Why run high rpm's with a diesel ?

Redlands

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Kind of a different deal but on my 2019 diesel pickup I recently got the owners manual pretty much said no break in on the engine. It did stress no heavy loads on the automatic transmission until 500 miles minimum. Seems the transmission and / or rear end needed break in time. Wonder if some of the hydrostatic transmission or other types of transmissions on tractors are similar.
 

D2Cat

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PapaJ, probably not specifically spelled out, but it is a family forum content is asked to meet that idea. If you talk that way with your family, and think it is entertaining here, maybe you're at the wrong place.
 

WFM

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I always baby my tractor and hardly ever run up to the 540 mark. I run at 2000 rpms with bush hogging the fields with hay and brush. If I use my chipper I gradually run it up to the 540 mark as I want all the balls the chipper has.
99% of the tractors life has been in M on the shifter. Seldom L or High.
 

skeets

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Is there a forum rule against the word **CENSORED**? I didn't read the sticky's yet. Asking for a friend...
Dude if you have ask a stupid question like that, you might want to head to another forum! Just MHO you understand
 

PapaJ

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Dude if you have ask a stupid question like that, you might want to head to another forum! Just MHO you understand
No, I don't understand. I took it off as soon as it was brought up, and now you are beating a dead horse. I made a mistake, corrected it and moved on. No need for any more comments about it.
 

troverman

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For the manuals, or the math or torque = horsepower at "x" RPM. As someone who has done this for years now, when you need max power, you run the engine as fast as you can. This, in my experience, is what gives the best result.

I've never hurt any of my engines. Used more fuel? Probably, but I don't care.
 

GreensvilleJay

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With any engine, there are TWO 'curves' to consider, one is RPM the other is torque. Higher RPM doesn't equate to more torque.
Hot rodders who 'dyno' there engines get a report with fancy graphs so they can then 'tune' the engine for whatever purpose they need.
Traditionally a long stroke 6 cylinder engine has more torque than a V8. That was proven when I 'upgrade' my CJ-5 and LOST snowplowing capability.
 

troverman

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With any engine, there are TWO 'curves' to consider, one is RPM the other is torque. Higher RPM doesn't equate to more torque.
Hot rodders who 'dyno' there engines get a report with fancy graphs so they can then 'tune' the engine for whatever purpose they need.
Traditionally a long stroke 6 cylinder engine has more torque than a V8. That was proven when I 'upgrade' my CJ-5 and LOST snowplowing capability.
Sure, but high RPM does give you speed. During mowing, turning knives or blades, higher speed will help you get through the thick stuff without bogging as much.
 

GreensvilleJay

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If you're mowing, you set the RPM for the optimum design speed of the blades(that varies depending on type of blade and size), you adjust ground speed based upon the lawn 'details' ( height to cut, wet/dry, hilly/flat )

mind you the cityboy cross the street goes 'flat out' and mows 2 acres in just over 20 minutes........
 

dochsml

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With any engine, there are TWO 'curves' to consider, one is RPM the other is torque. Higher RPM doesn't equate to more torque.
Hot rodders who 'dyno' there engines get a report with fancy graphs so they can then 'tune' the engine for whatever purpose they need.
Traditionally a long stroke 6 cylinder engine has more torque than a V8. That was proven when I 'upgrade' my CJ-5 and LOST snowplowing capability.
This makes me miss my old Jeep Comanche. It had a 4.0L I6 with tractor-LIKE torque. Wasn't there an old VW commercial where they said everyone talks about HP but drives torque?
 

GeoHorn

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AKA balls to the wall.

SDT
Its my belief that “balls to the wall” were not about counterweight-balls of a governor. They were the ball-shaped knobs on throttles...which were shoved fully against the firewall...to obtain maximum power. This is a common aviation term.
 

SDT

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Its my belief that “balls to the wall” were not about counterweight-balls of a governor. They were the ball-shaped knobs on throttles...which were shoved fully against the firewall...to obtain maximum power. This is a common aviation term.
Both.

SDT
 

Smokeless

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I am not surprised the interest and varied opinions about "what RPM speed". When I took ownership of my 3901 I heard many suggested RPMs. All I know is when working my tractor it functions better closer I get to rated rpms (2700). Finish mower obviously optimum at 540 (2500), but loader and HST seem smoother plus fewer regens at higher rpms. Regens typically move the needle to 2700, rated rpms. Never been to full throttle and after two years, have decided to let tractor specs and work at hand dictate. Rear remotes coming soon, cant imagine 3 pt log splitter working optimum below pto speed. Lots of good info here.
 
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GeoHorn

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Both.

SDT
How is a speed-governor related to a “wall” of any kind? ...and especially since most counterweights are NOT ball-shaped?
 

quazz

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My backhoe is almost unusable at high RPMs. I find around 1600 the sweet spot for power and control.
 

PapaJ

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My backhoe is almost unusable at high RPMs. I find around 1600 the sweet spot for power and control.
My backhoe is my back and a shovel. Or a hoe, depending on the job I guess.
 

dochsml

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How is a speed-governor related to a “wall” of any kind? ...and especially since most counterweights are NOT ball-shaped?
It’s called a flyball governor. From James Watt I believe. Modern etymology expands the term balls out for pretty much anything with a throttle.
 

GeoHorn

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It’s called a flyball governor. From James Watt I believe. Modern etymology expands the term balls out for pretty much anything with a throttle.
I understand that concept... What I’m wondering is how “balls to the wall” came to be thought of as anything other than a ball-shaped throttle and a firewall. I don’t see a connection to a governors ball-shaped weights and a “wall”.