Why run high rpm's with a diesel ?

[mikester]

If you want max power for PTO driven implements, use wide open throttle. If you are doing loader work, or some other non-PTO function, than use less throttle. The advantages of less throttle are many: less fuel consumed, less noise, less jerky / sensitive controls.

Ive read plenty of OEM warnings NOT to exceed the implement rated PTO speed i.e. 540RPM, I dont think running the engine at WOT is good advice. Set the engine speed to give you 540RPM at the PTO.

Equipment manuals generally warn against over speeding AND lugging the engine.

 

[GeoHorn]

WOT usually results in 540 PTO RPM.... that’s the way most gov’s are set up.

 

[skeets]

As it was explained to me, the motor developed different amounts of HP and torque at different RPMs. So operating the motor where the highest torque and HP is in the curve is the ideal sweet spot for the implement you are using, and with the "K" that is WOT where HP and torque cross. Now for putting around the yard you do not need WOT just what you need to get from here to there. Lugging a motor down any motor will cause undo wear on parts and things brake. Simple do what the book says to do, and its all good, or do what you think is right and see what happens!

 

[Tornado]

Ive been following this thread with some interest. In the first 50 hours of my tractor, which is only just passed, I never ran the tractor at full RPM, not even once hardly, as the manual states not to do so during the break in period. The L2501 maxes out at what 2400rpm or so. The 540PTO is at around 2100 rpm. I havent used a PTO implement a single time on my L2501 its been all loader and box blade and disc harrow work. Pushing tree tops into burn piles, moving logs, clearing woods in prep for grass planting and yard expansion. Most all of this work I did at around ~1900 - 2000 RPM I dont know if thats good or bad. I was trying to mind the break in period, and thist just felt and sounded like a good place to be on the tractor. Had plenty of power, but wasn't super loud from the engine. Being a new tractor owner this is one topic Ive tired to educate myself on - but like most things regarding tractors everyone has different opinions. WOT for rotary cutters vs. just setting it at the 540 mark - as is starting to be debated here. I really wish there wasnt all this big difference in advice from tractor owners, as I find new owners often just end up more confused as to what is right and just throw it all out and do their own thing. You can find "tractor experts" on youtube with popular channels, and years of experience giving exact opposite advice on these types of issues. I find it unhelpful and unfortunate.

Ive tried to just follow the manual, mixed with my own common sense. The manual essentially says to match your RPM with your work. Ive tried to roughly follow this rule. Even now that my break in period is over, I still feel odd working at wide open throttle. I was discing the other day, and pulling a good load, and this is likely whre wide open throttle would be good, but I still didnt run wide open. I ran it around 2100-2200rpm. Maxed out 2400 RPM the engine just is loud and sounds like its racing. Im so used to gas engines that its hard to reprogram myself. To me the racing engine just roaring nonstop sounds like a gas engine that needs to go into a higher gear. There is the inward feeling that you are overstressing the engine - though with diesel I understand this is NOT the case. Its someting I will continue to try and work on and be better about. My primary goal with my tractor is to do things right and get the most life out of it.

 

[SidecarFlip]

WOT usually results in 540 PTO RPM.... that’s the way most gov’s are set up.

Incorrect, at least with a diesel. PTO rpm is based on maximum torque rise, not wide open throttle (maximum governed rpm). Maximum governed rpm is maximum horsepower, not torque and torque is what dies the work, not observed horsepower.

Both my M9's are governed at 2550. Pto speed is is 2100. I've never run either at maximum governed rpm, ever and most times not at recommended pto rpm either. They make so much power at PTO rpm, I don't have much need to run at 2100 unless I'm round bailing, where I need that shaft speed to build tight bales.

With lower power requirement (pto implements like fertilizer spreaders, grain legs and rakes, I run the 1000 pto shaft (21 spline) with a 21-6 adapter and run even less rpm because the torque required to run those implements is even less. Lower operating rpm (engine), means longer powerplant lifetime.

The newer engine, emission compliant ones, from what I ascertain, need to be run at maximum governed speed to insure the emissions hardware operates correctly. Seems very counter productive to me as diesels were designed originally to operate at a lower rpm with a higher torque rise than a gas motor. Lower operating rpm equates to longer life and more efficiency (fuel usage) as well.

I bet Rudy is rolling over in his grave....

 

[powersrp]

Sounds like your doing fine, gradually work the rpms up, i dont think i have ever needed to max throttle my tractor, except for regen, also correct, max rpm does not always equal 540 on the pto, im around 2150 running a 3 pt 60” finish mower.


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[quazz]

For me a lot of it is feel and most of us can tell if the engine is lugging or the RPMs are too high for comfort. I simply try to stay in the zone where the engine feels like it is running perfectly and this varies by the job I am doing. I don't think you can write rules for every different situation, general guidelines on RPMs might be fine but common sense and a feel for your engines is best .

 

[RyanG]

I've been wondering the same thing with my BX2380. I have the 60mmm and use it for loader work and cutting my lawn. As in the manual, below 50hrs don't run at max RPM... The only problem is 540pto on mine is max RPM (3500rpm).

