What is the different betweent BHP and HP?

[denn1s]

I know what the HP is, but the BHP also is a popular way to describe energy of the car, what is the different between those units?

[curtis73]

Auto glossary defines them like this:

BHP: A measurement of horsepower delivered at the engine crankshaft. A peony brake or an engine dynamometer is used to determine brake horsepower

HP: 1.A measurement of mechanical power or the rate at which work is done. 2. A unit of power, 33,000 foot-pounds per minute. One horsepower equals 746 Watts.

What that basically means is... well, Nothing. Brake horsepower is a means of measuring horsepower at a brake. It measures how much braking is required to hold an engine's output at a certain RPM.

Given the vast array of ways to measure HP, much of it is pointless these days. In 1970 we changed from gross HP to SAE net HP. It was an interesting move that meant the 300 hp engine in 1969 was now only worth 200 hp in 1970 even though it was the same engine. Recently we changed from one SAE standard to another and it further dropped some manufacturer's claims while raising a few. The myriad of ways to measure HP combined with manufacturer loopholes, multiplied by the fact that every dyno is different, compounded by the fact that each individual engine can vary by as much as 15 or more hp, further skewed by the fact that manufacturers often change suppliers of parts several times a month with varying results means that your own butt is the best dyno you can have.

If you do all the "conversion" math, a 450 hp muscle car era big block chevy is worth about 280 hp in 2003. I haven't figured out the new conversions for the 2006 SAE standards, but its getting a bit ridiculous. In an effort to make things more standardized, we've confused the results beyond recognition.

[denn1s]

"In an effort to make things more standardized, we've confused the results beyond recognition."

Thats true mate.

I did some reading on the latest Bosch Automotive Handbook, they did not mention the conversion of BHP to HP, can I conversion like 1BHP=1HP? Otherwise, where the BHP amount come from? If we know the BHP of the, how we can know the KW or HP?

[MunG35]

wouldnt bhp be measured on a dyno?

and doesnt rwd have more power loss in the drivetrain assuming the engine is up front?

[jveik]

umm... i always thought bhp was just a fancy way of saying hp. the only difference is that hp can be measured at the crank like bhp is said to be above in a previous post, or can be measured at the wheels, which is called horsepower at the wheels or whatever you feel like calling it lol, an engine with 400 horse at the crank will have considerably less at the wheels... and as to if the loss is less for a front wheel drive, i have no clue, but i would assume it is about the same perhaps

[SaabJohan]

Bhp means braked horsepower. It's not different from other horsepowers, it just state how it is measured; with a dynamometer (brake). It does not state where the power is measured (crank, wheels and so on), just that it is measured with a dyno.

Any other hp figure can for example be estimated, calculated and so on. One of these is ihp, indicated horsepower which was used early on. This horsepower figure is not measured with a dynamomenter, instead the combustion pressure is measured and the power output is then calculated. Since frictionlosses are ignored the ihp rating is slightly higher than the bhp rating.

[Evelgest Images]

Brake horsepower (bhp) is the measure of an engine's horsepower before the loss in power caused by the gearbox, alternator, differential, water pump, and other auxiliary components such as power steering pump, muffled exhaust system, etc.

One boiler horsepower unit, or (BHP), is equal to a boiler thermal output of 33,475 Btu/h (9.811 kW), which is the energy rate needed to evaporate 34.5 lb (15.65 kg) of water at 212 °F (100 °C) in one hour. The unit is not current outside of North America.

Make sure to read if the BHP is upper or lower case to tell what unit they are using.

[Tdubbz1986]

I deal with Air Compressors mostly for my job and biggest reason you want to see BHP is because all the Compressor manufacturers say they have 75hp air compressor for example. That is just a nominal HP class its not the true HP of the machine and most of it confuses the buyer. BHP is used to show the true Power consumption of the machine because you convert BHP for the power usage not the horsepower and those numbers are the true ones you need to differentiate the true efficiencies of the machines in comparison to wipe out all the BS that sales man will try to give you.
In the car world would just show how poor of a design someone may have. In reality the closer the HP is to BHP the more efficient the machine.

[AliSafe]

HP is general term for Horse power. While BHP stands for brake HP. BHP takes into account the efficiency of transmission which is never 100%.