Enough HP???

[dgl24087]

Nebraska Tractor Test rated the TN70 closer to 60 PTO HP. http://tractortestlab.unl.edu/NewH/NHtn70D.PDF

 

[Doc_Bob]

Actually.. isn't the engine hp closer to 66? In any case.. an open question to -all- here.. why 66 eng hp, and only 57 pto..
Soundguy

PTO HP on TN70A is as you state, 57HP.
3ph will lift 3950 pounds.
I cannot explain the large difference between engine and PTO power.
Bob

 

[Tom_Veatch]

Are both Engine and PTO HP ratings at the same engine RPM? If not, that could account for some of the difference. What HP is the engine developing at the RPM needed to spin the PTO at 540?

 

[greg_g]

...that's a whopping 13.63% of eng hp drop.. My other ford / NH diesels have 5.25% and 5.5% drop

Your Ford/NH numbers sound optimistic at best. I've always used " the 14% rule " for geared tractors. When testbed numbers are not available from the manufacturer
1. subtract 14% from engine hp to get PTO hp
2. subtract another 14% from PTO hp to get drawbar hp

13.63% is close enough to 14 for me

//greg//

 

[Fredex]

Diff. between engine hp & pto hp: Diff. between rpm at 540 pto and max engine hp as already stated. Also, maybe diff. between gross engine hp and net engine hp. Gross often measured sans fan, water pump, alternator, hydraulic pump,etc. Don't know whether tractor mfgr's use gross or net.

 

[Doc_Bob]

Don't know whether tractor mfgr's use gross or net.

The 70 HP for New Holland TN70A engine is gross.
Bob

 

[schmism]

The 70 HP for New Holland TN70A engine is gross.
Bob

so then we have net engine hp in the 66 hp range

then the "step down" to 540 PTO hp....

either way you want to slice the pie... i still say go for it (if its a good deal)

 

[flusher]

Actually.. isn't the engine hp closer to 66? In any case.. an open question to -all- here.. why 66 eng hp, and only 57 pto.. That's a 9hp drop... I'm used to seeing half that on some other tractors... etc That's some pretty massive loss between the flywheel and the pto shaft... that's a whopping 13.63% of eng hp drop.. My other ford / NH diesels have 5.25% and 5.5% drop based on eng and pto hp listings. They are also gear units.. Anyone else have observations on this?

Soundguy

My neighbor has a NH3010 that's supposed to have a 55-hp engine per the NH brochure, yet TractorData.com shows it has 42-hp at the PTO. That's a heck of a lot of loss (nearly 24%) in the transmission and PTO gears. Makes me wonder if these numbers are correct.

 

[Soundguy]

A TN70A has 70 engine HP per the NH repair manual.
Bob

I was just going off a few online resources, however, I don't remember if i saw an 'A' listed.. just the tn 70. Perhaps it's an updated model. ( or the online #'s are wrong... wouldn't be the first time.. )

Soundguy

 

[Soundguy]

Nebraska Tractor Test rated the TN70 closer to 60 PTO HP. http://tractortestlab.unl.edu/NewH/NHtn70D.PDF

Again.. that was a tn70.. not a tn70a.. same thing I missed earlier. After digging into a dealers website.. apparently the different models do have a few different #'s.

here's what NH says about the tn70a:

70 gross eng hp
57 pto hp
2300rpm rated speed

Soundguy

It looks like many of the online sources are quoting Net eng hp, and Pto hp.. while NH and NH ref materials are quoting Gross eng hp, and pto hp.. etc.

Soundguy