Will the Lucid Air Be Faster Than a Tesla Model S Raven?

For our first automotive mathematics class, we’re going to tackle two self-serving math problems. Both involve a car’s weight, the latter involving how quickly a vehicle can accelerate based on its power-to-weight ratio. From this, we will be able to determine if Lucid can build an electric car that can out-accelerate Tesla’s blistering Model S Raven.

Before we get to that, however, we have to unpack how we weigh our test cars here at MotorTrend.

Our test vehicles arrive at Auto Club Speedway in Fontana with the cars topped off with gas. There’s usually four to six vehicles—a big day might be eight or nine. Road test editor Chris Walton, associate road test editor Erick Ayapana, and road test analyst Alan Lau check in the cars, ensure all is set, and line them up to be weighed.

To do this efficiently, we position two 2.5-inch-tall electronic weighing pads with plastic ramps for the cars to drive up. The car pauses on the pad, the driver hops out to record the front axle weight, then hops back in and then drives down, so the whole process is like driving over one long speed bump. The car then glides forward, and up goes the rear axle (driver hops out), it’s weighed, then it rolls off the scales. On to the next car.

All we have to do is skootch the pads and ramps slightly narrower or wider to accommodate the approaching car’s different track widths (instead of repeatedly positioning four scales, pulling out of the way, then positioning them, again and again). It’s an assembly-line-like process.

But, you may ask, is weighing one axle at a time accurate?

Problem 1: The Small-Angle Approximation

I’ve been asked this many times, and I say it’s close enough. But what do I mean by that? In the last couple of weeks I’ve been weighing our test cars by both methods (and sometimes twice to note repeatability) to give you, our online students, some numbers to consider.

Here are the results:

In this chart, what matters are those four bottom rows. Our quick, two-pad method is usually underweighing by about 22 pounds, or less than 0.5 percent (one-half of 1 percent). That’s about five times the average repeatability we’ve found when reweighing the same car by the same method, but knowing any measurement to 0.5 percent is still stupendously good.

But why is it there at all? Elevating either end of the car by 2.5 inches slightly tilts it (for Sedan 1, it’s about 1.4 degrees). The car’s center of gravity tilts the same 1.4 degrees away from the scale, and depending on the CG’s height, minutely reduces the measurement. Raising one end of the car by a lot more than 2.5 inches (at least 10) is one way to calculate the center of gravity’s height, but a mere 1.4 degrees is too small. So small that we can happily accept this small-angle approximation.

Problem 2: Power-to-Weight-Ratio

Recently, I had a conversation with Peter Rawlinson, CEO and CTO of Lucid Motors, who mentioned that a future version of their upcoming sedan, the Air, would offer a three-motor arrangement (two in back, one up front, akin to the future Tesla Model S’ Plaid powertrain) that’ll total 1,800 hp. That prompted a question from editor Mike Floyd: Can you calculate how quick that car will be?

We’re concocting this prediction from some pretty flimsy information, so don’t hold me to it, but here goes:

On Lucid’s website, the 1000-hp version of the car is claimed to accelerate to 60 mph in less than 2.5 seconds. We’ll just call that 2.5, and now we’ll consider how the 1,800 hp that Peter mentioned, would shrink that even further. For weight, let’s use the (Raven-drivetrain) Model S Performance’s 4,987 pounds as a proxy for the Air.

Since we started compiling road test data, there are 4,705 rows in our database. Of them, just 41 are battery-electric cars. Less than 1 percent of our total testing universe. Nonetheless, if we plot all these EVs’ lb/hp against their 0–60 time, an encouraging pattern appears.

I’ve colored their dots to distinguish whether they were FWD (slowest), RWD (quicker), or AWD (all Tesla Dual Motor cars and the Taycan) plus a reasonable-looking, linear curve to fit along with its equation.

So, Will the Lucid Be Faster Than the Tesla?

Let’s enter the 1,800-hp Lucid’s estimated 2.77 lb/hp and see what it tells us. Our mathematical calculations determine a 0­–60 mph in (get ready) 1.25 seconds. That’s that big dot in the lower left corner of that chart above.

Sounds incredible. And frankly, it is. It’s also imaginary. If we simplistically assume the Air were to accelerate at a constant rate, that reflects a continuous 2.2 g’s. Only heated racing slicks can handle that sort of accelerative force—current road-car tires are clearly not up to the task. So, what is a realistic acceleration rate for the Lucid Air?

The Model S P100D Ludicrous we tested a few years ago retains our quickest 0–60 time at 2.28 seconds after accounting for roll-out (we’re adding a decimal point beyond what we typically report because the numbers are so close). During and shortly after it launched, the car’s finely honed traction-control system appeared to saturate its tires’ grip with power, for an instant pegging its acceleration rate at 1.26 g before falling off as power fades and aero loads grow.

However, 1,800 hp has the potential to saturate the tires for a considerably longer time. If we extend the same 1.26-g acceleration for the whole run, we calculate a 0–60 time of 2.18 sec (raw) or a hair below 2-flat after subtracting the 1-foot roll-out time as we always do.

There’s my answer: Hyper-powerful EVs are scraping against their limits of acceleration (with current tire technology), though it can still be interestingly exercised at top speeds (Lucid claims the 1,000-hp Air will exceed 200 mph).

Thus ends the first session of MotorTrend University. But before you go, your homework is to come up with some interesting car-testing questions for me. Email: Kim_Reynolds@motortrend.com.

Class dismissed.

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