Discussion
Twincam16 said:
When (and why) did people start using this abbreviation?
It's short for 'pferdenstark', which is German for 'horsepower'.
So what's wrong with 'hp' then?
It's actually a different measurement, the German's have weedy horses compared to ours. Multiply your manly HP figure by 1.01387 to get the PS value for pussy German horsesIt's short for 'pferdenstark', which is German for 'horsepower'.
So what's wrong with 'hp' then?
NiceCupOfTea said:
It's "metric" horsepower isn't it? I seem to remember hp/bhp is a very arcane definition.
I would have thought you would have known the answer quoting them every day in your job?
The cars I test tend to have power measured in bhp when new. This whole 'ps' thing seems to be a fairly new fad.I would have thought you would have known the answer quoting them every day in your job?
Also, Autocar puts horsepower figures up in the back of its mag alongside the manufacturers' 'ps' codes and the numbers seem to be the same. Just writing it in another language doesn't change the definition of what it is (although even that's confusing - an equestrian mate of mine once told me that a horse actually has 4hp as it's something to do with the power put through each leg of the horse - he could have been talking b
ks though).Mr2Mike said:
It's a "metric" horsepower which is defined in "round" SI units which gives a power close to, but not quite the same as, James Watts original imperial definition. This was published as a DIN standard in 1976, so it's been around a fair while.
Yeah, but it was 'DIN hp' and was quoted as such in road tests throughout that transition period, then accepted as just 'hp' or 'bhp'.I do wonder whether this whole 'ps' thing has something to do with manufacturers not wanting to use the word (or letters to the effect of) 'power' in their advertising literature in case it upsets the comically oversensitive types in Brake who'll write to the ASA the minute anyone suggests a car might actually be fun to drive.
wiki said:
PS
This unit (German: Pferdestärke = horse strength) is no longer a statutory unit, but is still commonly used in Europe, South America, Japan and India especially by the automotive and motorcycle industry. It was adopted throughout continental Europe with designations equivalent to the English horsepower, but mathematically different from the British unit.
DIN 66036 defines one horsepower as the power to raise a mass of 75 kilograms against the earth's gravitational force over a distance of one metre in one second; this is equivalent to 735.49875 W. Similar definitions were already common to the time of James Watt.
The PS was adopted by the Deutsches Institut für Normung (DIN) and then by the automotive industry throughout most of Europe, under varying names. In 1992, the PS was rendered obsolete by EEC directives, when it was replaced by the kilowatt as the official power measuring unit. It is still in use for commercial and advertising purposes, in addition to the kW rating, as many customers are still not familiar with the use of kilowatts for engines.
So there you go, according to the EEC it's been obselete for 20 years. No wonder people still use it This unit (German: Pferdestärke = horse strength) is no longer a statutory unit, but is still commonly used in Europe, South America, Japan and India especially by the automotive and motorcycle industry. It was adopted throughout continental Europe with designations equivalent to the English horsepower, but mathematically different from the British unit.
DIN 66036 defines one horsepower as the power to raise a mass of 75 kilograms against the earth's gravitational force over a distance of one metre in one second; this is equivalent to 735.49875 W. Similar definitions were already common to the time of James Watt.
The PS was adopted by the Deutsches Institut für Normung (DIN) and then by the automotive industry throughout most of Europe, under varying names. In 1992, the PS was rendered obsolete by EEC directives, when it was replaced by the kilowatt as the official power measuring unit. It is still in use for commercial and advertising purposes, in addition to the kW rating, as many customers are still not familiar with the use of kilowatts for engines.
Twincam16 said:
I do wonder whether this whole 'ps' thing has something to do with manufacturers not wanting to use the word (or letters to the effect of) 'power' in their advertising literature in case it upsets the comically oversensitive types in Brake who'll write to the ASA the minute anyone suggests a car might actually be fun to drive.
Nah, it's nothing to do with avoiding the word "power" and everything to do with if you use "ps" you get a bigger number for free. 200ps sounds much better than 197bhp.ETA also 200ps is only 147kW. Smaller numbers are bad.
Edited by Captain Muppet on Monday 16th July 13:20
Horsepower is ridiculously inaccurate, I seem to remember it was when mechanized farm equipment first came into use, and it was the measurement of what one normal horse could plough in a certain time. however, it's even inaccurate to animals as they have a range of power, and can produce much more than normal when stressed (the same for people) it was a existing measurement that was sort of bodged to fit cars when they first came out, as they were the current measurement for steam engines...
This might be complete bks though 
This might be complete b
ks though Mr E said:
I always liked the description of "smaller, metric horses"
I quite like the idea of something like a Bentley as having 'sufficient shire horses', a Ferrari as having a comically overstated number of thoroughbred Arabian race-stud stallions, a Mini as having Shetland ponies and a Citroen 2CV to be measured in donkeys.Agrispeed said:
Horsepower is ridiculously inaccurate, I seem to remember it was when mechanized farm equipment first came into use, and it was the measurement of what one normal horse could plough in a certain time. however, it's even inaccurate to animals as they have a range of power, and can produce much more than normal when stressed (the same for people) it was a existing measurement that was sort of bodged to fit cars when they first came out, as they were the current measurement for steam engines...
This might be complete bks though
It does have an accurate definition, that is based on what James Watt estimated one horse to be capable of achieving (sustainably - even humans can top 1hp for short bursts). 1hp is equal to the capability to move a 550lb force at a rate of 1 foot per second (or 225lbs at 2 feet per second, or 1lb at 550ft per second, etc.).This might be complete b
ks though Twincam16 said:
Yeah, but it was 'DIN hp' and was quoted as such in road tests throughout that transition period, then accepted as just 'hp' or 'bhp'.
That's a different thing again. Power ratings were referred to as DIN to differentiate them from the old American SAE standard. The later gave inflated power ratings by testing the engine with none of the normal ancillaries attached to it (alternator, power steering etc.).Gassing Station | General Gassing | Top of Page | What's New | My Stuff