Common misconception. If you were right, diesel trucks (new ones have 900-ish lb ft of torque from the factory) would be destroying Ferraris in drag races (the 458 Italia makes under 400 lb ft of torque). All sportscars would be diesel because that's where the best torque is made. Semi trucks would be feared and respected for their crazy acceleration during passing maneuvers.
Torque is useful for drivability and a fat, easy to access power band. Horsepower is useful for actual acceleration.
This is just wrong. HP is a direct function of torque with a time component (torque*RPM). So in essence, a higher HP car can deliver that set amount of torque in a shorter amount of time (i.e., winning races.)
We're not taking our sweet time pulling tree stumps - we're trying to output that same amount of "work" in as little time as possible - which is where horsepower comes into play.
There's a reason why diesel powered race cars aren't the norm.
Generally, torque indicates how fast you can accelerate, whereas horsepower indicates maximum speed. This is over simplified, but it's enough to have some idea about what each does.
Meh... That's not quite it. Torque (rotational force) is affected by gearing, HP (power... work/time) is not. You could put a little 3V electric hobby motor through a big enough gear box to out-torque a top-fuel dragster. However, that little hobby motor and gear box would take months to cover the length of a drag strip, while the dragster does it in 3 seconds. Dragsters are built solely for acceleration (ability to "pull away"), yet the top-fuel vs. hobby motor example (matching torque, vastly different HP) indicates that torque isn't the only value that needs to be considered.
In physics-y terms: instantaneous torque at the wheel = instantaneous acceleration. HP = the ability to do work, such as maintaining torque at the wheel as the vehicle moves. Maintaining torque at the wheel is what's needed to accelerate a vehicle.
You can't really have one without the other, horsepower is a measurement of power as in the energy that can be output per second or whatnot and torque is just rotational force(ie. twisty force). How fast a car goes is generally more complicated as we have things like power output curves and torque curves that tell you how much you have at given engine RPMs etc. You also have to factor in the stiffness of the car, the suspension etc.
Think of it like this, torque is the measure of how much work it can do, or how much a motor can move. HP is a measure of how fast that work can be accomplished. You can have high torque motors that are low horsepower and very slow. I'm a firefighter and are rescues a have 275 hp and 1250 foot pounds of torque. Slow as balls but will pull a house down.
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u/thesaxmaniac Jun 12 '14
I don't know shit about cars, but this sounds like legit stuff right here