low RPM

[Denwa]

more power? HMM... more flow.. but pressure it develops should be the same at idle vs throttle... at least if it is a positive displacement pump..

soundguy

Yah, more flow, that's what I meant. More flow reduces the effort of each cc of fluid to achieve a desired result and therefore smooths things out.

I know I can dig better, push harder, go up steeper hills w/o stalling if I up the RPM.
D

 

[pat32rf]

I know I can dig better, push harder, go up steeper hills w/o stalling if I up the RPM.
D[/QUOTE]

You can do all of those things because your engine is making more power at higher RPM. If I an just diddling along my driveway or a smooth trail then I am running at about 1500rpm with my foot halfway down. If I come to a hill, I either let up my foot or increase the rpm. I figure as long as the engine is putting out more power than I am calling for, then things are fine. Been that way for over 4000hrs....
Mowing or blowing calls for full PTO speed however...So does heavy loader work. Backhoe is probably about 2000rpm and the logsplitter runs at 1200rpm so I can hear the radio.

 

[Soundguy]

Yah, more flow, that's what I meant. More flow reduces the effort of each cc of fluid to achieve a desired result and therefore smooths things out.

I know I can dig better, push harder, go up steeper hills w/o stalling if I up the RPM.
D

that's more of a power available from the engine issue than the 'power' of the hyd pump, as the other poster stated.

soundguy

 

[Don87]

Like many, I run my engine appropriate to the task.

I usually don't go below 1500. I usually run my PTO equipment at or close to 540, but for years ran our 60's model Case and cutter at what "felt right". It is still running strong and never has had any repairs.

I am no different than many in that maybe I tend to over think some of this stuff. When I was younger and did this for a living so to speak, I operated more by feel than anything else.

I do accept there are parameters beyond which we should not go, but they may be broader than some of us think.

I also do the same.

While mowing, there are places in my yard that is 'thin grass'(thus I can throttle down). Other places are very heavy grass, throttling up is an absolute necessity.

When using the FEL...........light chores only need a lower throttle to function to work without bogging the engine, while digging may require full throttle on occassion.............just depends on the task at hand.

Ya kinda get a feel for it after a little while, the machine will 'talk to ya'..........you learn the dialect

 

[General Lee]

According to the folks at my Kubota dealer, diesel engines, particularly the smaller ones, AND including the hydraulic pumping system, are much happier
running at higher RPM than at lower. The faster the engine/pump is operating, within red line of course, the less strain on the systems.

Fuel consumption will be a bit more, but which is less expensive, fuel or repairs? Same reason a car/truck engine is happier if one downshifts when going up steep grades.

Me, I keep the RPM up when using the implements..

Regards,
Dennis (WA)

Its funny you mention "within red line". On my Kubota L4400, red line or max rpm is PTO speed. When my mower is attached I can't throttle the tractor any higher than the PTO mark on the tach.

 

[Don87]

Its funny you mention "within red line". On my Kubota L4400, red line or max rpm is PTO speed. When my mower is attached I can't throttle the tractor any higher than the PTO mark on the tach.

But as was explained in an earlier post.............it is possible to 'overtach' a gear drive machine while going downhill with a load on.

EDIT: I worked at a garage before driving truck, and I live in the mountains. Seemed like every week, a truck driver would let his truck come off the hills on I68..........twisted the impeller off those old Cummins engines every time(over-running the tach).

Had a few blown engines also.

Ain't nothing like going to tow one in and seeing a half mile oil trail on the interstate because the driver 'overtached' and threw a rod through the block, or pan, or had the 'accessory drive' explode.

Saw one driver.........overtached...........accessory drive exploded........threw pieces into the car that was passing him. totalled the car, and shut down the interstate till they got the oil spill cleaned up.

I fishtailed thru that one with my big truck. Butthole puckered the entire time.

I'm the one that called 911