So to add to the chat...my B2620 rear PTO tachometer marker is around 2750 rpm. This means that when I run my tiller at 540 PTO rpm my engine needs to be running in that sweet spot of around 2750 rpm. I have used my tiller quite successfully using what the manual says. Now, for heavier loader and tough backhoe digging I stay around 2500 rpm and so far everything seems to be fine. As others have said, greater engine rpm means quicker HST response so be mindful of that. If I am doing some light still like moving things from the garage to the shed I usually stick around the 2000 rpm range. But, under-revving the engine is certainly not good...
rpm to operate tractor..
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Respectfully, while a spark ignition engine has a throttle plate to regulate power through regulating airflow, compression ignition engines have an unrestricted air induction system. So the term WOT is not applicable. I know that sound like picking flysh** out of pepper, but it is an important distinction for people transitioning from gasser tractors to diesels.Just like he said these motors are designed to operate at WOT. use more RPMs and don't worry lugging these motors will cause a lot more undue wear than running them at a higher RPM. Use enough motor to get the job done,, If your mowing, the like he said 90% of what the tech is reading,, I run mine WOT when mowing, as you play,,,errrr work I mean WORK with her you will find that happy sweet spot for the motor to work, Just don't lug it down,, And oh yeah pictures we love our tractor porn
At a given rpm, the airflow into the diesel engine is virtually constant and the fuel flow regulates the power output. The mode of control for a diesel is to vary the peak cylinder temperature to regulate power while in a spark ignition engine, the peak cylinder temperature is less variable since the range of variation of fuel/ air ratio is much smaller. Instead power is regulated by air regulation. At a given rpm, air flow is a function of throttle plate opening. At a fixed rpm more power means you open the throttle plate more and the carb supplies the proper amount of fuel in the right proportion to the airflow to develop the desired power output. When the throttle is wide open at a fixed rpm, you are at the limiting power for that rpm. The only way to increase power is to increase rpm, i.e. more airflow.
I think it is important for people to understand these things about how tractors operate.
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Interesting thread. How about the break in period, the first 50 hours? The manual says not to go wot. I have been keeping below 2000 and vary rpms when working. I also let it warm up 5 or 10 minutes at start up at idle. Are these procedures acceptable for the 50 hour break in period? B2650HSDC and new to diesels.
I would say that's fine. I tried to baby mine when new and they have served me well.
My opinion but I believe warm up and cool down time is just as important as changing the oil. I put 28,000 hrs on a Cat loader and never had anything done to the engine. It was warmed up every day before use summer or winter and allowed to cool down at least 5 minutes if I had been running it hard.
On my hat if I'm doing loader work I'm around 2200 rpm. If I'm mowing I'm at 2500. Cruising around I tend to keep it around 2500.
I feel a diesel engine will tell you when it is being labored just by the sound. I have found that 2,000 to 2,200 rpm's is just right for the work I put it through. I have never been a fan of WOT on a diesel. Air cooled engines are different in that they require 80 % to 100 % throttle to keep them cool.
A diesel engine has a specific RPM where it generates peak torque... this is usually the most efficient (lest fuel burned per unit of work) RPM to run your engine. This may seem contrary to thinking that lower RPMs use less fuel...but it is true.
Also, your hydraulic system has to work MUCH harder when the engine RPM is lower than specified operating RPM. Without proper RPM, there may be metal-to-metal contact within the hydraulic pump and more heat is generated. (instead of doing real work)
BOTTOM LINE: Run your engine at specified RPM when you are working it hard. It will use LESS fuel and your hydraulic pumps will last much longer.
Some folks may ask "What is the peak-torque RPM".... the answer is to look at the power/torque curve for your engine. It is obvious where the peak-torque is generated.
Also, your hydraulic system has to work MUCH harder when the engine RPM is lower than specified operating RPM. Without proper RPM, there may be metal-to-metal contact within the hydraulic pump and more heat is generated. (instead of doing real work)
BOTTOM LINE: Run your engine at specified RPM when you are working it hard. It will use LESS fuel and your hydraulic pumps will last much longer.
Some folks may ask "What is the peak-torque RPM".... the answer is to look at the power/torque curve for your engine. It is obvious where the peak-torque is generated.
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My hydraulics sound and react terrible under 2200 on my BX25D-1. Use the RPM that feels right. Let the machine do its job.
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