12 replies to this topic

[yungdriva]

i kno HP is short for horsepower. but in magazines i sometimes here BHP, or WHP or somthin. what the hell is that ?

[hoopty dx]

bhp is in metric i think or somthing liek that not sure

But WHP is wheel horse power, its how much power you are makeing at the wheels after drivetrain loss.

HP at the crank will be more.

[pmpicci]

Actually, bhp is english (US). Brake Horsepower. It's a "tangible" figure. Metric units are ps. DIN is the european equivalent of bhp (you'll see the BMW rated this way). I'd be willing to bet that a google search will answer your questions better than I.

[petersterncan]

Metric units are NOT 'ps' . 'ps' stands for Pferde Starke... which is literally German for "Horse Strength"... but basically it means horsepower. German horsepower (DIN standard) is measured a little differently from the North American standard (SAE standard). Years ago (1980s and earlier), 100hp DIN was stronger than 100hp SAE. But apparently the SAE standard was tightened up in the 1990s (can't remember where I read it) and now 100hp SAE is stronger than 100hp DIN.

Now about metric, Kilowatts (KW) is the unit of measure for power in the metric system. 100KW is about 134hp SAE.

(note that I live in Canada, but I'm also a Swiss national and I speak/read German)

Peter

Actually, bhp is english (US).  Brake Horsepower.  It's a "tangible" figure.  Metric units are ps.  DIN is the european equivalent of bhp (you'll see the BMW rated this way).  I'd be willing to bet that a google search will answer your questions better than I.

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[pmpicci]

Well, here in the states we call ps the metric equivalent of bhp (as I said, it's a tangible figure). Now, if you want to discuss SI units, then Watts is where it's at. Sorry if I have confused anyone.

(note that I am engineer, and I'm fairly comfortable with my SI units)

[Jack ffr1846]

As an engineer.....have you ever pondered why we term "weight" as pounds or kilograms?

I weigh about 175 pounds...79 kilograms.

When I go to the moon....I'll still measure in at 79 kilograms, but will be significantly lighter than 175 pounds. (don't remember moon's gravitational acceleration....so divide by 32 and multiply by whatever the moon is)

Ok....not enough engineering for you? (yes, I'm one too). While in college and at the bar one day with my room mate, I pondered our cost of beer. $1 cover charge and $0.50 a beer. I figured out that the more beer we drank, the cheaper our per-beer cost. I used the limit of our cost per beer as the number of beers reaches infinity is $0.50. I was really thinking this IN the bar!

I'll stop now

jack

[GIFF]

$0.50 a beer! what bar are you going to. i want directions.

[petersterncan]

You've got me interested so I've done a little Googling (also wanted to verify my own knowledge)...

ps as defined by DIN (which is just a German standards body), is the German (not European) equivalent of bhp. The reason why BMW (and other German car makers) rates the power on their cars as 'ps' is only because the way you say 'Horsepower' in German is 'Pferdestarke'... and the short form of that is ps. And German car makers adhered to German standards.

All European standards are DIN standards, but not all DIN standards are European standards. (http://www.absoluteastronomy.com/encyclopedia/D/DI/DIN2.htm)

And the ps standard is only metric in the sense that they use metres and kilograms instead of feet and pounds to arrive at a number. Europeans only use ps because people are familiar with it. It's no differant than how people Canada still sometimes use feet, hp, US Gallons and Imperial gallons, in spite of us being on the metric system since the late 1970s.

The official European standard for measuring engine power is in Kilowatts (kW).

I found here:
http://www.unc.edu/~...nits/dictM.html

that 1hp SAE is equal to 0.98632 "Metric Horsepower".

The problem with ps is the same as hp... it varies by the country (and sometimes even by the industry) and the point in time you are talking about. Today, ps is the same thing as "Metric Horsepower", but it wasn't always so. See this for a little history:
http://www.sizes.com.../horsepower.htm

If you were buying a BMW in Germany today, you would see power ratings in ps and kW as you can see here:
http://www.bmw.com/g...I_datasheet.pdf

The only thing I couldn't find was references to the saying that 'German ponies are stronger than North American ones'... which I remember reading more than once in the 1980s. Not surprising since there are very few web sites that have info like this from the 1980s... and none would have existed back then.

Does anyone else here have memory of this? Am I remembering things wrong?

Peter

Actually, bhp is english (US).  Brake Horsepower.  It's a "tangible" figure.  Metric units are ps.  DIN is the european equivalent of bhp (you'll see the BMW rated this way).  I'd be willing to bet that a google search will answer your questions better than I.

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[pmpicci]

Actually Jack, you have confused kg (mass) with kgf (force) since you placed "weight" as the type of measurement. There is an english equivalent of mass too. One pound of mass is equal to one pound force on earth, but 1/32 pound force on the moon. Conversely, one kilogram of mass on the earth weighs 1 kilogram force on the earth and 1/32 kilogram force on the moon. However, the mass of the object is still 1 pound or 1 kilogram on the moon.

To relate this to the topic, 1 bhp is not simply 1 horsepower. Bhp is based upon a "true" reading at the flywheel. Hence, why the bhp formula is based on measured torque. PS also uses a tangible output, but it's based on metric units making it a metric measurement. However, watts are just watts and horsepower is just horsepower. They are not tangible numbers since watts are in joules/sec. Joules (physical) are in how far you move a certain amount of mass. I can make way more watts than a horse if I have a big-ass lever or pully. Make a larger flywheel, and you have a higher power motor...except that you don't. That's where bhp and ps come into play since they assume standards for a reasonable comparison.

[car_bum]

off topic but sortof related,
whats the dirrerence between gros vehicle weight and curb weight?
dan

[zakats]

off topic but sortof related,
whats the dirrerence between gros vehicle weight and curb weight?
dan

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nooo not again!
lol the GVW is the weight of the car + a designated amount of gas + (i think) the max amount of passengers at a designated weight = the gross vehicle weight

curb weight... if i remember correctly thats the empty weight ...epmty yet being fully equipt that is

--zak--

[pmpicci]

GVW is the maximum the car can weigh with total passengers, full tank of gas, and max rated cargo load.

Curb Weight is 1/2 tank of gas with one standard (180 lb) driver.

I think that's the proper assumptions.

[zakats]

sounds more like it...