My only point here is that HP is what correlates with acceleration. I can derive all the equations if you guys are interested. Harleyís make massive torque and we all know how slow they are. They do this by making HP at low RPMís, which as our equations show, results in high torque.
Many gas turbine (jet engine) vehicles make high HP but at high (think 55,000RPM) engine speeds. This results in very little torque at that speed but also gives crazy acceleration. If the engine makes power down low, it may also have high torque.
To put this another way, if I put an accelerometer in my car and accelerate on flat ground, I can estimate my horsepower directly. To get torque, I need to know what RPM Iím at. This is why I say that HP is what matters because it directly correlates with acceleration. Not torque.
I would like to see a dyno curve that illustrates what you mean. Torque is force and force produces horsepower. Horsepower is an expression of work which is torque over a period of time. You can flip the formula anyway you want but it's still the same.
Torque is not force. Torque is the cross product of your force and distance vectors.
I think we are getting lost here. A dyno can only measure HP of the engine, not torque without some engine speed measurement. It may do this by measuring how much something is torqued (such as a water brake). Then, once you tell the dyno what the engine speed is (typically by putting a sensor on the spark plug cable) you can resolve engine torque. It must know the engine speed to calculate engine torque. This is for a chassis dyno of course.
I'll use this analogy: MotoGP engines. Most produce in the neighborhood of 250bhp. But the only way to use it is with electronic controls that keep torque output steady enough for the tire not to spin and as the machine gains traction going from full lean to full upright. The electronics only feed in as much torque as the tire can put to the pavement (ideally) and a flat 250 bhp with no electronic mitigation in a 335-lb. motorcycle would be nigh onto uncontrollable. So horsepower, while important, is definitely not the only thing that counts. you can have as much bhp as you can get, but putting it to use is dependent upon torque at the tire/pavement interface.
I saw a perfect example at Indy MotoGP a few years ago; The Honda Team, Marc Marquez and Dani Pedrosa came out of the infield and onto the fast part of the track neck-and-neck. As Marquez dove to the inside, his footpeg snagged Pedrosa's rear wheel speed sensor wire and disconnected it. When they emerged onto the front straight, they hammered the throttles and Pedrosa was immediately spit off in a spectacular highside that he was lucky to escape unscathed from. Both had the same horsepower, but the only thing that mattered was the torque put to pavement.
This kind of confuses the argument a bit. We are talking torque at the engine (as a measure of how good the engine is) not torque at the rear wheel. For what you are talking about, you are correct. Torque at the rear wheel is what decides many things (such as going into a wheelie, burning out, etc.). This isnít as relevant because it has to go through the transmission which typically increases torque in lower gears at the rear wheel. I can use a transmission to develop almost any torque at the rear wheel.
Torque is science. Horsepower is scientology.
Haha sure. Horsepower is power which is energy over time. It can be just as easily measured in Watts, as in a 75W lightbulb. There is ~745 Watts per HP if I remember correctly.