far too often I read where most tractor owners run their machines at below pto recommended speed for loader work on hydro machines. I understand the pto marker and how it is recommended because of max torque. However, I don't understand why people run there machines between 1500 and 2100 rpms for loader work. Why not run them at above pto marker and at full throttle? There is a reason why the factory allows it to run above pto marker right? That would be to take full use of the cycling rate of the hydraulics when using the loader. So what gives? If the excuse is to save life on the motor, I don't think that you really are benefitting yourself because most construction equipment is ran at full rpms such as excavators and dozers to take full use of the machine. Just curious on what some of the reasoning is. thanks
WOT on diesel tractors
- Thread starter FatSlob
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yelbike
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Fuel economy? If i don't need the full power why run it at max rpm.
Sysop
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You buying my fuel? ...and with an open station my Aspirin? ...along with a few years from now, my hearing aides? 
I'm generally fairly close to PTO speed all the time unless just moving it around a bit for changing implements or to park it or whatever. HSTs need fluid pumping to keep them cool, so I generally keep my RPMs up kind of high any time I'm operating the tractor for a work task. Only time I run the engine over the designated PTO RPM mark is when I'm rolling along trying to get someplace in medium range and want a little more speed but stopping to go to high would be a waste of time, and on those occasions I only run it above the PTO mark long enough to get where I'm going and then back it off to PTO or slightly lower... My engine runs 2400RPM for 540PTO, so generally the lowest I'm operating at is the high end of your range; 2100RPM, perhaps dipping to 2000 under load (if they are dipping under load, I give it more juice so the loads aren't affecting it). The highest I've ran it has been 3000 of the 3400RPM red line while traveling.
I personally try to find a balance of where it gets the best performance, remains the coolest, doesn't suck fuel, doesn't blow out my hearing (I really can't imagine going full throttle through a barn cleaning it out with the FEL), and makes my seat time the best possible experience it can be...
I'm generally fairly close to PTO speed all the time unless just moving it around a bit for changing implements or to park it or whatever. HSTs need fluid pumping to keep them cool, so I generally keep my RPMs up kind of high any time I'm operating the tractor for a work task. Only time I run the engine over the designated PTO RPM mark is when I'm rolling along trying to get someplace in medium range and want a little more speed but stopping to go to high would be a waste of time, and on those occasions I only run it above the PTO mark long enough to get where I'm going and then back it off to PTO or slightly lower... My engine runs 2400RPM for 540PTO, so generally the lowest I'm operating at is the high end of your range; 2100RPM, perhaps dipping to 2000 under load (if they are dipping under load, I give it more juice so the loads aren't affecting it). The highest I've ran it has been 3000 of the 3400RPM red line while traveling.
I personally try to find a balance of where it gets the best performance, remains the coolest, doesn't suck fuel, doesn't blow out my hearing (I really can't imagine going full throttle through a barn cleaning it out with the FEL), and makes my seat time the best possible experience it can be...
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Do you run your car full throttle in first gear. Because there is a mark on the tach indicating pto speed does not mean you have to run it there. It is there to show the operator what rpm the pto turns a specified speed.
Scooby074
Super Member
I generally run mine in the upper 1/3 RPMs. To get the most power and hydraulic flow (speed). Overly low RPMs (lugging) is hard on diesels.
There are many owners on here who baby their equipment. Its their right, but sometimes it does more harm than good.
As to hydro noise, get some of these, plus you'll gain a radio! Closest to being in a cab.
There are many owners on here who baby their equipment. Its their right, but sometimes it does more harm than good.
As to hydro noise, get some of these, plus you'll gain a radio! Closest to being in a cab.
ddivinia
Elite Member
How much more fuel does it burn at WOT vs. half throttle?
I know that when I am running my tractor that even though it is at 540 RPM PTO the turbo is always singing. When I put it under load - it does start singing.
When DPF emissions hit the smaller tractors, I bet people start running them harder to clean the DPF.
D.
I know that when I am running my tractor that even though it is at 540 RPM PTO the turbo is always singing. When I put it under load - it does start singing.
When DPF emissions hit the smaller tractors, I bet people start running them harder to clean the DPF.
D.
TomSeller
Super Member
I'm kinda the same way, I run at the 540 marker when running a PTO device, but otherwise I run at what is comfortable for the engine. I don't lug it, but I don't waste fuel either.
Redneck in training
Elite Member
Running at lower speed doesn't necessarily save fuel. Fuel consumption is more or less proportional to load. In fact looking at the engine charts it is usually the PTO speed where the specific fuel consumption [g/kW/Hour] is the lowest. I run my engine at lower than PTO speed to limit noise but rarely at less than 2000 rpm.
Kubota Engine America - Kubota Engine Line Up - Before 2013 here is a Kubota 2013 engine line up.
http://www.kubotaengine.com/assets/documents/15_v1505t_30.pdf here is 1505 turbo
http://www.kubotaengine.com/assets/documents/13_v1505_30.pdf here is 1505 naturally aspirated
Look at the bottom of the chart where the fuel consumption curve is. Naturally aspirated engine has the best fuel consumption at about 2200 rpm while the turbo at about 2000 rpm.
The turbo has about 4% better fuel consumption. Another advantage of the turbos is they are quieter because the turbo removes large portion of exhaust gas energy. In other words the velocity of the exhaust gas downstream of the turbo is much lower than in naturally aspirated engine. That means less exhaust noise.
Turbo is way to go.
Kubota Engine America - Kubota Engine Line Up - Before 2013 here is a Kubota 2013 engine line up.
http://www.kubotaengine.com/assets/documents/15_v1505t_30.pdf here is 1505 turbo
http://www.kubotaengine.com/assets/documents/13_v1505_30.pdf here is 1505 naturally aspirated
Look at the bottom of the chart where the fuel consumption curve is. Naturally aspirated engine has the best fuel consumption at about 2200 rpm while the turbo at about 2000 rpm.
The turbo has about 4% better fuel consumption. Another advantage of the turbos is they are quieter because the turbo removes large portion of exhaust gas energy. In other words the velocity of the exhaust gas downstream of the turbo is much lower than in naturally aspirated engine. That means less exhaust noise.
Turbo is way to go.
RedNeckRacin
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WOT on some machines makes the hydraulics jerky if your not a skilled operator at that particular piece of equipment as well. It even makes good operators look bad too. For my hydro machine i run it right around the PTO marker for the cooling of the trans. MY gear driven deere, gets run at whatever works. If I know I am going to be doing heavy loader work, I usually set the RPM's at around 1500-1800 to prevent stalling and use the foot throttle to bump it up when i hit the pile or need more hydraulic flow for dumping.
Yes I do run my car at full throttle when I have the loader attached to it so I get max cycling rates when I'm tryin to get a truck loaded faster. I know what everything means on the machine. Was asking a question on others reasoning. No need for anyone to get funny. So the census seems to be to save fuel. Fair enough