HP, PS and BHP - This Madness Needs to Stop

Keeping track of the latest car models is a hard job. There's something new to check out or remember every day, as car companies have gotten into the habit of making different flavors of the same thing. Making matters even worse is the fact that the engine horsepower output isn't measured the same way by everybody.
By now, you've all probably noticed that British journalists talk about something called brake horsepower. It's basically almost the same unit as the horsepower measuring unit used in the rest of Europe… but not quite. On smaller engines, the difference is not noticeable, but on anything from a basic sportscar to a hypercar, it's annoyingly visible. For example, the 1,000 PS of a Bugatti Veyron is 986.4 bhp in Britain.

This not only ruins our understanding of a car, but also hampers the manufacturer's marketing efforts. "The first car with 986 bhp" does't have he same ring to it, now does it?!

That's why we often end up using the "PS" metric rating, which comes from Germany and is the same as the Italian "CV" unit used by Ferrari, Lamborghini, Alfa or Maserati. It's become so mainstream that we found the German "PS" in a Japanese press release for the Infiniti Q50 recently, hiding among the kanji.

So what's so bad about having more than one unit for power? For starters, it creates confusion, even among journalists. It's often not clear which unit manufacturers are using in their brochures.  For example, BMW and Audi rate some of their cars according to the PS system in America. So for example, the BMW M6 and Audi RS6 both supposedly come with "560 hp", even though their ratings are "552-hp" if you were to race them against a Corvette Z06, for example. It's the same with Porsche and many other German companies.

MINI, on the other hand, are supposed to be as British as shepherds pie, which of course they're not. So when you buy a Cooper S with a 2-liter turbo making 192 bhp, it actually has the 192 PS (189 bhp if converted) that BMW engineers wanted it to.

But what really grinds my gears is hearing about the "690 horsepower Lamborghini Aventador LP700-4". Because, hey, what's wrong with it having 700 freaking horsepower like Lamborghini says it does right in the name of the car.

In theory, "horsepower" and "brake horsepower" are totally different things. BHP supposedly measures the amount of energy left once other parts like the gearbox, alternator and water pump have all been powered, basically what reaches the ground. That would mean that all cars are tested twice according to two totally different systems, but what actually happens is PS x 0.9864 = a new number for you to struggle with.

In the rare cases where cars are measured twice, things really get confusing. American automakers like to release very precise numbers for performance vehicles because it makes customers believe in "the dyno rating". When Ford measured the Focus ST's 2-liter engine according to the US standard, it got 252-hp (255.5 PS). But European versions get 250 PS. Am I supposed to believe it's suddenly 2% stronger because it's running on Texas crude?

What's the point of complicating things in this manner, other than to keep us busy and confused?

And that's just the tip of the iceberg in my opinion. There's probably an even bigger problem in the volume and weight department. A pound is exactly 0.45 kilograms. Simple, right? Not really. According to the American system, the car's weight is measured with an average driver, fuel in the tank and luggage. Some people say it's a more honest system, but I'm not paying my dealer to buy luggage, fuel and I'm certainly not of average weight.

Luggage capacity? There's a problem there as well, since some SUVs supposedly have 1,000 liters of it without folding the seats. Basically, if you filled the trunk with water, there would be a whole ton of it in there, or 264 US gallon bottles, which is hard to believe.
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About the author: Mihnea Radu
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Mihnea's favorite cars have already been built, the so-called modern classics from the '80s and '90s. He also loves local car culture from all over the world, so don't be surprised to see him getting excited about weird Japanese imports, low-rider VWs out of Germany, replicas from Russia or LS swaps down in Florida.
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