[kennybobby]

This is silly to think that a bunch of physickists and mathemagicians can't understand the difference between energy and power?

A 3200 lb car accelerates from rest to 60 mph (88 ft/sec).

The "work" or kinetic energy is .5mv^2 = 387,200 lb-ft regardless of how long it takes to get up to that speed.

But power is the time rate of the change in work or energy, dKe/dt.

So 0 to 60 in 5 seconds = 77,440 lb-ft/sec = 140 hp
and 0 to 60 in 20 sec = 19,360 lb-ft/sec = 35 hp.

How much more fuel does it take for your engine to make 140 hp versus 35 hp?

Look at the dyno data--the torque-speed curve and the volumetric efficiency-fuel consumption curve to find the actual number, but it will be at least a factor of 4.

BTW this is why stop and go traffic kills mileage--it takes so much more power to get up to speed than to just maintain a constant speed.

In this case if your mileage gauge normally reads ~40 mpg for the slow acceleration, then it will drop to ~10 mpg for the faster accel.