From the April 2023 situation of Motor vehicle and Driver.
You cannot let some curbing stand in the way of a fantastic lap time, specifically at Virginia International Raceway, exactly where it is really ideal to clip nearly as quite a few as achievable to set a aggressive lap. Snake is just one this kind of portion, and the Lucid Air Sapphire prototype I’m piloting glides more than the concrete serrations as if created to do very little else and then rockets toward the Climbing Esses. More care and selective control skimming operate greater listed here. Next, the limited Oak Tree corner gives a different gentle dose of apex clobbering. The correct-hand detour into VIR’s inner loop will come up rapidly, but the Sapphire’s humongous 10-piston front brake calipers squeeze trackworthy carbon-ceramic rotors to haul this cruise missile well down to transform-in pace without a trace of squirm or squiggle. The vehicle bends as a result of the lower-velocity horseshoe smoothly with perhaps a hiccup at the exit. Then it can be off to Spiral and the diving left-proper mix that will come just in excess of a blind crest.
“Whoa! That was a major twitch.” There is certainly a further slight electricity interruption when I graze the very low suppress at the exit of Spiral, but the motor vehicle reasserts alone via the relaxation of the Infield. The Sapphire looks to really like Roller Coaster, but as I exit Hog Pen and set my sights on the Entrance Straight, the car walks towards the left edge of the observe, robbing me of the assurance to plant my correct foot. With a whole lap less than my belt, it can be time to return to the pits for a debrief. After that, we are going to contemplate creating some alterations.
This approach isn’t really solely new territory for me. Ahead of journalism, the perform that place food on my table was evaluating and tweaking the suspensions of prototypes in growth at proving grounds, racetracks, and even public roads when plan driving character was underneath scrutiny. But my concentrate was usually on tuning the hardware—springs, dampers, anti-roll bars, tires, bushings, etc.—because none of the suspensions I worked on had a line of program code involved with them.
John Culliton, ace driver and senior technological professional in Lucid’s chassis and motor vehicle dynamics division, retains a position comparable to the one I at the time experienced. He rode shotgun so we could explore the car’s conduct on the fly. After we untangle ourselves from the prototype’s 5-stage harness and duck below the entire roll cage, calibration and validation manager Esther Unti joins us at the car’s trunk, which has a raft of details-logging equipment and a port into which she now plugs her laptop computer.
Creator Edmunds, a former chassis engineer, is also a dad. Below he shows the Lucid crew the great burping strategy.
Michael Simari|Car and Driver
They look gratified to corroborate my responses with their have, which is important since it really is critical to differentiate between what the automobile is executing and what a driver is accomplishing. This is the initial time the Sapphire has tackled VIR’s Grand System, and a test crew have to achieve a specified level of track familiarity ahead of driver tuning can give way to vehicle tuning.
But this is significantly from the Sapphire’s initial tuning session. Quite the contrary. Chassis and vehicle dynamics director David Lickfold and his staff have visited a lot of tracks and proving grounds. They have so much dialed in the specification of the purely mechanical bits—those points I utilised to tune—and the inner building of the bespoke Michelin Pilot Sport 4S tires.
Lickfold and enterprise have also settled on a base mechanical valving for the electronically managed Bilstein dampers, which mainly perform without having any electronic valve adjustment in the base Easy driving mode. Program-controlled rebound and compression-damping valves include supplemental damping throughout intense activities in this method, but they come into their individual, routinely adapting with excess damping in Swift method, then kick that up yet another notch in Dash. The workforce has also landed on a energy-steering-help profile for every method, as effectively as the manner-dependent actions of the Bosch electromechanical brake booster that blends the massive friction brakes with the car’s significant possible for regenerative braking.
In garage range 3, engineers get a whole debriefing on what worked and what did not operate as they inch closer to a ultimate calibration.
Michael Simari|Auto and Driver
These basic elements come to feel properly ironed out, and even however Lucid did not formally lock them down, they stand at close to-production status. What does that depart for this VIR session? The engineers are nevertheless tweaking the damper software in Swift mode, but the Sapphire’s ability to shrug off curbs tells me they’re near. That predominantly leaves anything I in no way had to deal with in my engineering vocation: controlling the torque developed by the Sapphire’s insanely strong 3 motors.
A normal Lucid Grand Touring athletics at every single finish a single motor made up of a cleverly integrated differential within just an impressively compact coaxial motor housing with outputs on the motor’s centerline. Each and every motor is able of 670 horsepower, but the GT’s complete 1050 horsepower is a lot less than the mixed sum of both equally. That’s mainly because the GT’s 112.-kWh battery cannot place out as much energy as the Sapphire’s 118.-kWh pack. This distinction also clears the way for uneven significant-load torque splits.
In the Sapphire, the very same 670-hp device resides up front, but the rear finish consists of a pair of all those motors in a shared housing. Mainly because each individual rear wheel is independently managed, the rear axle has a scary 1340-hp likely, and the sum of all a few motors is a staggering 2010 horsepower. Lucid will only cop to a complete mixed output of 1200-furthermore horsepower, with a definitive number some weeks away. But the variation in between regardless of what that placeholder signifies and 2010 implies a serious quantity of torque-vectoring likely. That delivers us again to Unti’s laptop and why Lucid is at VIR.
