Has horsepower changed?

[infire]

It seems to me that a tractor rated at 180hp in the 90's has more power than a 200hp today, anybody else notice this? I am looking to replace my 9180 rated at 375hp but not sure what size to go with, can't get by with any less hp on my ripper & yet I don't need alot more hp or wieght packing the ground. Suggestions would be appreciated.

[4wd · Accepted solution]

yah, I have noticed that too. Seems as though the slick paper ads talk about flywheel hp which no one can ever get out of a tractor. In the old days draw bar hp was published on all tractors. Don't even see that any more except in the Nebraska tractor tests. Maybe Neb is where we all are going to have to look to find out the truth in advertised hp. These marketing ads sure are worthless.

[Sid15]

I feel the opposite.  Most new tractors w/ electronic fuel injection will generate a lot more hp beyond the rated hp.   What has probably changed is that same hp is trying to push more weight, which I guess would support your argument. 

[siloguy]

If both today's tractor and the old ones are rated the same PTO or drawbar hp, they should do about the same amount of work. Most of the newer engines have a broader torque curve so they may do a bit more with different loads. It is true that many of the newer tractors tell you engine hp, which cannot be compared to the old PTO hp because there is a lot of drag between the engine and the pto or wheels. It is common to lose 50-100 hp of parasitic loss. So, buyer beware..

[infire]

OK, so I looked up a STX430 on the Neb. tests & on drawbar hp. the highest it ever got was 351hp. An STX430 is advertised as a 430hp tractor. Then I checked a Stieger 485 and tops at drawbar on it was about 441hp. So your comment about buyer beware is dead on if not an understatement. Seems as though a guy better demo first to make sure it will handle your work load. Thanks for the Neb. suggestion, I guess if I wasn't so dense I would have thought of that.

[siloguy]

But STX430 sounds much more manly than a more appropriate name like SUX351!

[Nebrfarmr]

Nebraska USED to have a law that said that they could randomly pull a tractor out of any dealer's lot within the state, test the tractor, and that tractor had to have the advertised horsepower.  Any less, and they had to pay a fine, submit several tractors for testing, or risk not being able to sell the tractor in the state.  This meant that the manufacturers would 'turn up' the tractors a bit (or rate them a little low) so that if there was one in the lot that didn't quite run as well as the others, it would still make 'rated' HP.  Remember, each and every tractor had to make rated HP, or better.  For example, I run an old IH 5088.  They were 'rated' at 136 HP, but have been told by an old-timer in the dealership that they averaged close to 150, and a really good-running one might squeak out 160HP. 

Since then, the law has changed so that they test several tractors, and as long as they 'average' their rated HP, it is OK, so you might have 2 tractors rated at 200 HP, one that puts out 185, and one that puts out 215 (due to manufacturing variances) and they both would be fine.

However, I do feel that now with computer controlled injection systems, the tractors are a lot more consistant.  In the old days of mechanical pumps, there was a lot more variance from machine to machine.

[kiwiana]

I think the only fair way is to compare maximum rated PTO horsepower - at the rated RPM - usually 2000,  or 2200. This eliminates tire and weight comparisons which vary according to farmers' wishes. It also takes into account all electrical, AC, and hydraulic power losses. But now I notice a new variation - maximum PTO horsepower. This seems to occur after the motor is lugged down to 1800 revs or so, and it's quite a bit higher the the maximum horsepower at rated revs (sometimes by 10 or 15).

Kiwiana

[notiller9350]

Good One!!!

[dapper7]

any cih 7120 owners out there? just wondering what most ran for hp?just bought one, fresh overhaul,new turbo and injectors. was told 170 hp. sounds a bit stout to me. thanks