Lucid Motors CTO: An EVs Torque Number Is Irrelevant

FEB 18 2019 BY BRADLEY BERMAN 51

The name of the game is acceleration at the wheels. Not motor torque.

It’s common practice for EV producers to report the torque of the car’s electric motor. But Peter Rawlinson, Lucid’s chief technology officer, believes that absolute numbers used to describe the torque of an EV motor are useless. “Torque is an irrelevant thing to quote,” he told InsideEVs. “I’m not interested in torque.”

Rawlinson was the chief engineer on the Tesla Model S. He previously held top engineering positions at Jaguar and Lotus.

“Suppose one motor can spin twice as fast as another one and the one has half a torque of the other. They produce the same power,” Rawlinson explained. “The one that can spin twice as fast but has half the torque, you have twice the reduction ratio. The zero-to-sixty speed time would be identical,” said Rawlinson.

It’s a fine point. Rawlinson obviously understands that a chief advantage of EVs is their quickness. His objection is about quoting the torque value of, say, the Tesla Model 3’s motor at 317 pound-feet versus a Bolt’s 266 or an E-Golf’s 214 lb-ft.

Lucid Air at Laguna Seca

“Touting the instantaneity of torque, the maximum torque from zero rpm you can get from an electric motor, are tangible, valuable attributes. And they’re real,” he said. “But what matters is the torque at the wheel not the torque of the motor.”

Overall Acceleration

I reached out to Sam Abuelsamid for his perspective. Abuelsamid, a senior analyst at Navigant Research, agreed with Rawlinson that a motor with lower torque that spins faster, combined with the appropriate gear ratio, will indeed provide the same performance. But he added, “There are however limits to that.”

Abuelsamid said that an electric motor has a speed at which torque begins to fall off. The curve stays flat up to that point and then decays. “If the motor torque is too low and it requires high speed, you will hit a wall.”

Abuelsamid explained that’s what happened to the original Tesla Roadster. “It’s the reason they originally tried to use a two-speed gearbox to hit the performance targets,” he said.

Rawlinson’s emphasized that the transmission and the motor are a single system. “My transmission team and my motor team work together in the same area,” he said. “They are working on a single rotational system.”

Abuelsamid agreed with Rawlinson’s overarching point. “The only number that is actually meaningful is the overall acceleration,” said Abuelsamid. “Anything less than about 10 seconds from zero to 60 is going to be more than adequate for any ordinary driving.”

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51 Comments on "Lucid Motors CTO: An EVs Torque Number Is Irrelevant"

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The 0-60 fetish also needs to end at some point. Most cars I have owned whether EV or ICE have had 0-60 times between 6 and 8 seconds. That is plenty fast. Too many of these cars with insane levels of torque and power (and widely publicized high speed crashes like what we’ve seen) will put off the average consumer. If EVs are stuck with the reputation of being the play toys of irresponsible, wealthy young men, that will be far harder to grow out of among families and average consumers than the smug, granola, tree hugger reputation the Prius got stuck with.

That’s one man’s opinion. Choices are the litmus of success for EV’s, just like any other product, it’s one of the main reasons that EV sales have languished in the beginning, because range and performance were so limited. What may be fine for you isn’t for the next person. My Model S has 3 different acceleration modes because of that very fact. Paul Walker was killed in his ICE Porsche because he was irresponsible- you don’t harm the masses for the exceptions.

If the power is too much, simply program your Tesla for ‘Chill’ and sit back and enjoy having the option.

His point still stands. EVs and Teslas specifically are selling to a very specific crowd right now. But, people buy huge amount of cars with greater than 8 second 0-60 times. For the CUV and SUV craze that’s probably one of the last stats you look at.

My point still stands, too. The SUV and pickup crowd absolutely care about power, hence the incredible horsepower and torque that present day ICE trucks and SUVs possess compared to even 10 years ago. Instant torque was noticeable in my 2012 Leaf well before I had my Tesla. People like options, and I’m sure if you asked someone with a Prius if they’d prefer quicker acceleration, the vast majority would say “yes.”

Just because you want a slow car doesn’t mean all the cars sold have to be slow to your pace.
Imagine your great grandpa wants an even slower car and he said every car should go no more than 45mi/hr.

