kw / hp / torque?
Thread Starter
Newbie
Joined: Aug 2007
Posts: 24
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2002 C230 K - 05 spec lights
kw / hp / torque?
Just a quick question for you guys:
What car would statistically be faster from 0-100km/h.
Car A - 170kw and 210 nm torque OR
Car B - 145kw and 280 nm torque?
Not taking weight into account, let us assume they weigh in the same, stock standard cars with these specs..
A car needs torque for pulling heavy loads up hills etc, but what exactly makes it fast? KW or torque? Just trying to understand the science behind it all..
Thanks,
What car would statistically be faster from 0-100km/h.
Car A - 170kw and 210 nm torque OR
Car B - 145kw and 280 nm torque?
Not taking weight into account, let us assume they weigh in the same, stock standard cars with these specs..
A car needs torque for pulling heavy loads up hills etc, but what exactly makes it fast? KW or torque? Just trying to understand the science behind it all..
Thanks,
Junior Member
Joined: May 2007
Posts: 32
Likes: 1
From: Near San Diego, CA
2002 C240
In a race from a dig to 100km/h I would expect Car B to have the advantage. In a 400M / ¼-mile drag race though, it's possible they would be fairly evenly matched by the finish line.
Converting to HP and lb/ft for my uncouth American brain, there is 33HP difference favoring Car A - but about 52 lb/ft torque difference favoring Car B. As torque is a function of power and engine speed, I'd expect Car A to be making those numbers at a higher RPM than Car B makes it's numbers. Hence why I feel Car B would take the 0-60 sprint, but that Car A might tie it up in a standard drag race.
But one key variable you didn't mention is if the gearing is the same on each car. If the transmission and final drive ratios are identical for both cars, I guarantee that Car B will be faster 0-100 every time. It has more mechanical advantage. But if Car A has a shorter (numerically higher) final drive ratio it might be exactly as fast or even faster than Car B in the 0-100km/h sprint.
Or do you already know the answer, and this is just a trick question to trip us up...?
Converting to HP and lb/ft for my uncouth American brain, there is 33HP difference favoring Car A - but about 52 lb/ft torque difference favoring Car B. As torque is a function of power and engine speed, I'd expect Car A to be making those numbers at a higher RPM than Car B makes it's numbers. Hence why I feel Car B would take the 0-60 sprint, but that Car A might tie it up in a standard drag race.
But one key variable you didn't mention is if the gearing is the same on each car. If the transmission and final drive ratios are identical for both cars, I guarantee that Car B will be faster 0-100 every time. It has more mechanical advantage. But if Car A has a shorter (numerically higher) final drive ratio it might be exactly as fast or even faster than Car B in the 0-100km/h sprint.
Or do you already know the answer, and this is just a trick question to trip us up...?
Last edited by Firemane; Nov 6, 2007 at 11:09 AM.
