HP vs Weight and Acceleration Question

[DavidRam]

I'm trying to understand this:

If identically equiped trucks, one weighing 6000lbs and the other weighing 10% more at 6600lbs, both having 400hp.

What difference should they have say in 0-60, or 1/4 mile times???

Or how much more hp would the 6600lb truck need to equal the acceleration of the 6000lb truck???

 

[Brakelate]

Well, if memory serves me well, then this is the difference in power to weight ratios.

0-60 mph and 1/4 mile times would need a baseline for me to start with.


The 6,000 lbs truck with 400 hp has a power to weight ratio of 15:1.

Meaning every Horsepower has to pull 15 lbs.

The 6,600 lbs truck with 400 hp would have ratio of 16.5:1

To get the 6,600 lbs truck to match the lighter truck's ratio, it would need an extra 40 Hp in theory.

Torque is what really makes things move, so that is a more complex calculation. As is the 0-60 and 1/4 times, as it is all fluid, in regards to how the same truck with the heavier load, more Hp, or both will react. Meaning under load, the heavier truck might hold gears for longer periods and all sorts of variables in the "real world" that will shift those performance numbers around.

From my experience, in watching these things play out at the track in real time, you are probably looking at 4/10ths longer to 60 mph and about 7.5 Tenths of a second in a full quarter mile which would roughly be up in the high 17 second range for a 1/4 mile run.

Hope that helps.

Some REAL math whiz can come in and tear into my numbers, but it's a ballpark figure to start with.

 

[DavidRam]

That is awesome man, thank you! You are quite the math whiz yourself!