Ferrari Mailing List: Re: Torque and horsepower

[Doug & Terri (dnt]

You shift 400 RPM past max torque and are geared so the next shift is 400 rpm under max torque.  In a perfect race car and track.

DOUG

 

From: Ferrari [mailto:ferrari-bounces+dnt=dock.net [at] ferrarilist.com] On Behalf Of Rick Lindsay
Sent: Friday, March 6, 2015 6:39 AM
To: DOUG
Cc: The FerrariList
Subject: [Ferrari] Torque and horsepower

 

A few words, and a chewy question.

 

Always confusing terms, torque and horsepower, because we define them by what they can do, not what they are. That's kinda like saying 'speed', say 90mph in town, costs you your license. Or 'stupid', like divorce after an affair with a 15-year-old hooker, was a bad idea. Yet, I digress - a lot.

 

Torque is a twisting force. In our context, its how forcefully the crankshaft twists a load. And the available torque changes as a function of engine speed - not because speed goes into the computation of torque but rather, because the engine twists with different strength at different speeds. However, one can see how easily dynamic parameters are confused.

 

Horsepower is a unit of power, as the name implies. Its a measure of the rate work is done. Therefore, it defines how much work, coming from the application of torque, can be done in a given time period.

 

The 5252 number is just a units conversion constant.

 

All the previous posters got the gist right. We care about what torque and horsepower can do, not their clinical definitions. But sometimes it makes a physicist like me smile to talk about it.

 

So here's a topic to make you think: We know that an engine's torque typically peaks well before the redline - the conservative engine speed limit where mechanical bits misbehave. And if that point on the torque curve is where the engine is making maximum twisting force, where should one shift??? I believe the answer is to maximize the area under the torque curve, the integral of torque from i to j. That plays into gear ratios, ratio spacing and of course, your choice of shift points - i and j. Whew!

 

BTW, thank you, George.

 

-rick

Happy Connecting. Sent from my Sprint Samsung Galaxy S® 5