How much HP does a Turbo S REALLY have? Dyno Run Video

[soawjo]

I wouldn’t understand the context of one being more important

I could be wrong but I think this argument has arisen in the context of an interview question to make sure the candidate understands that it's the power that generates torque not the other way around and at the fundamental level an engineer joining an F1 team really needs to understand that.

I won't disagree that in some contexts it may be better to consider torque over power or even irrelevant which one you use. I'm a physicist (and a theoretical one at that) so I'll let you engineers argue over the semantics of that

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[sfr]

I think @f1eng's point is at the most fundamental level it is power that generates torque not the other way around. No power = no torque. It's like arguing that it's the sun's gravity that is the most important thing in the force that it exerts on the earth. No, it's its mass that is the most important thing, the gravity is a consequence of the mass just as torque is a consequence of power

An electrical motor has a starting torque while the power is null ...

 

[JimBob]

I think @f1eng's point is at the most fundamental level it is power that generates torque not the other way around. No power = no torque. It's like arguing that it's the sun's gravity that is the most important thing in the force that it exerts on the earth. No, it's its mass that is the most important thing, the gravity is a consequence of the mass just as torque is a consequence of power

Sorry. Torque doesn't require power.

Think of nut rusted on a threaded shaft. Put a one foot wrench on it and apply a 100 lbs of force. The torque is 100 pound-ft. It takes force to create torque.

If the nut doesn't turn the work is zero and the power is zero. If the nut turns then you get work and power.

 

[soawjo]

Sorry. Torque doesn't require power.

Think of nut rusted on a threaded shaft. Put a one foot wrench on it and apply a 100 lbs of force. The torque is 100 pound-ft. It takes force to create torque.

If the nut doesn't turn the work is zero and the power is zero. If the nut turns then you get work and power.

OK, right, so it's the force from the engine that generates torque and power and the two are related by a factor of the engine speed (times a constant)? In that case, I'll admit that I don't understand @f1eng's point about power being more important than torque but I'm loath to disagree with someone who's been a F1 engineer for over 40 years (versus my zero years)

Edit: rereading the thread it seems his point is power is more 'important' than torque in that when you are designing the power train to optimise vehicle performance all you need to know is the power curve, everything is else is overcomplicating things. It's not that power is more important than torque at a fundamental level. Consider me schooled

 

[JimBob]

Agree and I don't want to put words into his mouth but for his purposes he needs power, because he needs things to happen quickly.

What is wrong is people saying torque needs RPM's. Torque is it's own thing. If you don't know what torque actually is, the formula relating torque to power can be misleading.

 

[sfr]

Agree and I don't want to put words into his mouth but for his purposes he needs power, because he needs things to happen quickly.

What is wrong is people saying torque needs RPM's. Torque is it's own thing. If you don't know what torque actually is, the formula relating torque to power can be misleading.

I do agree.
Power is the final result transmitted to the wheels and what it is needed to go fast ...

 

[Jhenson29]

but I'm loath to disagree with someone who's been a F1 engineer for over 40 years (versus my zero years)

I’m not. (Probably obvious by now…)

Sorry. Torque doesn't require power.

Think of nut rusted on a threaded shaft. Put a one foot wrench on it and apply a 100 lbs of force. The torque is 100 pound-ft. It takes force to create torque.

Exactly. This is force without a distance. No work is being done.

all you need to know is the power curve, everything is else is overcomplicating things.

But the power curve and torque curve aren’t really different at that point. They’re just different ways of looking at the same thing. “Overcomplicating” is a matter of opinion or application.

 

[Gwaihir]

I’m not. (Probably obvious by now…)


Exactly. This is force without a distance. No work is being done.


But the power curve and torque curve aren’t really different at that point. They’re just different ways of looking at the same thing. “Overcomplicating” is a matter of opinion or application.

When I was designing high frequency motor drives for an automotive company it was all about current! I just needed drive electronics that didn’t blowup at full current switching at 30kHz. That was the main driving factor. Oh, it also had to work from -40C to 125C.

 

[soawjo]

But the power curve and torque curve aren’t really different at that point. They’re just different ways of looking at the same thing. “Overcomplicating” is a matter of opinion or application

Yeah, that’s what I’d conclude with my limited knowledge of this but like I said I’ve had zero years experience designing cars for motorsports whereas f1eng has had 40+ so I’m happy to defer to him

 

[Jhenson29]

When I was designing high frequency motor drives for an automotive company it was all about current! I just needed drive electronics that didn’t blowup at full current switching at 30kHz. That was the main driving factor. Oh, it also had to work from -40C to 125C.

30kHz is higher than anything I deal with. I’m usually working with 2 or 3. Sometimes 6 or 8.

What’s driving that need (pun intended)?
Output frequency? Motor thermals?

Did you have a load reactor?
What current?

Sorry for the 20 questions. I just find it interesting.

 

[Jhenson29]

Yeah, that’s what I’d conclude with my limited knowledge of this but like I said I’ve had zero years experience designing cars for motorsports whereas f1eng has had 40+ so I’m happy to defer to him

This is all fundamental. It doesn’t matter if it’s a car, or an uncoiler, or a pump.

I really thought it more this afternoon. This is as succinct I could get it.

• Fundamentally, a motor produces torque.
• The rate it produces that torque is power.
• Power and torque are different things, but they are related by rpm.
• Either number without taking speed into account is worthless. You have to know what speed you will be operating in.
• If you are dealing with a fixed speed application, then a single value at that speed will suffice, otherwise you need to look at the curve relative to that speed over the operating range.
• Because power and torque are related by rpm, their curves over rpm contain the exact same information.
• Therefore, in any sense that matters, knowledge of power or torque is equivalent.

Edit: To be perfectly clear @f1eng is not wrong that you need the power curve for the application. I just disagree that the torque curve is not equivalent.

Edit 2: That said, I also disagree with your blind faith in authority.

 

[JimBob]

A small point. A motor creates a force in the form of torque.

 

[soawjo]

That said, I also disagree with your blind faith in authority

Haha, fair enough. It’s just I find that the cliché “a little knowledge is a dangerous thing” is very often true. I’ve had people telling me I’m wrong about things I know from my job I spent 15 years doing and it’s very frustrating. I imagine f1eng is experiencing something similar here. I hope he doesn’t mind me saying, if you didn’t know f1eng is Frank Dernie. Look up some of his videos on YouTube. He isn’t some chancer that did a bit of back room work for a minor F1 team, he played a big part in several technical innovations in motorsport. I’m very wary about telling him he’s wrong about this

 

[Jhenson29]

It’s just I find that the cliché “a little knowledge is a dangerous thing” is very often true. I’ve had people telling me I’m wrong about things I know from my job I spent 15 years doing and it’s very frustrating.

I would think, as a physicist, you would be able to reason through it and decide for yourself. But I’m not a physicist, so perhaps I’m overreaching. That’s not a dig. It’s just my naive opinion.

I imagine f1eng is experiencing something similar here.

Again, I don’t think he’s wrong about his method and I believe it gets him the correct answer. But that fact that gets the right answer doesn’t exclude other equivalent methods.

…f1eng is Frank Dernie. Look up some of his videos on YouTube. He isn’t some chancer that did a bit of back room work for a minor F1 team, he played a big part in several technical innovations in motorsport.

I’m happy to retract my statements and apologize for my arrogance if someone can show I’m wrong.

 

[Jhenson29]

A small point. A motor creates a force in the form of torque.

Yes. I agree.

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