BigEddy
Gold Member
- Joined
- Sep 6, 2002
- Messages
- 268
- Location
- Eastern Ontario
- Tractor
- JD 855, 322, AMT626 plus whatever my son dragged home this month
I think I know what's going on.
The Hydro pump(s) on the tractor are always running, flowing fluid around the circuit. The HP consumed by the pump(s) depends on the GPM and the pressure. GPM varies with engine speed and is not changing, but the pressure changes with the load.
When you are going straight, there is no load on the hydraulics - therefore no pressure, and the HP demands are essentially nil - just the friction losses.
When you turn at the end of the row - pushing the steering cylinder drives the pressure up, increasing the load on the pump and therefore the engine. If you turn to the stop, the relief opens at the max pressure and therefore max HP drain. Assuming 2000 psi and 4 GPM, that would be over 5HP load on the engine. If the 4010 has 14HP PTO, holding the steering against the stops would reduce blade HP over 1/3rd, and that would definitely affect performance.
This can be avoided by more gradual turns, or backing off the steering before the stop is hit.
I know my 322 with PS will bog on a tight turn IF I turn all the way to the stops and hold there, but won't if the stops aren't hit.
That's my best guess as to what's going on.
The Hydro pump(s) on the tractor are always running, flowing fluid around the circuit. The HP consumed by the pump(s) depends on the GPM and the pressure. GPM varies with engine speed and is not changing, but the pressure changes with the load.
When you are going straight, there is no load on the hydraulics - therefore no pressure, and the HP demands are essentially nil - just the friction losses.
When you turn at the end of the row - pushing the steering cylinder drives the pressure up, increasing the load on the pump and therefore the engine. If you turn to the stop, the relief opens at the max pressure and therefore max HP drain. Assuming 2000 psi and 4 GPM, that would be over 5HP load on the engine. If the 4010 has 14HP PTO, holding the steering against the stops would reduce blade HP over 1/3rd, and that would definitely affect performance.
This can be avoided by more gradual turns, or backing off the steering before the stop is hit.
I know my 322 with PS will bog on a tight turn IF I turn all the way to the stops and hold there, but won't if the stops aren't hit.
That's my best guess as to what's going on.