# Torque vs HP and WHP vs BHP!!!!!



## MCHNHED (Dec 22, 2002)

hey guys,

I have come across a little dilemma while i try to explain all of this car shit to my friends who don't know too much about mechanics and stuff. I can not effectively explain the difference between TORQUE and HORSEPOWER or WHEEL HP and BRAKE HP!!! can anyone out there who is a physics head please help me out???


----------



## bahearn (Jul 15, 2002)

Torque is power is force x distance (ft-lb). It's what turns the crankshaft.
Horsepower is work is torque x time (torque x rpm ÷ 5252).

Brake horsepower is measured on an engine dyno and is taken at the flywheel or transmission output shaft (depending upon standard). Originally, dyno used a water brake to apply resistance against which the engined worked. *SAE Gross HP* was measured on engine in which ALL accessories were driven by external power source, even the water pump, and engine was hand-fitted to provide largest capacity using off-the-shelf components (blue-printing). This standard provided a rather theoretical figure and was used until about 1970. *SAE Net HP* required actual production engine with all accessories and transmission attached. This gave a much more realistic horsepower figure the car buyer could actually expect as it takes into account the power needed to spin the accessories. Still taken on an engine stand though dyno is now typically an eddy-current dyno, though water brakes are still in use.

Wheel horsepower is measured at the wheel, naturally, on a chassis dyno. This accounts for driveline losses that SAE Net test doesn't see.


----------



## 88 Pulsar SE (Mar 25, 2003)

To be super basic: Torque is the ability to do work & HP is the speed at which the work can be performed.........I know not exactly right, but may help explain it to a non mechanical person.


----------



## bahearn (Jul 15, 2002)

Or, torque is acceleration while horsepower is speed.


----------



## JustMe (Jan 24, 2003)

basically yes...but horsepower is not real it is a number derived through a formula based on torque 

A wise engine builder once said "Horsepower sells motors, torque wins races"


----------



## sethwas (Apr 30, 2002)

Hmm,
Torque is the ability to twist. More torque more ability to twist, independant of RPM.
Horsepower on the otherhand is very dependant on RPM. So low torque high rpm can give similar HP readings to high torque low RPM.
This is why in a compact car you have to downshift to get speed, you need the higher RPM to get more power, whereas in a big ole 8cyl you already have the torque down low so you don't need to shift.

Seth


----------



## Scissors (Mar 24, 2003)

Torque you feel, HP you talk about. To a layman, that's the biggest difference.


----------



## mrfox (Mar 11, 2003)

the less torque there is, the higher the engine must be revved to produce an certain amount of power.

torquey engines are easier to drive, harder to stall, less shifting needed, and perfect for lazy ass drivers!


----------

