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BHP vs. KW

Discussion in 'Technical and Troubleshooting Torque' started by Spud Gun, Feb 16, 2005.

  1. As I hail from the Northern hemisphere I speak in terms of BHP. So to sound a bit like Marty McFly, What the hell is a Kilowatt? I hear both BHP and KW's used to explain car and bike power. Would bikers refer to BHP more than KW due to the European influence? Are both types of unit understood by people?

    An explaination of both and a conversion can be seen here:
    http://www.nathankeogh.com/htm/cars/bhpVkw.htm


     
  2. A Watt is the international standard used for measuring power and is an expression of work done in terms of Joules (the standard unit for energy) per second. A kW or Kilowatt is simply 1000 watts. Metric Horsepower (Pferdestärke or PS) was designed by the Germans and is also in use in Japan as it allows them to use a metric unit of measurement that is still understandable by export customers used to imperial measurements ie the United States. This is why bikes (mostly from Japan) are measured in terms of PS but cars are measured by the scietific standard of kWs.
     
  3. I figure that some people use BHP rather than KW because BHP produces a larger number.

    Kind of like using pounds rather than kilo's for weightlifting. Bigger number; looks better. :)
     
  4. a kilowatt is equal to 1.341 horsepower

    or 3415.1790 btu/hour

    or 239.0585 calories/second

    take your pick
     
  5. Also we are all influenced by the US (rightly or wrongly), and they're not going to be metricated no matter what. All aviation uses feet for altitude measurement, not metres, IMO because the US basically rules the skies. (economically, in manufacture, and sheer numbers of craft)

    We're metric so our unit should be kW, but we have no control over what an overseas manufacturer will use and state (BHP, HP, PS, kW, European Swallow Per Coconut) we're way too small a market to try and force the issue.

    JJ
     
  6. It would be cool to refer to the calorific value of a bike, "Just 22000 calories". You could do a 'no carbs' version! How would that work? :wink: But I guess its just what you are used to. Adding PS to the equation makes it worse. Thats 3 different sets of units. I think Brake Horse Power (BHP) sounds more power related, and kilowatts sounds electrical. So would KW be the Aussie adopted unit?
     
  7. So fat is cool? Yeah!!

    Actually it'll be a joule in metric, or kilojoule,

    IIRC joules/calories more relate to the energy value of the fuel, not the output. (which is calories/joules per second)

    ie that pizza has 1 gozillion kilojoules (xxx calories) & that tasteless piece of foam called a rice cracker has got .2 joules

    "FI" for Fuel Injected

    Yup, orfishally the "SI" metric system, kilowatt's, kilometres, kilograms etc etc

    JJ
     
  8. BHP vs KW

    746 watts equals 1 hp.
     
  9. Hmm I quite like the"calories/second" example and thank you for asking :LOL:
     
  10. Re: BHP vs KW

    hmmmmm
    so that means if I get 12 x 60watt light globes (cheapies from Kmart too)
    I have about one horsepower..... :shock: :shock: :p



    hehehe
     
  11. Keep in mind there are different standards for measuring power.

    If you pick up an american car magazine they seem to get better number then seems reasonable.

    I think the taxi racers use american dynos. That why they are claiming 600 hp from an OHV 5l limited to 7500 rpm
     
  12. yep
    and they are sandbagging..as its more like 640hp
    what else can push a 1500kg taxi to 290kmh.... :LOL:
     
  13. but of course a joule/second == a Watt anyway
     
  14. The maths is easy.

    HP into Kw= A X 0.7457

    Kw into HP= A / 0.7457