Earlier this year McLaren unveiled the Artura, a new plug-in hybrid supercar that essentially replaces the Sports Series lineup of cars. Chief Engineer Geoff Grose said the Artura was McLaren's biggest engineering project since the MP4-12C that launched the brand's production road car program back in 2011. But more than that, as McLaren's first series production hybrid, it's likely the company's most important road car of all time -- and yes, maybe including the game-changing F1.
Speaking to members of the media last week, McLaren detailed the Artura's completely new engine, chassis, design and development. Now, we've distilled all the juicy details for you.
Chassis and dynamics
Everything starts with the Artura's carbon-fiber monocoque chassis, which is brand new from the ground up. Called MCLA, for McLaren Carbon Lightweight Architecture, it's the first time that chassis development was brought totally in-house. This resulted in a four-year development time and an investment of close to $600 million in a new facility in England.
The build process for McLaren's previous monocoques used to take 4 hours, and only 20% of the process was automated. With MCLA it takes just 1 hour and over 70% of the process is automated. MCLA is made up of over 500 individual parts that combine into 72 preforms, which then make up 11 subassemblies that are placed in a multipiece tool that is closed, resin-injected and cured in a mold.
McLaren decided the Artura would be a hybrid from the very beginning, so MCLA was developed with that in mind as well. The enclosure for the 7.4-kilowatt-hour battery pack underneath the floor is an integral part of the monocoque; it sits on a carbon plate that's also part of the chassis and is bolted in place. This means the battery pack is well protected, too, and it enhances structural integrity and lowers the car's center of gravity. As a whole, MCLA is stiffer and stronger than McLaren's old monocoque, and filled with fluids the Artura weighs 3,303 pounds, only 175 pounds more than the 720S.
The Artura has new electrical architecture, as well. The brand's old cars used a CAN-based architecture, but given new technologies like driver-assist systems, more powerful stereos and new infotainment features, the Artura needed a new setup that would be future-proofed. The new ethernet-based network has 25% less cabling and a lot less physical complexity, making it 10% lighter than the 720S' setup. It has only four domain controllers vs. the 720S' 12, and new over-the-air updates cover 70% of the key modules, further reducing complexity. Like MCLA itself, the electrical architecture was developed in-house, giving McLaren more flexibility.
Grose said McLaren never changes things just for change's sake, there has to be a legitimate performance reason. To that end, it's not just the monocoque and platform that are new. McLaren is sticking with a hydraulic steering setup, as its customers care about the feel and feedback that a hydraulic system affords, but a new variable thickness anti-roll bar saves 3 pounds over the old design. The Artura has a totally new multilink rear suspension design for better stability and driving dynamics, and the suspension's packaging is improved to boot. The Artura also uses Pirelli's new Cyber Tire, which has Bluetooth sensors for accurate temperature and tire pressure measurements; these tires also allow drivers to set precise target pressures in Track mode.
Powertrain and hybrid system
The Artura's M630 twin-turbo 3.0-liter V6 is completely new, sharing nothing with the V8 that's been in use since the MP4-12C. It was meant to be paired with a hybrid system from the outset, as hybrids offer better efficiency and engine response. On its own the engine produces 577 horsepower and 431 pound-feet of torque, nearly as much as the 12C originally did, and the V6 revs to an 8,500-rpm redline.
At 353 pounds the Artura's V6 is 110 pounds lighter than the 720S' V8, and the V6 is both 7.5 inches shorter in length and 1.6 inches lower in height than the V8. Moving the camshaft chain to the rear of the engine places the cam phasers over the transmission, which helped to reduce the overall length, as did giving it a smaller bore with Nikasil-coated bores directly cast into the block, reducing the space between them. The V6 has a hot-vee layout, which means the turbochargers are mounted inside the 120-degree V of the engine, saving a ton of space and letting the turbos spool up more quickly. Most hot-vee engines are found in front-engine cars, so it was a major packaging exercise to create the Artura's motor.
