Mongo
ArboristSite Lurker
I know that this has probably been brought up before but just can't find it. What is the difference between bHP and HP? What does the "b" stand for? Is 4.8bHP the same as 4.8HP?
Horsepower?
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SawTroll
Information Collector
Not exactly.
I think the numbers are 1.0 kW = 1.34 bhp = 1.37 hp, or something very close to that.
As the difference is about 2%, it means that the numbers for hp/bhp usually will be .1 hp apart on a saw with about 5 hp.
The pitfall here is that availiable numbers usually are rounded off to just one decimal, and further calculation based on rounded off numbers are a risky sport that sooner or later will give misleading results.
I think the "b" stands for "brake", and that bhp is a unit mainly used in the US.
I think the numbers are 1.0 kW = 1.34 bhp = 1.37 hp, or something very close to that.
As the difference is about 2%, it means that the numbers for hp/bhp usually will be .1 hp apart on a saw with about 5 hp.
The pitfall here is that availiable numbers usually are rounded off to just one decimal, and further calculation based on rounded off numbers are a risky sport that sooner or later will give misleading results.
I think the "b" stands for "brake", and that bhp is a unit mainly used in the US.
And keep in mind that production scatter is at least +/-10% on horsepower. And you normally are left with the honesty of the manufaturers. Only a test on a brake (resulting in bHP) will really tell.
Best regards
Christian
Best regards
Christian
SawTroll
Information Collector
That may be the origin of the expression bhp, but the results can be published in any unit the test lab or marketing people chooses anyway.....Chris11 said:
If that is the case, it has to be an extreme worst case scenario, as the dyno tests performed by KWF/DLG usually are either the same as the "factory" ones, or just .1 kW off (either way). I remember one test report were it was .2 kW off.Chris11 said:
Crofter
Addicted to ArboristSite
At one time it was common to rate an engines power by a formula that only calculated the diameter and number of pistons and the stroke was not even considered. I think it was referred to as advertised horsepower. Brake horsepower was measured on an engines actual torque at a certain rpm. Problem here is unless you know what the operating conditions were at the time, it doesn't tell you what it will produce in real life. Often no air cleaners are used, water pump and fan may not be used and the output is only for a short period of time. Sustained output horsepower with all necessary accessories could be much lower.
Mongo
ArboristSite Lurker
Thanks for the help! I went to Online Conversions and the categories under horsepower were International, Metric, Electric, & Water and I didn't know which one bHP was related to. As it turns out I don't think it would be categorized with any of those. If I remember correctly 1HP is the amount of energy it takes to lift 1 ton, 1 foot in 1 minute (I could be wrong).[I was wrong! Really bad memory!] I've never heard of "brake" HP. It sounds like there would be some inertial forces involved, such as the weight of the fly wheel. Then again, it's probably irrelevant since resistance is resistance whether it is resistance to being moved or it is resistance to being stopped.
Last edited:
musher
ArboristSite Operative
SawTroll said:
According to autorepair.about.com, Brake Horsepower is defined as:
The measure of an engine's horsepower without the loss in power caused by the gearbox, generator, differential, water pump and other auxiliaries. The actual horsepower delivered to the driving wheels is less.
Mongo
ArboristSite Lurker
musher said:
It seems like I've heard British horsepower from some where before because when I first saw bHP I thought that it might stand for that. I don't know why I didn't mention it before. Just scared I guess!
WadePatton
ArboristSite Guru
And that's where you get RWHP. Which is what us folks who've had their animal on a dyno talk about. REAR WHEEL HP. And the HP varies depending on the type of dyno. If a truck puts 473 onto the dyno--it probably has 500 or better at the flywheel--which is how the engine is originally rated.
But here we are mixing 2-strokes with automobiles.
But here we are mixing 2-strokes with automobiles.
Mongo
ArboristSite Lurker
Thanks again for the info guys!
Mongo
ArboristSite Lurker
rivahrat
ArboristSite Operative
hp
A unit of power in the U.S. Customary System, equal to 745.7 watts or 33,000 foot-pounds per minute.
A unit of power in the U.S. Customary System, equal to 745.7 watts or 33,000 foot-pounds per minute.
Mongo
ArboristSite Lurker
bhp = hp
Oh! So, bhp is the exact same thing as hp. Hmmm!
http://www.sizes.com/units/horsepower_british.htm
rivahrat said:
Oh! So, bhp is the exact same thing as hp. Hmmm!
http://www.sizes.com/units/horsepower_british.htm
bhp is brake horsepower, or horsepower measured using a water or air brake dynomometer. As SawTroll already mentioned, it varies slightly from hp. Unless this is a physics lesson, or something similar, I would simply ensure I convert all of them to the same units to compare them, rather than worrying about the trivial details of the differences.