John said:

“Paul Walker was killed in his ICE Porsche because he was irresponsible…”

Nope. Get your facts straight. Paul Walker was a passenger in a Porsche that was owned and driven by his friend Roger Rodas when he died in a horrific crash.

Well, his friend forced him in the car so he didn’t have a choice. Right?

Paul wasn’t the driver

How many people are willing to put a car seat and baby into a car that is in the news for Paul Walker’s fiery death?

Sorry, whether or not Paul Walker was driving has little to do with my point that ICE vehicles with quick acceleration still breed irresponsibility from some. The guy driving him was the irresponsible one, my mistake.

The Nissan Leaf is an electric car. And it doesn’t have that reputation. And you can still get killed in one.

Weird opinion

Not to mention insane insurance costs.

Ron Swanson's Mustache

One of the biggest selling points for EVs is that, for a number of performance indicators, the EVs easily outperform their ICE counterparts.

Deliberately nerfing the performance of what are supposed to be performance vehicles, just to please a small coterie of moral scolds would instantly revert EVs back to being niche vehicles that only appeal to people who hate cars and driving.

Finally someone who gets it!! Power, Watts, is everything!

Quoting torque on an electric car is a totally useless carryover from combustion engines. And even there it was questionable.

A petrol engines torque curve can be totally different from another, so having a car with more torque meant higher power at lower revs, despite maximum power being the same. That’s important for petrol cars, because they have multiple gear ratios and you want to stay at low revs for efficiency.

With EVs you only have a single gear ratio and constant torque until you hit peak power. So as long as the peak power output is the same and you reach it at the same speed, motor torque actually doesn’t matter at all.

Hell yes!

The only reason torque means anything for ICE is that it indirectly measures a second point on the power curve.

It means next to nothing for an EV.

I remember Fisker talking about high motor torque just needing a 2-speed transmission to get supercar performance. Clearly no engineering ability…

May I ask WTF all these thumbs down are for? An EV supercar needs high power, not necessarily high torque.

Regarding Fisker:
https://www.autoblog.com/2011/07/22/multi-speed-gearbox-fisker-karma-performance-veryon/

Are these guys still in business?

It all boils down to horsepower.

From above: “Power, Watts, is everything!”

Horsepower are for horses

Horsepower never was for horses. Horsepower and Watts are both units of power.

There are no horses involved with an an electric motor.

Only torque.

Wrong.

Horsepower is calculated by using the torque value / 5252.

If you have less torque at the motor you will have Less torque at the wheels .. “Torque & Load Are Of Ultimate Importance” … MOTOR TORQUE IS OF VITAL IMPORTANCE ! To Achieve The Desired Torque “AT THE WHEELS” **** 🙂 *** Try Pulling a Heavy Boat Out Of The water , Up A Boat Ramp With a High RPM Motor That Has Little Torque .. “IT WILL NOT HAPPEN” …….*** 🙁 ***…… Mr. Engineer !

You are COMPLETELY missing the point of what this article is about. A motor with low torque rating can be compensated for by gear reduction. He is saying the measure of the system as a whole is what matters.

You are so, so wrong in your boat ramp analogy. For decades before people have come to believe that you have to have an enormous diesel engine to pull a boat out of the water, people were quietly doing it with small gas engines in trucks that had manual transmissions equipped with a “Granny gear”. In fact, the boat storage yard where I live pulls all manor of boats out of the water with bone stock Jeeps with 6 cylinder gas engines and manual transmissions with a Granny gears. Everyday, all the time.

Those little Jeeps are the most cost effective and efficient boat pulling machines ever invented. Monster quad cab, duelly, lifted Cummins diesel powered pickup, need not apply.

He said, “But what matters is Torque At The wheels ,Not Torque at the Motor” You got to Have TORQUE AT THE MOTOR 1st. “THE MOTOR MAKES THE TORQUE” …Before you Can Have any amount of TORQUE AT ALL* TO THE WHEELS .He is FOS .Talking Out Of His Butt. Who’s Missing the Point ?… 🙂

You are taking the Lucid guy too literally. Obviously the motor has to generate some torque. What he was talking about is the ability to multiply torque using gears at the expense of the maximum speed that can be achieved at the wheels.

