Chasing the Light: On the Matter of Mass Reduction

Automakers the world over are reducing vehicular mass, whether they’re making supercars that cost hundreds of thousands or pickup trucks that sell in the hundreds of thousands. Here’s a look.

McLaren & Carbon
When it comes to building cars with carbon fiber composites, there probably isn’t a company that is more obsessive about it than McLaren Automotive, which is a company that has existed since 2010 selling cars to well-heeled consumers, and which is an outgrowth of the racing activities of McLaren. It put a carbon fiber chassis in the 1981 McLaren MP4/1 race vehicle, which was followed by its introduction of the 1993 McLaren F1 (name notwithstanding, a road car). One recent example of the consequences of this composite intensity is the 570GT, which the company describes as “the most practical model ever launched by McLaren Automotive.” This is a two-seat vehicle that is powered by a twin-turbo V8 that produces 562 hp and 443 lb-ft of torque. It goes from 0 to 60 in 3.3 seconds and has a top speed of 204 mph. It is 178.3 inches long, 82.5 inches wide, 47.2 inches high, and has a wheelbase of 105.1 inches. It has a mass of just 2,796 pounds. Or, as it is reckoned in the U.K., it has a power-to-weight ratio of 416 hp per tonne (or per 2,204.6 pounds).

Jeep Goes Light for Moab
Since 1967, the Jeep faithful have been traveling to Moab, Utah—which is in eastern Utah, pretty much close to nothing (i.e., the nearest “big” city is Grand Junction, Colorado, population 61,880)—for the Easter Jeep Safari, which started existence as a one-day trail ride hosted by the Moab Chamber of Commerce, and has turned into a nine-day event.

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And for the past 52 years, the designers and engineers at Jeep in southeastern Michigan (previously in a building on Plymouth Road in Detroit, now at the FCA complex in Auburn Hills) have been creating concept Jeeps that they bring out to Moab. While this started as something of a skunkworks effort by the Jeep personnel—all of whom are engaged with the brand in ways that most companies wish their employees even had 5 percent of the commitment—with their developing things in spare moments, it has become part of the Jeep culture, creating Jeeps for Moab that have elements which may become part of production vehicles.

One of the themes that has been part of the development for the past few years has been lightening of the products. In 2011 they introduced the Jeep Wrangler “Pork Chop.” As in chopping the pork, as in eliminating the doors, top, tailgate, bumpers, carpet and sway bars.

They went to suppliers—like QMC for a prototype aluminum/carbon fiber hood; Hanson Bumpers for aluminum bumpers, and sister company Mopar for an aluminum cold-air intake kit, lightweight fender flares and more. In all, the weight of the Pork Chop Wrangler was reduced by more than 850 pounds compared to what they started with.

In 2013 for Moab they developed the Wrangler Stitch based on the Wrangler Rubicon. They took out the audio system as well as HVAC. The rear seats: gone. The front seats replaced with those used for the 2013 SRT Viper. The doors were eliminated. They cut out sections of the body. They shaved weight from the frame and axles. They replaced the hood with a carbon fiber version. They replaced the standard lower control arms, floor pan and fuel tank with aluminum versions. They reduced the size of the windshield by two inches. They replaced the soft top material with vinyl. They simply took out weight wherever possible.

And then there is the 2018 Easter Jeep Safari lightweight Wrangler, the Jeep 4SPEED, which is pretty much lightweighted so that they can get the most out of the 2.0-liter I4 turbocharged engine. The hood: carbon fiber. Fender flares: carbon fiber. The rear tub: carbon fiber . . . with perforated aluminum panels. They use perfed aluminum panels for the foot wells, as well. They shortened the length of the Wrangler by 22 inches.

Perhaps the most DIY element of the 4SPEED: they are using a welding curtain as the top of this Jeep.

2019 GMC Sierra: Light & Strong

In all of automotive, the place where there is clearly the greatest efforts to reduce mass is in the light-duty pickup segment. According to Autodata (motorintelligence.com), in 2017 there were 2,370,503 of these vehicles sold in the U.S. The whole effort was kicked off in a rather significant way when Ford went with aluminum for the skin of the 2015 F-150: sure, there had been aluminum hoods in the past, but here was a case where the body went nonferrous.

According to Ford the “high-strength, military-grade, aluminum alloys—already used in aerospace, commercial transportation, energy and many other rugged industries” contributed to a weight-savings of up to 700 pounds for the entire vehicle, although one could argue that the high strength steels used in the frame as well as changes to the powertrain helped reduce mass, too.

The latest pickup to have a notable change is the 2019 GMC Sierra Denali, which will become available with the CarbonPro. According to Duncan Aldred, vice president of Global GMC, “In 116 years of making GMC pickup trucks, our industry-first carbon fiber box is the toughest and most durable pickup box we have ever made.”

Realize that GMC has used, and will continue to use, steel for the inner panels and floor of its pickup boxes. But those opting for the CarbonPro will have those surfaces replaced with a carbon fiber composite that will reduce the weight of the box by 62 pounds.
It should be noted that they are using aluminum—for the hood, doors and tailgate—and steel—for the fenders, roof and non-CarbonPro boxes. According to GMC, they’ve managed to reduce the weight of the 2019 Sierra by up to 360 pounds compared with a 2018 model.

Lambo—Not Entirely Surprising

First of all, we have to start with something of a disclaimer, or at least something to put this exercise in exquisite lightweighting into its proper context:  “In 2017, for the seventh consecutive year, Automobili Lamborghini set a new production record, with 3,815 road cars delivered.”—Stefano Domenicali, Chairman and CEO of Automobili Lamborghini S.p.A.

That makes Tesla production seem downright productive. (And one of the things that are rarely mentioned vis-à-vis Tesla is that the Model S and the Model X are aluminum-intensive vehicles and the Model 3 features an aluminum and steel combo.)

That said, it is worth noting that when it comes to reducing mass, the people at Sant’Agata Bolognese are doing a masterful job.

Consider the Huracán Performante Spyder, which was introduced earlier this year at the Geneva Motor Show. It has a 640-hp, 5.2-liter V10 and permanent all-wheel drive. It goes from 0 to 62 mph in 3.1 seconds and has a top speed of 202 mph.

Now the Spyder is, of course, a convertible version of the Huracán Performante, which was introduced at the 2017 Geneva show. (The electro-hydraulically actuated roof, incidentally, opens in 17 seconds, which isn’t particularly blistering, speed-wise.)

The vehicle’s body is essentially aluminum over a hybrid aluminum and carbon fiber frame.

Yet there is extensive use of composite—Lamborghini’s own Forged Composite materials (this is fundamentally based on carbon fiber sheet molding compounds that contain chopped carbon fiber tows sandwiched between resin materials; Lambo developed this process along with Callaway Golf Co.—for structural applications including the front and rear spoilers, the engine cover, rear bumper and aerodynamic diffuser; these applications contribute to a mass reduction of 88 pounds compared with non-composite materials.

The car uses Aerodinamica Lamborghini Attiva (ALA), an active aero system that the company has developed. For example, there is an electric motor integrated with the front spoiler and movable flaps, contained within a carbon fiber frame. Flaps closed: high downforce; flaps open, drag is reduced. And there are ducts around the car and the rear spoiler operates analogously to the front.

One interesting aspect of the ALA components, made with the Forged Composite method, that are used is that they have a gloss surface, but they aren’t coated with color such that the components are, as put by the company, “naked.”

Ah, the Italians.