Mowing High Lift Blades take much more power?

[RuT]

I have a TC29D with 72" 914a side discharge. I have always been unhappy with the way it mows using the standard blades. I purchase the high lift blades from Messicks NH, non mulching, and the mowing quality is much much better. I suggest high lifts for anyone concerned about the quality of cut. My mower constantly left a trail of uncut grass on the left side unless the deck was spotlessly clean underneath.

My question is...would one suspect the high lift blades to place more power requirements on the engine? I used to mowed at the recommended RPM with no loss of RPM using the standard blades. This season, I lose 400 - 500 rpms when heading up hills with the mower on. On flat ground it is fine. All air, fuel and oil filters are new. Could something else cause the power loss?

 

[zzvyb6]

I would be surprized if a 25hp diesel tractor would drop that much in rpm with a set of high lift blades. They DO use more power (can tell by the sound and the fury) to essentially pull more material per second thru the deck at the same ground speed. I use them occasionally on my 72" deck on a JD F935 front mower and can barely tell the power loss or rpm change. Mine is a 23hp diesel.

Check the tire pressures to make sure they are not low. I'd also check the underside of the deck to make sure its not caked with mud which would interfere with the higher air flow. These blades tend to give me more deck crud.

You can always put the other blades back on as see if you get the rpms back. Even change them out one at a time to see if you improve incrementally.

 

[Jerry/MT]

I have a TC29D with 72" 914a side discharge. I have always been unhappy with the way it mows using the standard blades. I purchase the high lift blades from Messicks NH, non mulching, and the mowing quality is much much better. I suggest high lifts for anyone concerned about the quality of cut. My mower constantly left a trail of uncut grass on the left side unless the deck was spotlessly clean underneath.

My question is...would one suspect the high lift blades to place more power requirements on the engine? I used to mowed at the recommended RPM with no loss of RPM using the standard blades. This season, I lose 400 - 500 rpms when heading up hills with the mower on. On flat ground it is fine. All air, fuel and oil filters are new. Could something else cause the power loss?

The high lift mower blades that I'm famililiar with have more camber (curvature of the blade chord line) at the tip and they should take more power to run them at any engine/pto speed. Running on the flat, you have set the engine speed and the while you can't measure the fuel flow rate, it's higher than the standard blades and so is the power out put of the engine.

You probably notice it more on the hills because of the incremental power it takes to climb up the hill is added to the higher power requirement of the blades and the governor speed droop (the change in rpm with a change in load) is greater than if you were using the standard blades and climbing the hill.
I think what you are seeing is normal for the change to high lift blades.