HP lies
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=29051
Printed Date: 26 Jun 2024 at 1:27am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: HP lies
Posted By: Eldon (WA)
Subject: HP lies
Date Posted: 13 Apr 2011 at 8:59am
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Saw a tractor for sale yesterday, a Ford 7700 listed at 100 HP. The seller said he needed a bigger tractor to pull his disc. I emailed and said that was because the tractor is only rated at 68 hp at the drawbar and that is the number that counts. He said the dealer told him it was 100 hp. Seems everyone is using engine HP now, a figure that the Nebraska Tractor tests don't even mention. I think it is kinda misleading....what do you guys think? ------------- ALLIS EXPRESS! This year: |
Replies:
Posted By: KGood
Date Posted: 13 Apr 2011 at 9:13am
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Wasn't CIH using that method recently then changed back. There numbers for tractor model size where using engine horse instead of drawbar horse and misleading people. Again that is just hearsay to me and I shure don't follow CIH's tractors or equipment. To answer your question no I don't think thats right. |
Posted By: Hurst
Date Posted: 13 Apr 2011 at 9:20am
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I have always seen tractors from NH and most other companies advertised by PTO horsepower. A 7700 should be north of 85 PTO hp on paper, but those turbo 4 bangers will put out north of 100 hp at the PTO easily with just a turn of the screw and do it reliably for years and years. There's a local welding shop owner that does highway batwing mowing and runs ford 7710s and 7610s and had at least 1 of the 7710s running 115 PTO hp on the dyno after turning up the pump and never had any problems. Hurst ------------- 1979 Allis Chalmers 7000 5800 Hours |
Posted By: Russ-neia
Date Posted: 13 Apr 2011 at 9:50am
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Another of my many beef's with AGCO. Dropped the orange tractors which were the only ones on the market where the model number indicated the PTO hp. Not aware of anyone now whose numbering has any correlation to PTO or DB hp - or kilowatts - for that matter. ------------- The innovators offer what others will imitate. |
Posted By: Gerald J.
Date Posted: 13 Apr 2011 at 10:22am
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That's why there are Nebraska Tractor Tests. Even then the tractor vendor gets to pick the tractor to be tested, its not randomly chosen from a dealer's lot so it might be tweaked for the test. Gerald J. |
Posted By: wkpoor
Date Posted: 13 Apr 2011 at 11:25am
| Not sure when mfg started doing this but it is pure marketing and marketing like bigger #s. When comparing tractors many don't realize what #s they are comparing. My 1995 JD5400 is a 60hp tractor at the drawbar but toady they are calling it a 75hp I think. And that Engine hp not drawbar. 100hp engine and only 68DB seems quite a spread. |
Posted By: 427435
Date Posted: 13 Apr 2011 at 3:20pm
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The engine Hp thing got started with Versatile and then Steiger. They had no PTO's and just advertised the engine Hp of the engines they were using. That's the reason the 4w-305 was called what it was--------305 engine hp.
------------- Mark B10 Allis, 917 Allis, 7116 Simplicity, 7790 Simplicity Diesel, GTH-L Simplicity Ignorance is curable-----stupidity is not. |
Posted By: allis restorer
Date Posted: 13 Apr 2011 at 3:25pm
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At the farm we have a ford 7700 and a 7710 and the 7700 is turned up to 95HP and could be turned up even more yet, and the 7710 is only at the origanal 85HP because that just got a new motor, them 4 cylinder fords you can get alot of power out of them. Steve ------------- Go orange or Go home!! |
Posted By: JohnCO
Date Posted: 13 Apr 2011 at 4:04pm
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Didn't Nebraska stop doing tractor testing? It's too bad because at least they leveled the playing field some.
------------- "If at first you don't succeed, get a bigger hammer" Allis Express participant |
Posted By: Gerald J.
Date Posted: 13 Apr 2011 at 5:23pm
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Last I looked they were still testing. Gerald J. |
Posted By: DanD
Date Posted: 13 Apr 2011 at 5:29pm
http://tractortestlab.unl.edu/ - http://tractortestlab.unl.edu/
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JohnCO wrote:Posted By: wkpoor
Date Posted: 13 Apr 2011 at 5:49pm
| I'm guessing but since few under 100hp tractors actually farm anymore few get Nebraska tested. Most, like mine, are just utility tractors and I will say most of the work it does is off the PTO so engine HP is more important to me. Still even engine HPs get manipulated in the marketing quagmar. |
Posted By: Gerald J.
Date Posted: 13 Apr 2011 at 6:12pm
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I found several 40 -45 hp tractor tests at that link. Gerald J. |
Posted By: Byron WC in SW Wi
Date Posted: 14 Apr 2011 at 7:19am
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Drawbar hp used to be the most important thing when farmers went from horses to tractors. They didn't have equipment than ran off the PTO or even belt yet so they wanted to know how much it could pull compared to their horses. Then they moved up to belts and PTO equipment so you got belt hp because you wanted to know if it could blow silage up your thirty foot silo. Now, anything up to 200 hp needs to be able to run a PTO and the PTO equipment will have minimum PTO hp required so that is what is most commonly used. I don't really care how much engine hp it has I want to know drawbar and PTO. The only time I look at engine hp is when I care about efficiency and want to know how much engine hp their loosing with parasitic loss. |
Posted By: Gerald J.
Date Posted: 14 Apr 2011 at 9:21am
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Nearly always there's more horsepower available at the belt or PTO shaft than at the drawbar because there are fewer gears to the belt or PTO shaft and that power isn't having to move the tractor with the rolling friction of the tires. Gerald J. |
Posted By: DaveKamp
Date Posted: 14 Apr 2011 at 10:23pm
| Well, and the immediate limiting factor of drawbar horsepower is the ratio of applied weight over driven wheels and diameter of driven wheels... vs applied weight over undriven... and the diameter of undriven wheels. If a 100hp tractor is unballasted, and on small diameter tires, it won't make drawbar horsepower... but a 50hp tractor, properly ballasted, will make full use of what's coming out of the crankshaft. |
Posted By: 7060
Date Posted: 14 Apr 2011 at 10:28pm
| Our New Holland TG285 is 285 engine hp but 240 pto. All the TG series is that way. What really gets me is trying to figure out Massey Fergusons numbers. |
Posted By: Gerald J.
Date Posted: 15 Apr 2011 at 12:45am
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When Nebraska tests a tractor they put plenty weights on the drive wheels. The stack sticks out at least a couple feet on each wheel. Gerald J. |
Posted By: 427435
Date Posted: 15 Apr 2011 at 9:48am
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The weights that go on a Nebraska test tractor are determined by the manufacturer. The biggest reason for the drop between PTO and drawbar hp is the last "gear mesh"---------the one between the tire and the cement. Optimum drawbar hp usually comes with the slippage between 6-7% (for 2wd tractors). That slippage is lost power.
------------- Mark B10 Allis, 917 Allis, 7116 Simplicity, 7790 Simplicity Diesel, GTH-L Simplicity Ignorance is curable-----stupidity is not. |
Posted By: DaveKamp
Date Posted: 16 Apr 2011 at 3:44pm
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Yes, the tractors are tested as-brung, and the tests I've read, indicate the ballast included, and where. The Wismer-Luth analysis identifies agricultural tractive effort prediction as I noted above, and Harold (Luth) developed the slip/horsepower/tractive effort ratio using empirical data as the BASIS (not the other way around). Harold recently retired from Deere & Co, did this one long ago... not long after he started as an ag engineer with D&C. Really neat guy, I spent many evenings sitting on the beaches of river islands with him and his family. |