What is torque in relation to car power?
- Thread starter mgblks
- Start date
Re: What is torque in relation to car power?
Sorry no I can't. The best layman article I ever read on the AIG debacle was written simply, but it was pretty long, despite that it might have oversimplified or presented more of only one side.
When a subject crosses a certain level of complexity, it is impossible to be correct/accurate without getting technical or voluminous. The best articles on the torque - power argument are all long and technical with real quantities and graphs and not subjective words.
Won't cover the basics again - only a couple critical anchors and then from there it gets easier to use your own logic and knowledge to have the rest fall in place. Pasted below are excerpts of what I've written previously on a different forum.
===
Without differentiating between crank torque and wheel torque, all is
lost. Over simplifying may be easy and fun but it won't get you in
the right direction. Over complicating is negative too and that is
never a target, but there has to be sufficient explanation.
Insufficient explanation is the reason so many are so confused about
power vs torque.
Someone who tries to optimize an engine for engine torque for a
circuit even if it requires lots of accelerating out of low speed corners will end up
getting beat by another who optimizes the same engine for best power
with decent power spread who can then gear for it, producing most
tractable wheel torque in the right vehicle speed range, and work a
little harder to keep the engine revs up (there is a human limit though).
For a given engine external or internal volume, you always want to
maximize power and power spread (the two have to go together for a given course) and then gear for it. Another way of
putting it is you want to maximum high RPM torque and its spread.
This is not the same as maximizing torque, since maximizing torque
figure means it has to happen at low engine speed (without broad limits the lower the better) since the lower the
engine speed, the harder a cylinder can be charged, lower the friction
and pumping losses, and the higher the crank torque. It is a physical
limit.. read about mach index and charging efficiency in engines.
Once you optimize for torque, it will have to happen down low, and
what little you gain in torque, will not be offset by the low engine
speed, so you end up with low peak power and narrow spread of power,
and no matter how you gear this, you only have so much power, your
mass is the same, and your acceleration in target speed range
will be destroyed.
High engine speed charging has to suffer in order to make the power for conversion to wheel torque to get up and go. Trade efficiency (power per cycle) for outright power (less power per cycle, but many more cycles in a short period of time making more power). Even American V8s as torquey are they are, make lower peak torque the more they are developed for racing.
centurion;428184 said:
Sorry no I can't. The best layman article I ever read on the AIG debacle was written simply, but it was pretty long, despite that it might have oversimplified or presented more of only one side.
When a subject crosses a certain level of complexity, it is impossible to be correct/accurate without getting technical or voluminous. The best articles on the torque - power argument are all long and technical with real quantities and graphs and not subjective words.
Won't cover the basics again - only a couple critical anchors and then from there it gets easier to use your own logic and knowledge to have the rest fall in place. Pasted below are excerpts of what I've written previously on a different forum.
===
Without differentiating between crank torque and wheel torque, all is
lost. Over simplifying may be easy and fun but it won't get you in
the right direction. Over complicating is negative too and that is
never a target, but there has to be sufficient explanation.
Insufficient explanation is the reason so many are so confused about
power vs torque.
Someone who tries to optimize an engine for engine torque for a
circuit even if it requires lots of accelerating out of low speed corners will end up
getting beat by another who optimizes the same engine for best power
with decent power spread who can then gear for it, producing most
tractable wheel torque in the right vehicle speed range, and work a
little harder to keep the engine revs up (there is a human limit though).
For a given engine external or internal volume, you always want to
maximize power and power spread (the two have to go together for a given course) and then gear for it. Another way of
putting it is you want to maximum high RPM torque and its spread.
This is not the same as maximizing torque, since maximizing torque
figure means it has to happen at low engine speed (without broad limits the lower the better) since the lower the
engine speed, the harder a cylinder can be charged, lower the friction
and pumping losses, and the higher the crank torque. It is a physical
limit.. read about mach index and charging efficiency in engines.
Once you optimize for torque, it will have to happen down low, and
what little you gain in torque, will not be offset by the low engine
speed, so you end up with low peak power and narrow spread of power,
and no matter how you gear this, you only have so much power, your
mass is the same, and your acceleration in target speed range
will be destroyed.
High engine speed charging has to suffer in order to make the power for conversion to wheel torque to get up and go. Trade efficiency (power per cycle) for outright power (less power per cycle, but many more cycles in a short period of time making more power). Even American V8s as torquey are they are, make lower peak torque the more they are developed for racing.
