[Rmiller]

I don't understand the G curve. Why do the g's drop while hp remains the same? HP does the work, not torque. So if you made 400 ftlbs up to 3000 rpm, barely breaking 220 hp...then you'd accelerate faster than a car revving to 7000rpm making 250 ftlbs from 4k-7k and peaking at 330 hp?

I don't get it. Can you explain?

[CrawfordPerformance.com]

Originally Posted by Rmiller

I don't understand the G curve. Why do the g's drop while hp remains the same? HP does the work, not torque. So if you made 400 ftlbs up to 3000 rpm, barely breaking 220 hp...then you'd accelerate faster than a car revving to 7000rpm making 250 ftlbs from 4k-7k and peaking at 330 hp?

I don't get it. Can you explain?

Horsepower is a derivative of torque, and torque will decrease as the RPM's increase, this is how the horsepower graph is created. As torque decreases with RPM's, the engine needs to work harder to draw more air in to the engine.

Horsepower can be closesly related to air flow into the engine. As the airflow slows to a flat state, the horsepower will level off also. If there no more ait than before you can not make a bigger controlled explosion, if you can not do that you can not make more power. Since the air flow has leveled off the torque to accelerate the car drops off, because the car is not acceleratiing as hard.

Horsepower keeps the momentum of the vehicle moving, but torque is what makes it accelerate faster and harder. That is why torque is directly related to G's.

Think of an airplane right before take off, calm and peaceful, then the initial jolt to get the airplane moving requires a tremendous amount of torque. That feeling in the seat of your pants as the engines power up to propel the airplane forward is torque or G (based on torque and wieght of the object). Of course the torque falls off because the airplane can not keep a steady acceleration increase.

Hope that helps to explain the G's a little bit more. As for your question, yes the car making more torque will accelerate faster (at that moment) BUT which one will win? This is the questions drag racers have been trying to figure out for years...

Cheers,
Bill

[Rmiller]

Originally Posted by Crawford/I-Speed

Horsepower is a derivative of torque, and torque will decrease as the RPM's increase, this is how the horsepower graph is created. As torque decreases with RPM's, the engine needs to work harder to draw more air in to the engine.

Horsepower can be closesly related to air flow into the engine. As the airflow slows to a flat state, the horsepower will level off also. If there no more ait than before you can not make a bigger controlled explosion, if you can not do that you can not make more power. Since the air flow has leveled off the torque to accelerate the car drops off, because the car is not acceleratiing as hard.

Horsepower keeps the momentum of the vehicle moving, but torque is what makes it accelerate faster and harder. That is why torque is directly related to G's.

Think of an airplane right before take off, calm and peaceful, then the initial jolt to get the airplane moving requires a tremendous amount of torque. That feeling in the seat of your pants as the engines power up to propel the airplane forward is torque or G (based on torque and wieght of the object). Of course the torque falls off because the airplane can not keep a steady acceleration increase.

Hope that helps to explain the G's a little bit more. As for your question, yes the car making more torque will accelerate faster (at that moment) BUT which one will win? This is the questions drag racers have been trying to figure out for years...

Cheers,
Bill

That you so much, I can't tell you how many times I've read "How Horsepower Works" on Howstuffworks.com trying to figure this out.

It's still hard to accept that the rpm of max airflow and fuel usage(max horsepower) is not be the rpm that accelerates the car most quickly. Does this have to do with the fact that energy requirements are proportional to the square of the speed, so as you go faster you require more power to sustain the same accelerative force?