I've been running mine at 3Krpm while mowing. But just yesterday I ran it at WOT 3500RPM (540pto range), which did help a bit with how well it cut the grass. for about 30min. Hopfully I didn't hurt anything (at about 28hours).

The issue I see is anyone with a BX2380 (I'm guessing all BX's) and running PTO equipment, will never actually be able to use the PTO correctly under 50hours without the risk of hurting the engine?

I know with my B3030 WOT was above 540PTO so I never actually ran it that high anyway.

 

[PapaJ]

I've been wondering the same thing with my BX2380. I have the 60mmm and use it for loader work and cutting my lawn. As in the manual, below 50hrs don't run at max RPM... The only problem is 540pto on mine is max RPM (3500rpm).

I've been running mine at 3Krpm while mowing. But just yesterday I ran it at WOT 3500RPM (540pto range), which did help a bit with how well it cut the grass. for about 30min. Hopfully I didn't hurt anything (at about 28hours).

The issue I see is anyone with a BX2380 (I'm guessing all BX's) and running PTO equipment, will never actually be able to use the PTO correctly under 50hours without the risk of hurting the engine?

I know with my B3030 WOT was above 540PTO so I never actually ran it that high anyway.

When the guy delivered mine, and went over it, he said, when you cut grass, throw this here lever all the way up. That would be WOT. A break in was never mentioned to me by him or the sales guy. Of course, as a prior diesel mechanic, and generally semi-intelligent person, I am aware that new engines nearly all have a break in period. The most important thing is to vary RPM's though. Running WOT is not going to hurt a new diesel engine, unless that is the only status it is run at, and then you have a 50/50 shot. The reason is to vary the cross hatching on the cylinder walls so there is not just 1 pattern for oil/fuel to flow inside the cylinder before combustion. I will continue to mow at 540 RPM's, and drive around and FEL stuff at less than that.

 

[RyanG]

When the guy delivered mine, and went over it, he said, when you cut grass, throw this here lever all the way up. That would be WOT. A break in was never mentioned to me by him or the sales guy. Of course, as a prior diesel mechanic, and generally semi-intelligent person, I am aware that new engines nearly all have a break in period. The most important thing is to vary RPM's though. Running WOT is not going to hurt a new diesel engine, unless that is the only status it is run at, and then you have a 50/50 shot. The reason is to vary the cross hatching on the cylinder walls so there is not just 1 pattern for oil/fuel to flow inside the cylinder before combustion. I will continue to mow at 540 RPM's, and drive around and FEL stuff at less than that.

Agreed, thats typically what I've always heard and done. And have been doing so far. I'll run anywhere from 2000-2800 changing it every so often while doing FEL work and moving etc. Thankfully the first 20+ hours were FEL work so it was under 2800rpm and I was able to keep changing it. Just recently I started cutting grass and used 3000-3100 rpm for that untill the last time (Yesterday), but I think I'll run it closer to WOT from now on since it did make a pretty good difference in cut quality.

(It's kinda like buying a push mower at HD and saying for the first year only run it half throttle to break it in even though it won't work right)

 

[troverman]

Ive read plenty of OEM warnings NOT to exceed the implement rated PTO speed i.e. 540RPM, I dont think running the engine at WOT is good advice. Set the engine speed to give you 540RPM at the PTO.

Equipment manuals generally warn against over speeding AND lugging the engine.

You generally can't rev much past PTO speed anyway. With mowing, if you set your throttle at 540, going from a lighter to a heavy patch will bog the engine down. I'd rather be running a hundred or two RPM's higher than 540 and have a little leeway for the thick stuff. I've done it this way for years and never hurt a thing.

When the guy delivered mine, and went over it, he said, when you cut grass, throw this here lever all the way up. That would be WOT. A break in was never mentioned to me by him or the sales guy. Of course, as a prior diesel mechanic, and generally semi-intelligent person, I am aware that new engines nearly all have a break in period. The most important thing is to vary RPM's though. Running WOT is not going to hurt a new diesel engine, unless that is the only status it is run at, and then you have a 50/50 shot. The reason is to vary the cross hatching on the cylinder walls so there is not just 1 pattern for oil/fuel to flow inside the cylinder before combustion. I will continue to mow at 540 RPM's, and drive around and FEL stuff at less than that.

I agree, but keep in mind Deere front end loaders now run at a constant RPM all the time.

 

[Freeheeler]

I just throttle according to what I'm doing. If it bogs a bit I crank it up a bit. Really doesn't matter since this diesel will be running long after I get relegated to the scrap heap.

 

[GeoHorn]

Incorrect, at least with a diesel. PTO rpm is based on maximum torque rise, not wide open throttle (maximum governed rpm). Maximum governed rpm is maximum horsepower, not torque and torque is what dies the work, not observed horsepower....
:

Flip, you and I both are/were speaking in generalities, so iTs a bit incorrect to say the other is incorrect.

