Horsepower  can become a tricky business however, with values measured in different  ways. BHP (brake horsepower) refers to the equipment needed to test the  engines for their power outputs, with a large drum with a water brake  within it measuring the braking force once the engine is spinning at a  desired rate. Over in the US, this is measured with only some ancillary  components attached to the powertrain, missing things like the power  steering pump which would lead to a lack of parasitic losses if in  place. Therefore higher ‘HP’ figures are calculated in the US than the  BHP figures calculated in Europe where every component is kept in place.
PS:-1PS = 0.986hp
PS  stands for pferdestärke which translates simply as horsepower, but it  has had some metric tweaking to try and bring good old HP forward into  the 21st Century. This metric horsepower has been adopted throughout  Europe as the new standard for power measurement and will probably make  its way fully into the UK psyche in the not too distant future.
The  official engineering standard for metric horsepower is the amount of  power needed to lift a 75kg of mass one metre vertically in one second,  which – once the conversions from imperial to metric are applied –  equates to a 1.4 per cent higher figure than the old imperial units.  Manufacturers will often pick and choose between PS and HP depending on  whatever figure seems more rounded and presentable. Although I’ve always  just seen PS as ‘horsepower plus a few’.