The Difference between BHP and WHP

[Destrukt]

whats the difference between Brake Horse Power and Wheel Horse Power

and when a new car is listed where are they getting their specs from

my mr2 was listed stock 112 Horse Power

eclipses are listed as 140/210 horse power

but i was looking on dsmtuner at someones dyno sheet and his car is listed at 103 whp

i understand that whp is the amount of horse power you are getting to the wheels but what is brake horse power (BHP) as i have always heard it called

and what do new cars list theirs from?

[vanilla gorilla]

The horsepower specs for new cars are usually the power at the motor, so its always higher than the power to the wheels. Not sure what brake horsepower is. I think it is when they put the car on jackstands and take the wheels off, then bolt up these portable dynomometer things to the wheel studs to measure horspower. Not sure though.

[DragonofBC]

bhp is base horsepower if I'm not mistaken. Its the amount of horsepower to the crank. When you throw drivetrain losses in (from the transmission and transfercase if applicable) it lowers the actual horsepower number you are putting to the wheels and thus pavement.

[E-Klips]

Originally Posted by DragonofBC

bhp is base horsepower if I'm not mistaken. Its the amount of horsepower to the crank. When you throw drivetrain losses in (from the transmission and transfercase if applicable) it lowers the actual horsepower number you are putting to the wheels and thus pavement.

Wrong... BHP is Brake Horsepower. Brake horse power is the measure of engine horsepower without the loss in power caused by the drivetrain. BHP the power at the crankshaft that is measured by a prony brake. Its a simple lever with a brake that connects to the crank. When you apply the brake the lever would deflect and power would be shown. Fairly simple.

Prony brakes are rarely used anymore due to the fact that they have engine dynos and computers that can determine power a lot easier.

Hope that helps.

[DragonofBC]

Learn something new every day

[Shpyder]

Originally Posted by E-Klips

BHP is Brake Horsepower. Brake horse power is the measure of engine horsepower without the loss in power caused by the drivetrain. BHP the power at the crankshaft that is measured by a prony brake. Its a simple lever with a brake that connects to the crank. When you apply the brake the lever would deflect and power would be shown. Fairly simple.

Prony brakes are rarely used anymore due to the fact that they have engine dynos and computers that can determine power a lot easier.

Hope that helps.

Right on. Also, I noticed that here in North America, people say "HP at the crank", and in Europe, "BHP" seems to be much more popular.

[Thor06]

I've heard it referred to as base horsepower as well, actually from that British guy that tests basically every perfomance car ever. He drives them and does reviews n' shit, he did the one on the Ariel Atom. Brake or Base HP its still the same thing.

[clipsekid99]

Originally Posted by Thor06

I've heard it referred to as base horsepower as well, actually from that British guy that tests basically every perfomance car ever. He drives them and does reviews n' shit, he did the one on the Ariel Atom. Brake or Base HP its still the same thing.

Top Gear.... great show.

[Destrukt]

well that answers my question.
so the cars that are on the dyno and show say... 600 whp
have around 750-800 bhp?
or Hp at the crank

[E-Klips]

Originally Posted by Destrukt

well that answers my question.
so the cars that are on the dyno and show say... 600 whp
have around 750-800 bhp?
or Hp at the crank

I dont know if I'd go that much. Maybe 700 to the crank. At the max I'd say 725-730 but thats probably pushing it with a 600whp car. There isnt really that much drive train loss. 20% of the power is the most you could lose. I've heard a lot of people say that AWD is anywhere from 15-20% power loss, so you take 20% of 600whp and that equals 720bhp.

[fastcarfan]

i love the american school system and fuzzy math... if we go by your top end estimate of 20% power loss, then 750bhp to 600whp is correct. 750*.2=150, 750-150=600! you did your math backwards by taking 20% of 600 and then adding it to the 600 or simply taking 120% of the 600. while your math is wrong your estimate of 720bhp to 600whp is probably more realistic as it about a 16.75% power loss.

[SilvrEclipse]

Wow a 3 year old thread. Please do not bring back threads this old unless you have something very important to include.

Also welcome to AF.