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I found a copy of the text from a web page I found whilst on a quest for the meaning of bhp, a year ago. I'd like to know how close this guy comes to being on the money. thx.

"DIN Horsepower, PS (Pferdestärke), or JIS (Metric, German)

Horsepower is a measurement of the engine's ability to perform work. One SAE horse is the ability to lift 33,000 lbs one foot in one minute. One DIN horse is the ability to lift 450000 kg one cm in one minute. For the same power the SAE measurement is thus 98.629% of the metric DIN measurement.
If you see the term bhp, it just means "brake horsepower", which is the actual usable horsepower delivered to the rear wheels of the car. It is so named because a brake is applied to determine how much pressure is needed to stop or absorb the power. bhp could reference either DIN or SAE horsepower.
Power is effectively torque times rpms, so if you keep the same amount of torque and double the revs, you double the effective power. This is why most engines have the highest horsepower rating at higher RPMs. And along those lines, you can have an engine that has lots of horsepower at higher RPMs, but not much energy at lower RPMs where it counts off the line, so often torque ends up being a more interesting measurement than horsepower.
The formulas used are:
SAE = kW * 1.341
DIN = kW * 1.360 "
 

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The SAE acronym returns a couple of phrases but this one makes the most sense:
Society of Automotive Engineers

Same thing with DIN but this looks good:
Deutsches Institut für Normung e.V. (German Institute for Standardization; similar to US ANSI)
 
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