the sound of this Diesel at any RPM, but with fuel creeping higher may have to take up skateboards?

Thanks again