OK, we'll admit it—there was a lot of excitement in the office leading up to our time with the McLaren 650S Spider. And why not? This is a proper carbon fiber supercar, built in the same factory as one of the most successful and storied Formula 1 teams. It's from the same company that built the legendary McLaren F1, a 240mph three-seater that to many—including yours truly—remains the greatest car ever to turn a wheel. We were the first publication to get any time with McLaren's latest press car, fresh off a boat from the UK with a mere 350 miles on the digital odometer. The following few days were extremely memorable, and the Volcano Red convertible earned its position as our favorite car of 2015.

McLaren has been building road cars for more than 20 years now. We shan't bore you too much with talk of the F1, save to say it was the first completely carbon fiber road car, and it came with a fantastic 6L BMW V12 engine, three seats, and a top speed that wasn't equalled until the Bugatti Veyron appeared with another 400hp. Sadly, just over 100 were ever built (the plan was to make 300), and today you'll need quite a lot of money to buy one. Recently, one sold for $12 million—not bad for a car that was selling for less than list price in the late 1990s.

The F1 was followed by the McLaren Mercedes SLR, a joint venture with the company that supplied McLaren with its Formula 1 team engines for many years. A contemporary of the Ferrari Enzo and Carrera GT, the McMerc remains a little unloved, possibly thanks to the automatic gearbox and SL-like looks. The general feeling is that the car is less a McLaren than a Mercedes, which means it might be an under-appreciated bargain in the making should early 21st century supercars be your thing. But even if the design of the car suggested Stuttgart, it was in fact built in McLaren's state-of-the-art factory in Woking about 40 miles from London.

No such accusations could be leveled at the cars which have succeeded the SLR. McLaren uses a common platform for the different series of cars in its range, which use variations of the same carbon fiber chassis and turbocharged 3.8L V8. First out of the gates was the MP4-12C (later shortened to just 12C) in 2011. This was the first of the Super Series cars, and the 650S Spider is one of the latest evolutions in this series. (Above the Super Series is the Ultimate Series P1, and below is the new entry-level Sports Series 570S).

Design

Elle Cayabyab Gitlin

Elle Cayabyab Gitlin



Elle Cayabyab Gitlin

Elle Cayabyab Gitlin

Elle Cayabyab Gitlin

Elle Cayabyab Gitlin

Elle Cayabyab Gitlin

Specs at a glance: 2016 McLaren 650S Spider Body type 2-door convertible Layout Mid-engine, rear-wheel drive Powerplant 3.8L twin-turbocharged V8 Transmission Seven-speed Seamless Shift Gearbox Dual Clutch Automatic Horsepower 641 bhp @ 7250 rpm Torque 500 lb-ft @ 6000 rpm Steering Variable-ratio electrohydraulic power steering Double wishbones front and rear, "ProActive Chassis Control" interconnected hydraulic dampers Tires Pirelli P Zero Corsa

Front: 235/35 R19

Rear: 305/30 R20 Top speed 204mph/329km/h Fuel economy (City/highway/combined) 16 mpg/22 mpg/18 mpg Weight (DIN) 3,236 lb (1,468 kg) Wheelbase 105.1 in (2,670 mm) Dimensions 177.6 in (4,512 mm) x 74.6 in (1,895 mm) x 47.4 in (1,203 mm) (LWH) Base price $284,500 Price as tested $317,720 Options added Contrast stitching on dashboard, Carbon fiber sill panels with brand logo, Volcano Red paint, Soft close doors, Sports exhaust, Forged sport wheels - stealth finish, Enhanced technology pack, Stealth Pack, Lithium-ion battery, Carbon fiber interior upgrade, Carbon fiber mirror casings,Carbon fiber rear bumper,Carbon fiber front splitter,Carbon fiber door blades, Branded floor mats, Full leather interior, Black brake calipers, Tire pressure monitoring system.

The centerpiece of the Super Series chassis is called the MonoCell. The MonoCells are made for McLaren by an Austrian company called Mubea Carbo Tech through a process called resin transfer molding. This is much more automated than the almost-handmade "pre-preg" carbon fiber used in the F1 and SLR road cars or the racing team's Formula 1 cars, and in total it takes about four hours per tub. The MonoCell weighs just 165 lbs (75kg) yet gives the car its strength and stability. And because McLaren designed the MonoCell with coupes and convertibles in mind, the Spider loses none of the stiffness of a closed-roof car. What's more, the powered retractable roof only adds an extra 88 lbs (40kg) to the car's dry weight—3,020 lbs (1,370kg)—in relation to the 650S coupe.

Bonded to the MonoCell at the front and back are aluminum subframes onto which the engine and suspension are mounted. The body panels that cover all of this are mostly carbon fiber as well. On our test car, many of these were unpainted, showing off the pre-preg weave, which was beautifully aligned down the center of the front splitter and rear bumper (the unpainted carbon bits also save a few lbs here and there). The 650S' shape is an evolution of the 12C's, which came in for a little (undeserved in our opinion) criticism for being too anodyne.