Example: the generality you make above is absolutely at odds with my Owners Manual, which states MY M4700 engine (F2803-ELA) max RPM is 2600 and is where they also rate the max PTO power. The specifications page on MY M4700 states that 540 PTO RPM is achieved at 2300 RPM...which happens to be virtually WOT.... only 300 RPM below the engine rated max RPM (which by the way, is never achieved due to the governor.)

Further, you comment regarding the HP vs Torque differs considerably from what my specification page states, ... as it states max RPM is 2600 but max torque is achieved at 1600. (And thats not a misprint either.)

Im looking at YOUR M9000 specifications page and it differs from what you posted. The one Im looking at states YOUR engine (V3300-TIE) max RPM is 2600 and that is where they rate its HorsePower. And its max torque is at 1400-1600 and YOUR M9000 540 PTO RPM is achieved at 2205 RPM (as opposed to the 2100 you posted... so you are either running below PTO speed or the spec page is wrong.) But either way its pretty close GENERALLY to WOT.

So... my previous comment that PTO 540 RPM is at WOT for most tractors.... was made in the generic sense, as that is where very nearly most governors begin to kick in. (OK, well not FULLY WOT... but just a smidgen below WOT.)

 

[dochsml]

When did WFO become WOT? When I was learning to operate machines, all the old farts would tell me not to go around running it WFO all the time or I'd blow up the engine. WOT makes it sound legitimate or normal.

 

[SDT]

When did WFO become WOT? When I was learning to operate machines, all the old farts would tell me not to go around running it WFO all the time or I'd blow up the engine. WOT makes it sound legitimate or normal.

Bingo, Dochsml.

Much can be explained by considering who owns (and maintains) the equipment rather than who operates it.

Much more to this topic but I'll bide my time.

SDT

 

[Henro]

When did WFO become WOT? When I was learning to operate machines, all the old farts would tell me not to go around running it WFO all the time or I'd blow up the engine. WOT makes it sound legitimate or normal.

Having worked many years in steel mills, I think I can relate to WFO, but not completely sure. W probably means wide, and O probably means open. Does the F in WFO mean what it would in a steel mill?

 

[dochsml]

Having worked many years in steel mills, I think I can relate to WFO, but not completely sure. W probably means wide, and O probably means open. Does the F in WFO mean what it would in a steel mill?

Seeing as I grew up also north of Pittsburgh in a little town called Butler (before Armco Steel became Armco Kawasaki Steel), I'm pretty sure it does!

 

[GeoHorn]

WFO Weather Forecast Office
WFO Workforce Optimization (software)
WFO Wirtschaftsförderung Osnabrück Gmbh
WFO Waste Frying Oil
WFO Western Field Ornithologists
WFO Washington Field Office
WFO Work for Others (USACE)
WFO World Fashion Organization
WFO World Federation of Orthodontists
WFO Work from Office
WFO Wood Fired Oven
WFO World Future Organization (Los Angeles, CA; est. 2009)
WFO Wide Full Open
WFO World Food Organisation
WFO Western FJR Owners (Yamaha motorcycles)
WFO Westminster Fire Office (UK)
WFO World Football Organization (soccer)
WFO Workforce Management Optimization
WFO Worldwide Freezing Order (formerly Mareva Injunction)
WFO Wide Freakin' Open (polite form)
WFO Wall Furniture Outlet
WFO Wild Florida Online
WFO Waste Facilities Operations
WFO White Folk Only
WFO Wing Field Order
WFO Weights Fully Out (old steam engine term, denoting maximum engine speed) I.E> GOVERNED SPEED
WFO Wound Flat Out
WFO Women for Ocala

 

[dochsml]

WFO Weather Forecast Office
WFO Workforce Optimization (software)
WFO Wirtschaftsförderung Osnabrück Gmbh
WFO Waste Frying Oil
WFO Western Field Ornithologists
WFO Washington Field Office
WFO Work for Others (USACE)
WFO World Fashion Organization
WFO World Federation of Orthodontists
WFO Work from Office
WFO Wood Fired Oven
WFO World Future Organization (Los Angeles, CA; est. 2009)
WFO Wide Full Open
WFO World Food Organisation
WFO Western FJR Owners (Yamaha motorcycles)
WFO Westminster Fire Office (UK)
WFO World Football Organization (soccer)
WFO Workforce Management Optimization
WFO Worldwide Freezing Order (formerly Mareva Injunction)
WFO Wide Freakin' Open (polite form)
WFO Wall Furniture Outlet
WFO Wild Florida Online
WFO Waste Facilities Operations
WFO White Folk Only
WFO Wing Field Order
WFO Weights Fully Out (old steam engine term, denoting maximum engine speed) I.E> GOVERNED SPEED
WFO Wound Flat Out
WFO Women for Ocala

But the weights were ball shaped usually, so they would just say Balls Out.

 

[PapaJ]

But the weights were ball shaped usually, so they would just say Balls Out.

Is there a forum rule against the word **CENSORED**? I didn't read the sticky's yet. Asking for a friend...