This powertrain gives Culliton and Unti a great deal of tuning flexibility, but they need to account for a lot of different performance-driving situations. In a straight line, there is practically nothing halting them from sending all the battery can muster to the rear axle—except sanity and physics. You can usually get a quicker and a lot more secure launch when a lot more than two tires put torque to the ground. To that close, they tell me that about 75 per cent of launch torque goes to the rear. Even at the drifting stop of the spectrum, they nevertheless send out a little bit of torque to the entrance “to make slides far more predictable and achieve bigger sideslip angles.” Cool.
VIR’s Grand System lies concerning all those two efficiency extremes, with a selection of corners. That’s what can make it these a terrific site for our once-a-year Lightning Lap exam and a helpful place to kind out the Sapphire’s intricate torque vectoring, which goes way beyond simulating the differential motion that arrives normally to a single-motor drivetrain. Torque vectoring in an EV with two motors on a single axle can generate power a lot more speedily, specifically, and efficiently than commonplace brake-based torque vectoring. And the degree of break up is remarkably variable because just one motor can regenerate power whilst the other drives ahead.
Unti’s notebook, loaded with Lucid-designed manage plans, manages all of these options. In reality, some 90 percent of the traces of code inside the Sapphire have been composed in-residence. The software Unti is functioning with now lets her and Culliton to change parameters that subsequently rewrite fundamental code appropriately. For illustration, the wheelbase module reallocates torque to mimic the feeling of a bodily shorter or lengthier wheelbase, dependent on problems.
Culliton and Unti punch in a handful of tweaks to tackle problems I encountered. For superior-pace exits, this sort of as when coming out of Hog Pen, they up the degree of rear torque vectoring to add a bit of rotation as I transition from component throttle (they use the word “throttle” as opposed to “accelerator” or some other unsatisfying time period, so I will too—this the moment) to Front Straight acceleration, so I get previous the sensation that introducing far more will enhance understeer. In the dramatic Spiral changeover, they soften vectoring and reduce the change-in instant so as not to overwhelm the rear tires. And in the scenarios where by the again conclusion twitched on corner exit, they add a bit much more front torque bias for rear stability.
They failed to tell me any of this before I went out in the Sapphire once more, lest I foresee the effects. But the adjustments worked a handle. The two minimal corner-exit wiggles disappeared, and the vehicle was substantially more steady when I crested the reduced-pace transition in Spiral. Finest of all, I was greater able to feed on the electricity as I exited the closing convert. The phrase “deficiency of self esteem” disappeared, changed by “my God, this factor is quick.”
There was a facet influence, while. As is frequently the scenario in tuning, when you make improvements to one particular thing, you eliminate out someplace else. That occurred in Roller Coaster, where the Sapphire became a bit twitchier. A miscalculation on my component may well have introduced that about as I sailed a handful of feet past my standard transform-in point and tried using to convey it back. The automobile appeared to consider to aid, but below two wrongs did not make a correct. Back again to the pits for another believe and software package tweak.
At this issue, my time was up, but Culliton, Unti, and Lickfold were being heading to stay at VIR for an additional spherical or two in advance of packing up and transferring on to another screening locale. It’s going to be wonderful to see exactly where the Lucid Air Sapphire ends up when they are concluded, but points appear extremely promising in truth. Let us hope we can get our hands on just one for the upcoming Lightning Lap.
Sapphire vs. Plaid
It is really tempting to seem at the Tesla Design S Plaid and the Lucid Air Sapphire by the exact lens. Right after all, each has a tri-motor powertrain that creates upward of 1000 horsepower. But there are essential distinctions.
For one particular, the Sapphire was portion of the Lucid Air sport strategy from the begin and will look in the model’s next yr of production. David Lickfold informed us his team knew of the need to set down all that massive electric power and torque when they originally conceived the suspension. The similar is correct of the objective to make the motor vehicle utterly trackworthy, which implies its 10-piston entrance calipers and carbon-ceramic brake rotors are no afterthought.
In the meantime, the Plaid emerged in the Model S’s 10th design year. It can be doubtful that Tesla prepared the Plaid’s existence that significantly out, particularly considering the fact that the enterprise constructed its model all-around the induction motor that Nikola Tesla invented, a stylized cross area of which is Tesla’s brand. But in 2019, Tesla quietly started off abandoning induction motors in the Design S, switching to everlasting-magnet synchronous ones, and the Plaid would not have been feasible if that hadn’t occurred.
What is actually far more, the Design S Plaid shares tires and brakes with the less potent variant. All- year 19-inch tires stay typical, with 21-inch summer rubber an solution. The Plaid is predominantly a motor swap. A $20,000 carbon-ceramic brake up grade kit is prepared for later this yr, but it need to have been aspect of the Plaid package from the starting.
Dan Edmunds was born into the world of vehicles, but not how you may believe. His father was a retired racing driver who opened Autoresearch, a race-vehicle-constructing store, exactly where Dan reduce his tooth as a metallic fabricator. Engineering college followed, then SCCA Showroom Inventory racing, and that combination landed him suspension development employment at two different automakers. His crafting career began when he was picked up by Edmunds.com (no relation) to build a screening office.