Richard Jackson, McLaren's head of powertrain, said McLaren really focused on making sure the Artura would sound good without using any artificial enhancement, and the hot-vee setup helps with that. The exhaust tips are mounted high up on the rear deck, and because of the location of the turbochargers, there's a straight run for the exhaust gases from the turbos to the rear. The lack of bends minimizes power losses and maximizes the noise, and there are resonators ahead of the tailpipes that amplify higher-frequency noises as revs increase. Through the movement of sound waves a permanent diaphragm links the exhaust noise into the interior without letting gases come in.
The Artura's disc-shaped electric motor is placed at the "heart" of the car between the engine and transmission, sitting inside the clutch housing on the transmission input shaft. Its compact installation was inspired by the P1 and Speedtail's setups, and it weighs just 34 pounds and produces 166 lb-ft -- the P1's electric motor made 192 lb-ft but weighed 84 pounds. It's an axial flux-type motor, which means it creates magnetic flux to generate torque in parallel to the rotation of motion; this setup maximizes torque and reduces space compared with other motor types. It also can sustain higher power for longer periods of times, key for a performance hybrid.
McLaren says the Artura will be able to go 19 miles on electricity alone -- more than double what the Ferrari SF90 will do and even besting the BMW i8 -- and it can reach speeds of up to 81 mph in EV mode. Using a Level 2 charger the Artura can gain an 80% charge in 2.5 hours. The sound in EV mode was carefully considered, too. To make the car totally silent a ton of sound deadening would need to be added, meaning a ton of weight would need to be added, so instead McLaren made sure the electric motor's unique noises would be audible, increasing the driver's engagement when in EV mode.
In the Comfort drive mode the Artura has what McLaren calls "extended start/stop behavior," which basically means the internal combustion engine will stay off for longer periods of time. It will stay under electric power until 37 mph, at which point the engine turns on, and it will shut back off below 24 mph. Put the car in Sport mode and it'll be more engaging, with the engine always on and the battery maintaining a higher state of charge. Track mode is for ultimate performance, with the engine and electric motor at their most aggressive settings, the battery keeping the highest state of charge possible and replenishing quicker than in the other modes.
With the electric motor in play the Artura has a total output of 670 hp and 531 lb-ft. Not only does the Artura have the highest specific output (horsepower per liter) out of any V6 currently on sale, the only McLarens that beat its specific output are the Senna and Elva. The electric motor helps to fill in at the lower end of the torque curve, and torque delivery is managed by a new electric control system and McLaren's first electronic rear differential that provides more agility at low speeds and better stability at high speeds.
Sunoj George, head of McLaren's electric drivetrains, said the Artura's hybrid system is "a snapshot of what's gonna happen in the future," a not-so-subtle hint that more hybrids (and fully electric cars) are on the way from the brand.
Design and engineering philosophy
McLaren Design Director Robert Melville described the Artura as "a piece of pure technical sculpture," and says that its design was completely influenced by the engineering goals -- function over form to the fullest extent. New digital technology like virtual reality lets the designers complete extensive processes and make adjustments in a matter of days, much more quickly than for previous cars. The engineers also used computer modeling for the aerothermal management and cooling system development, as modern cars are exceedingly complex and can be a mess of hoses and pipes and wires. Modeling everything virtually makes it easier to integrate all the systems and components with confidence, and quickly test out new ideas.
Product Manager Thomas Taylor said the targets for any new McLaren are determined by a list of eight subjective attributes that are arrayed in a spider chart, with overlays of existing cars and competitors. These attributes are straight-line performance, powertrain engagement, chassis engagement, lap times, cost of ownership, perceived quality, practicality and driver comfort. These eight attributes are then turned into 64 subjective targets, which are translated to a list of hundreds of objective metrics and measurements.
McLaren also uses what it calls T90 as a "time to torque" metric, basically measuring in milliseconds how long the powertrain takes to respond for a driver's request for torque. The 90 is for 90% of that torque, because it trails off after the final 10%, and McLaren says the Artura's 0.6-second T90 measurement is the quickest of any of its series-production road cars.
Taylor said McLaren hopes the Artura will "reset the expectations of the market" like the 12C did. McLaren as a whole is passionate about how closely all the different teams work together, and the Artura is the culmination of that. The goal was to create a high-performance supercar with all the convenience and benefits of a hybrid while still feeling like a McLaren, and we can't wait to drive the Artura to see if it lives up to that promise.