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Horsepower

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ChaoZ

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What's the difference between horsepower and brake horse power (used on Top Gear and Fifth Gear). Does bhp have to do with the power at the wheels or something?
 
wikipedia.org said:
bhp:

Brake horsepower was a term commonly used before the 1970s in the United States, and is still common in the United Kingdom. It indicates the brake, the device for measuring the true power of the engine. Stating power in 'bhp' gives some indication this is a true reading, rather than a calculated or predicted one. However, several manufacturers started to strip their engines of essential ancillaries for the purposes of getting a high horsepower figure to use in marketing the car.

In the United States the term fell into disuse after the American Society of Automotive Engineers (SAE) recommended manufacturers use "hp (SAE)" to indicate the power of the engine, given that particular car's complete engine installation. This may also be stated as "SAE net hp" or simply "net hp". The British market seemed not to need the correction.
Link to article.

Wikipedia answers all! :mrgreen:
 
^ Right. But in laymen's terms, brake horsepower is the amount of power actually at the rear (or front) wheels. Manufacturers often advertise a car as having a certain amount of horsepower (the engine, that is), but that number is measured at the crank (directly off the engine) and becuase of friction and such, the number is lower at the wheels.

For example, the engine in my car develops 160hp, but there's only about 145 at the wheels.
 
japanese cars horsepower is usually measured at the engine... so they usually carry the unit PS... in continental cars horsepower is measured on wheels, therefore they carry the unit of bhp... not sure abt american cars though
 
andyhui01 said:
japanese cars horsepower is usually measured at the engine... so they usually carry the unit PS... in continental cars horsepower is measured on wheels, therefore they carry the unit of bhp... not sure abt american cars though
No, no no no...PS is short for Pferdest?rke (quite literally "horsepower"), which is a different method of measuring engine power, though ends up with very similar results to the SAE measure of engine power. bhp and hp are interchangeable. The difference between PS and bhp/hp is negligible, but not quite interchangeable. A 200 PS engine puts out 197.26 bhp.

I have never, ever seen a manufacturer cite power to the wheels. Not once.
 
isn't PS just german for HP, like in dutch it's PK
 
US use Net Horsepower which is the power to the wheels and about 75% of the Euro BHP.

This is why the HP figures for US sportscars often look low in comparison to their Euro rivals.

Matthew
 
BTW, I heard that some japanese motorbike manufacters messure the amount of hp on the rear wheel on their light motorbikes (125cc). The reason is that a lot of countries have rules saying that 15bhp is maximum for lightweight 125cc motos.

Measuring on the wheel then logically makes it more powerfull. :D
 
qube said:
US use Net Horsepower which is the power to the wheels and about 75% of the Euro BHP.

This is why the HP figures for US sportscars often look low in comparison to their Euro rivals.

Matthew
Yeah right.
Dr. Woo already said it. No car manufacturer uses WHP. British BHP and US hp are SAE based units, SAE net to be exact, and as such they are the same. European & Japanese use DIN hp (or ps) so they, again are the same.
 
Daniel said:
BTW, I heard that some japanese motorbike manufacters messure the amount of hp on the rear wheel on their light motorbikes (125cc). The reason is that a lot of countries have rules saying that 15bhp is maximum for lightweight 125cc motos.

Measuring on the wheel then logically makes it more powerfull. :D
Sounds like the rule that they used to have in Japan (just very recently thrown out, BTW) that the maximum advertised PS figure was to be 280. Honda has disregarded that "unwritten law" with their new V6 figures.
 
i don't know it's realy a maximum of hp, but over here, you can drive a 125cc from the age of 16, if the bike only has 11KW, you can drive it if from 18 if it only has 25KW, and for higher KW, you need to be 21

and Dr. Woo, do you know what car you posted in your avatar? caus if you ask me it's a big POS :?
 
bone said:
i don't know it's realy a maximum of hp, but over here, you can drive a 125cc from the age of 16, if the bike only has 11KW, you can drive it if from 18 if it only has 25KW, and for higher KW, you need to be 21

and Dr. Woo, do you know what car you posted in your avatar? caus if you ask me it's a big POS :?

POS WTF? That's the most beautiful old Porsche ever! 356 baby!
"the bathtub" :p
 
bone said:
and Dr. Woo, do you know what car you posted in your avatar? caus if you ask me it's a big POS :?
:shock: :shock: :shock: :shock: :shock: :shock: :shock: :shock: :shock: :shock: :shock: :shock:

The Porsche 356 Speedster...a POS? Can I get some of what you're smoking?
 
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