Herbaliser:
fritz:
Herbaliser:

Sorry, but for improved accelration you need torque only. HP influence only max speed.

 

Sorry but this simply isn't true. For 200+ acceleration you only need HP. Torque is almost irrelevant. It shouldn't take much digging to find the physics behind that. 

Assume you have two cars with exactly the same weight, aerodynamics and maximum horsepower, but one has an engine tuned for maximum power with less regard for low-down torque and the other has a relatively flat torque curve up to its max power revs. (This is what you would typically get if the first car has a larger displacement naturally aspirated engine and the latter a smaller displacement turbocharged engine).
If you matched the acceleration of those cars against each other, the high torque engined car would wipe the floor with the low torque variant. 
As someone else already said, your max power output figure is more significant for defining a car's top speed.

You are talking about cars with the same HP. In that case, the one with more torque will win especially at lower speed acceleration. What I am trying to say is that it is impossible for a 580 hp to get to 300km/h as fast a 650 hp car no matter what the torque curve is. Even if there is a wide 1000NM plateau it will only help the low to mid speed acceleration.  

So for Autobahn racing I would take a 650hp engine over 580hp engine no matter the torque (given the rest is equal). That's why the 911 Turbo S is not much faster than the 458 Italia (if at all) at 200+ even though there is a dramatic torque difference.

You cannot talk about acceleration in general. 0-200 is one story with torque, weight, traction playing big role, 200-300 is another where it's all about top-end power (HP), aerodynamics and gearing.   

The fallacy in the sentence in bold is that the rest is not equal in that comparison. The 650hp engine would also have higher torque than the 580hp engine at engine speeds below the max power speed if the higher powered car has faster acceleration. (Assuming again that weights and aerodynamics are equal). 
Power figures are derived directly from the torque readings measured on a dynamometer at given engine speeds. 
You should take your own advice and look into the physics behind it. 
 


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fritz