1 brake horse power

bobbarley · 1 Oct 2011 at 20:46

Does anyone know what the definition of one brake horsepower is? Is it literally one "standard" horse, or some set power ratio?

PhillyDee · 1 Oct 2011 at 20:47

Well, yes. It is a standardised unit. It was based on what one horse could pull.

PMKeates · 1 Oct 2011 at 20:47

In imperial mechanical terms it's 33,000 ft-lb/minute, in metric terms it's 0.73549875 kW.

All info here:

http://en.wikipedia.org/wiki/Horsepower#Current_definitions

Most publications by auto manufacturers use the metric figure.

bobbarley · 1 Oct 2011 at 20:49

Wonder why some companies are switching to PS instead?

PMKeates · 1 Oct 2011 at 20:52

bobbarley said:
Wonder why some companies are switching to PS instead?

PS is metric horsepower aka pferdestarke the literal German for "horse strength". Most auto makers have published PS figures for years and labelled them horsepower.

Check this out:

http://www.bmw.co.uk/bmwuk/pricesan...wuk@gas-NQ==,00.html?tab=technicalSpec&isPGA=

Under engine:

Max output (kW/hp/rpm) 230/313/4400

That's 313 metric hp aka PS. It would be 308 or 309 imperial/mechanical hp.

PhillyDee · 1 Oct 2011 at 20:56

Because its slightly higher. And therefore looks better.

PMKeates · 1 Oct 2011 at 20:56

PhillyDee said:
Because its slightly higher. And therefore looks better.

Which is not the case at all, and as I said, most manufacturers have been using metric hp/PS for years without you knowing.

PMKeates · 1 Oct 2011 at 21:01

As the ultimate highlight of how these terms are used willy nilly, the Morgan website:

http://www.morgan-motor.co.uk/carpages/supersports/supersports.html

ENGINE

4799CC V8

MAX POWER

270kw (367/bhp)

The reality is that 270 kW is 367 PS, and they've just pasted the horsepower specs from BMW and labelled it "bhp".

From the 4/4: http://www.morgan-motor.co.uk/carpages/44/44.html

ENGINE
1595cc 4 cylinder

MAX POWER
82 kw (1 10 bhp) @ 6000 rpm

82 kW is 111 PS and 110 mechanical HP, so they've chosen the HP here. The engine is produced in Brazil by Ford.

Dogbreath · 1 Oct 2011 at 21:28

PMKeates said:
In imperial mechanical terms it's 33,000 ft-lb/minute, in metric terms it's 0.73549875 kW.

One imperial brake horse power (which is the unit widely used for automtive engine power) is equivalent to about 0.746 kW.

PMKeates · 1 Oct 2011 at 22:01

Dogbreath said:
One imperial brake horse power (which is the unit widely used for automtive engine power) is equivalent to about 0.746 kW.

It is not at all widely used for automotive engine power. It is less common than metric HP and kW. It has wide use in the US but very limited use elsewhere.

DRZ · 1 Oct 2011 at 22:05

Dogbreath said:
One imperial brake horse power (which is the unit widely used for automtive engine power) is equivalent to about 0.746 kW.

I'm sure you're convinced you are correct but in this instance I am going to go with the guy that spends all day every day advising companies like BMW about these sorts of figures

bobbarley · 1 Oct 2011 at 22:33

PMKeates said:
In imperial mechanical terms it's 33,000 ft-lb/minute, in metric terms it's 0.73549875 kW.

All info here:

http://en.wikipedia.org/wiki/Horsepower#Current_definitions

Most publications by auto manufacturers use the metric figure.

What model Beemer have you got? Looks lovely!

PMKeates · 1 Oct 2011 at 22:41

The one in my sig? It was a 330i Individual that I had from 2006 until 2009

http://mkeates.com/beams/ for more pics!

Django x2 · 1 Oct 2011 at 22:43

You should note, brake horsepower and horsepower (as used in the US) are two very different things.

PMKeates · 1 Oct 2011 at 22:55

Lucero said:
You should note, brake horsepower and horsepower (as used in the US) are two very different things.

The thing is, in reality they aren't. They are two terms used to mean exactly the same thing i.e. horsepower.

Dr Who · 1 Oct 2011 at 22:56

PMKeates said:
The thing is, in reality they aren't. They are two terms used to mean exactly the same thing i.e. horsepower.

And both are a theoretical calculated figure which is meaningless

PMKeates · 1 Oct 2011 at 23:00

Dr Who said:
And both are a theoretical calculated figure which is meaningless

Why is it theoretical?

mjt · 1 Oct 2011 at 23:38

PMKeates said:
The one in my sig? It was a 330i Individual that I had from 2006 until 2009

http://mkeates.com/beams/ for more pics!

Lacks interior shots!

PMKeates · 1 Oct 2011 at 23:47

mjt said:
Lacks interior shots!

Troo

http://mkeates.com/elacole/beams/frontinterior.jpg

MikeHiow · 1 Oct 2011 at 23:47

Dr Who said:
And both are a theoretical calculated figure which is meaningless

LOL What?

Are you getting confused with opinions of drive on dynos providing ATF figures?