As part of the redesign, McLaren now draws in a lot of elements from the P1. The front splitter is larger, as are the side intakes that feed the engine bay with cool air. McLaren say that the 650S has the same drag coefficient as the 12C (0.36, which is a little higher than most of its rivals), but the new shape produces much more downforce—24 percent more at 150mph (km/h) apparently. The car also features some active aerodynamics courtesy of the movable rear wing, which also pops up as an air brake when you need to slow down in a hurry.

The two-piece roof is electrically operated, stowing itself between the cabin and engine in 17 seconds at speeds of up to 30mph (km/h). Roof-up, the car looks very similar to the 650S coupe. With the roof down, the appearance from the side is more like a targa, thanks to the large buttresses behind each seat. These maintain the profile of the car and also double up as rollover protection.

One thing you do lose out on compared to the coupe is your view of the engine. Instead of a large rear window that exposes the engine bay to onlookers, much of the 650S Spider's engine is covered by the cubby into which the roof retracts. But what an engine it is, having now won its class in the International Engine of the Year competition three years running. It's a twin-turbocharged 3.8L V8, made from aluminum and designed from scratch for McLaren by British engineering firm Ricardo. Different versions of the M838T are used in all of McLaren's road cars—including a hybrid version in the P1—and surprisingly it's actually a relatively simple design.

There's no direct-injection for example, but it does have a dry sump (which keeps the height of the engine block down and prevents oil starvation during cornering) and a flat-plane crankshaft (meaning high revs and a high specific output compared to something like a short block V8). For the 650S, the engine got new pistons, cylinder heads, and exhaust valves. Throttle mapping and valve timing was also tweaked compared to the 12C, which helped drop CO2 emissions and sharpen throttle response. Forced-induction engines will always suffer in comparison to naturally aspirated ones when it comes to that last attribute, but the realities of climate change and 21st century emissions regulations mean turbochargers are becoming the norm.

The development of the engine from 12C to 650S also benefited from lessons learned on the P1. The goal, according to McLaren Director of Product Development Mark Vinnels, was to replicate the linear power delivery of the hybrid car (which fills in gaps in the torque curve with the electric motor). "We wanted to replicate this experience on the McLaren 650S as closely as possible," he told Ars. The new throttle mapping was designed "to give an instant feeling of response to any throttle input rather than a sudden boost of turbo torque. It’s more progressive. You also need to push the pedal less to get action."

Jonathan Gitlin

Elle Cayabyab Gitlin

McLaren

McLaren

McLaren

McLaren

McLaren

The end result is an engine that revs freely to 8,500rpm, and you're encouraged to use those revs, too. Most turbocharged engines have relatively flat torque curves, so there's little point running them to the upper rev range, but the 650S' torque curve has been tuned to rise from 3,000rpm. The headline figures are 641hp (478kW or 650PS, hence the name)—at 7,250rpm, 500lb-ft (678Nm) at 6,000rpm. As is de rigueur these days, extremely clever electronics govern the car's behavior, with different modes for the powertrain and suspension (normal, sport, track, and winter), and they're independently selectable (so you can have the suspension in normal and the powertrain in track, for example).

That power gets channeled to the rear wheels through a seven-speed dual-clutch gearbox (Seamless Shift Gearbox or SSG in McLaren-speak). This has also evolved from the 12C, although the changes involved new code rather than mechanical bits. There's no limited slip differential, though. Instead, the car uses an open diff and a brake steer system, which the company originally developed for its 1997 MP4-12 Formula 1 car. That system—which was quickly banned—used a second brake pedal to brake the inside rear wheel in a corner.

That system was fine for Mika Hakkinen and David Coulthard, but two brake pedals might be a bit much for the rest of us. In the 650S, it's all handled by the computer that governs the car's suspension. The ProActive Chassis Control suspension on the 650S is rather interesting in its own right. There are double wishbones at all four corners, but it's the dampers where things start to get complicated.

It's not a magnetorheological system like the Corvette Z06 or Lamborghini Hurácan; instead McLaren uses twin-chamber hydraulic dampers (using the same fluid as the power steering and driven by the same electric pump). Each corner is independently controlled, and the bump damping is constantly varied based on road conditions via adjustable actuator valves. However, it's the hydraulic roll control where things get fascinating. Rather than use antiroll bars, the dampers are connected to each other (again similar to a system that was used in Formula 1 until it got banned).

The dampers' compression chambers are connected to the rebound chambers on the opposite side (so front-left compression to front-right rebound and so on), but the compression chambers on each side are also connected (front-left to rear-left, etc). With all four corners linked, the car exploits the fact that fluids will flow from high to low pressure. For example, when a car is cornering, weight transfer induces it to roll (in a right-hand bend the car will roll to the left), so the damper on the outside of the turn will compress as the inside damper extends. Since they're cross-linked here, they oppose each other, which controls the amount the car rolls.

Accumulators control the amount of hydraulic fluid flow from damper to damper. As the fluid enters the accumulator it meets a pocket of gas separated from it by a diaphragm, and it's this base pressure in the accumulator between the gas and fluid that determines how much roll stiffness there is. The pressure increases in each successive handling mode (normal, sport, track), with the highest base pressure and therefore the lowest possible roll in track. The end result is high roll stiffness, but low stiffness in other conditions (when the car is pitching forward under braking or backwards when accelerating), all at levels chosen by the driver.

Listing image by Elle Cayabyab Gitlin