Quote:
Originally Posted by wolf370z
Let's take a look at this stock dyno chart for a 370z.
So you're saying that where you have the most power is where torque starts falling off and horsepower keeps increasing? I realize that torque isn't the only part of the force that's pushing you down the track. That's my real question... what else contributes to the pulling force (i suppose pushing force if you were in a rear engine vehicle). |
Let's just ignore wind resistance as a factor for the purposes of this discussion.
Acceleration is directly proportionate to power and weight, so it's definitely the only figure you should be concerning yourself with unless you're qualitatively trying to describe a power curve - then torque is useful. Torque is only a factor when you're talking about engine dynamics, engine internals, and drivetrain strength, etc. It is the instantaneous amount of force your engine is able to slam into the crankshaft - with the crankshaft throw acting as a lever - and subsequently to the wheels. Power is what the road sees.
For the purposes of the dyno graph, you're going to maximize the area under the power curve if you shift right at 7500 rpm (or slightly later) and end up dropping down to 5800-5900 rpm where there is more power available than at 5500 rpm, for example. With our power curve, you sacrifice a little bit of power output at the end of your gear for a lot more power and the beginning of the next gear.
Hopefully that helps.