luismatta

My E63s shows me the data on KW, how can I change this to HP?

78degrees

kW is the SI unit used for power, no reason to show anything else.

simarddominic

+1
I can have HP and lb/ft units for the power and torque on the right screen but I a have KW and nm on the left screen and I'm unable to change it.

WillyBolly

You won't believe how many times I've come across this question on the forums. I didn't know the answer to it myself until I came across this one poweretty.com website. Here you can find information about absolutely every car, including BMW. I found a table with the dynamics of BMW from generation to generation. Each series of this car is considered in detail. You can find a table that shows data in both HP and kW. Everything is done very simply and clearly. I was able to choose a suitable, powerful car with the help of this graph. It shows the car's power and simplifies your choice.

ygmn

1kW = 1.3410 Hp.
or
1hp = 0.7457 kW = 745.7Watt

I rounded the conversion terms as my HP engineering calc goes a bit more places after the decimal.

Little Extra Geeky Engineering info (all 8 years of college paying off now! LOL)
HP = TORQ(ft-lbs) * RPM / 5252

Dynos measure TORQ & RPM and calculate HP.

E634Me

HP is a marketing term invented by James Watt way back when. It was based on rotational torque and how much force a horse could generate in an hour by turning a mill wheel. Specifically, he determined that the horse could turn a 12 ft radius mill wheel 144 times in an hour while pulling with 180 pounds of force. The value was revised after Watt and others evaluated more data on a typical horse's performance. So as noted above, HP is actually a numerical calculation derived from torque. Because the HP is not rooted to physical constants, it was replaced in the 1970s in Europe by the kilowatt (kW) as the official power measuring unit. There are still a number of different horsepower definitions floating around, which is why we see 603 HP for the E63s in the US and 612 PS given for the European version. Both cars produce the same power in watts.

The SI (International System of Units) unit for power is the watt, named in honor of James Watt and is based on fundamental physical units. Specifically, 1 W = 1 kg x m^2 x s^-3.

I could go on, but this doesn't solve the question of how to display which unit on the dash . . .

E634Me

For grins I checked to see what horsepower units Mathcad had built in.

The horsepower type, the Mathcad unit, the power in watts (to five decimal places):
Horsepower, hp = 745.69987 W
Boiler horsepower, bhp = 9809.5 W
Electric horsepower, ehp = 746 W
Water horsepower, hhp = 746.043 W
UK horsepower, hpUK = 745.7 W
Metric horsepower, mhp = 735.49875 W

Setting the US E63s horsepower to exactly 603, the power is 449.65702 kW (to only five decimal places)
Converting the 449.65702 kW to the other horsepower units I get:
hp = 603
bhp = 45.83893
ehp = 602.7574
hhp = 602.72266
hpUK = 602.9999
mhp = 611.36341

Fun stuff

willypos

In my opinion, all these conversions are easiest to perform with the help of online converters, such as this one https://www.asutpp.com/kw-to-hp.html

E634Me

But not nearly as much fun :-)

There are many online calculators and several of my scientific calculators also have built in converters. But as was mentioned in an earlier post, sometimes it's nice to be able to put those years of engineering education to use and crank the numbers on your own.

That's why I like this channel: https://www.youtube.com/@EngineeringExplained

He takes the time to work through the math and show why things work out the way they do, including units along the way, in a pretty easy to follow process for the layperson.

YYC53

I think they're easiest to convert by finding the setting in the car. As much as I giggle at the Merican use of cubits, US gallons and useless units....I still use HP.