You don’t understand because you know nothing about physics. You are the uneducated one talking out of your ass.

He did not say there is no torque. He said the torque rating of the motor doesn’t matter, and only power does. That is correct.

Which will produce more torque at a wheel rolling at 30mph?

A: a motor producing 200 ft-lbs at 6000 RPM and going through a gearbox

B: a motor producing 500 ft-lbs at 2000 rpm and going through a gearbox

all manner, it’s not a house.

The article’s point has not been missed – it’s just not a very good one.

Who the hell is tossing out all these thumbs down? You are completely correct!

Power output is all you need at the engine. A motor that outputs 200 ft-lbs of torque at 20,000 RPM will destroy a motor that outputs 1000 ft-lbs of torque at 2000 RPM at any job, whether it’s pulling a boat or accelerating a vehicle.

Do you know, International Harvester had a turbine powered tractor with less than 8 pound-feet torque. It was a fuel hog, but it could pull just fine, because it had the power.

A high speed low torque motor can be turned into a low speed high torque motor using gears.

Wow, a CTO looking at a basic law of physics but ignoring the bigger picture of engineering? Achieving the same power at lower rpm is usually more efficient, which is very important to an EV. It’s also quieter, which is generally preferable to a driver and passenger.

Torque matters, with thinking like that its no wonder Lucid is still vapor.

Somebody needed ‘talking points’ to attract more media coverage; A more prescient conversation-starter would go something like this: I have a hangnail, do I use a nipper or bite my nails off?

“Anything less than about 10 seconds from zero to 60 is going to be more than adequate for any ordinary driving.”

No, no and no. Whoever said this is still living in the past.
Every car in the future should have good acceleration of less than 6s as an option.

Headline: Lucid Muddies the Waters.

I’m surprised at this community’s anti-math and anti-science stance on torque. Please look up how gear reduction affects torque at a given power.

Torque tells how powerful your motor is, which tells you a bit about the car’s performance.
You never look at torque alone but analyse it with other specs of the car.
Look at it this way, if someone told you mile/gallon of a car without the weight and capacity of the car, then that consumption is useless as well.

Actually, if you know the mi/gal then all you need to know is how many gal do you have. If it goes 25mi/gal and you got 1 gal, you’re only going 25mi.

So basically what he’s saying is that their own car which they still haven’t produced is slower than the slowest Tesla. Got it

Lucid is a fail – I doubt they will ever make it to market

If there are two motors with same power, but other motor has half torque and twice max rpm, and the shape of the power curve is same, then the performance is exactly same. Same 0-60 time, same quarter mile time and same top speed.

This is not to say that torque is meaningless value. It isn’t. But the max torque alone doesn’t tell much of anything without knowing the max rpm. Full power curve would be even better information.

Looks like the model 3 of tesla

In other words, look at the horsepower, not the torque.

Torque itself doesn’t matter. Any engineer would know that it is just a point off a curve in a graph.

Torque curves vs. RPM really matters. Of course, that is just a display of power. Power = torque x rpm.

Gearing just changes the torque at any given rpm to the wheel. Ultimately, it is still power curves that determines how fast a car can go.

No, it doesn’t all boil down to power. Wheel torque is what supplies the tractive effort, the force the tires apply to the road, and that is the force that accelerates the car: a = F/m = T/mr where T is torque and r is the tire dynamic radius. At lower speeds when the vehicle is in early stages of accelerating the power is quite small since the power output of an electric motor is the product of torque and angular velocity (rpm). The power increases linearly with rpm up to base speed of the motor, the speed where it torque then begins to slowly decrease with rpm. Higher rpm than this is generally referred to as the “constant power” part of the torque-speed curve. Torque is what determines acceleration rate. Power determines up to what rpm you can maintain peak torque. Most manufactured electric cars are designed to provide peak torque up to base speed. The Lucid guy is correct that it doesn’t depend directly on MOTOR torque, but the motor has a maximum rpm, so one can only adjust with a gearbox (a torque multiplier) over a limited range. In the end, the motor must have sufficient torque.