10 Best Cars with Aluminum Frames

2017 Mercedes Benz SL ROADSTER exterior profile ・ Photo by Mercedes-Benz

Fuel economy is becoming more important for manufacturers, both as a selling point and as a target to reach thanks to the regular increases in CAFE (Corporate Average Fuel Economy) standards. One of the best ways to improve fuel efficiency is to save weight, and using aluminum for a car’s frame is a sure way to shave some pounds at the scale. On this list, we will be including cars with aluminum frames as well as cars with aluminum monocoques (where the body itself forms the frame) and cars with frames built from multiple materials, but not cars with aluminum body panels over traditional steel frames (like the latest generation of Ford’s F-150). Let’s take a look at 10 best cars with aluminum frames, sorted by starting price, highest to lowest.

10) Acura NSX

Like the original Acura NSX that came out in 1990, the new model uses a significant amount of aluminum in its construction. Unlike the original, which was the first mass-produced car to use an aluminum monocoque, the new NSX uses a multi-material space frame containing aluminum and some steel (mostly around the windshield). The outer door panels, hood and roof are also made from aluminum, while the rest of the body is made of sheet molding compound, ABS plastic, and carbon fiber. The end result is an exceptionally stiff yet relatively lightweight car with a curb weight of 3,803 lbs (including the hybrid system’s motor(s) and battery). It’s not cheap, though; the NSX is the most expensive vehicle on our list of 10 cars with aluminum frames.

Photo by Acura

9) BMW i8

The BMW i8 hybrid sports car makes use of a mix of aluminum castings and aluminum sheets to form the main part of its frame (what BMW calls the Drive Module), all of which is held together using more than 800 welding seams with a total length of over 160 feet. The front and rear crash structures are also aluminum and the doors use a carbon fiber reinforced polymer (CFRP)-aluminum structure. The majority of the rest of the body and passenger cell (the Life Module) is also lightweight, made from CFRP, which is then bonded and bolted to the aluminum frame. Thanks to this attention to detail, the i8 has a curb weight of only 3,455 lbs. The all-electric i3 uses similar construction.

Photo by BMW

8) Mercedes-Benz SL-Class

The Mercedes-Benz SL-Class is a large sporty roadster with a retractable hardtop that somewhat continues the tradition started by the sleek aluminum Silver Arrows. The SL is constructed using an extrusion-intensive aluminum space frame and a mostly aluminum body (some steel is used, mainly around the windshield and in the roof, while part of the folding roof’s frame is made from magnesium, a material even lighter than aluminum). The outcome is a car that is lighter, stiffer, more economical and safer than its all-steel predecessor. Though not nearly as light as the original Silver Arrows, the SL’s curb weight is as low as 3,836 lbs depending on the model, which is particularly impressive for such a big car with its complicated roof mechanism.

Photo by Mercedes-Benz

7) Audi A8 L

Audi’s fullsize extended-wheelbase A8 L has been made largely from aluminum ever since it was first introduced overseas in 1994 and here in 1996, and the newest generation continues the trend. It features an aluminum space frame made from a combination of cast and extruded sections, as well as an aluminum body. Despite being an extra-large all-wheel drive sedan, the A8’s curb weight is as low as 4,464 lbs, depending on the model. Not only does the aluminum construction save weight, but it also makes the car stiffer, all of which leads to a quicker, more nimble and better handling car. Audi’s longtime use of aluminum in the A8 makes it a natural fit for our list of 10 cars with aluminum frames.

Photo by Audi

6) Jaguar XJ

Unlike most of the other vehicles on our list of 10 cars with aluminum frames, the fullsize Jaguar XJ uses a body-in-sheet monocoque, meaning that it is built largely like a modern steel unibody car. Jaguar started using this construction on the previous generation XJ in 2003; instead of welding the parts together as you would with steel, the pieces are held together using a combination of self-piercing rivets and high-strength epoxy structural adhesive. Thanks to all the lightweight aluminum in its construction, the XJ has a relatively svelte curb weight that starts at 3,891 lbs. It is lighter than some of its competitors, but as more and more of the competition move to lightweight materials, it doesn’t have the weight advantage it once did.

Photo by Jaguar Land Rover

5) Tesla Model S 60

The Tesla Model S is a relative lightweight, especially when you consider that it is available with three rows of seating for up to seven passengers and that it has to carry around a half ton of batteries to supply power to its electric motors. To keep the curb weight down as low as 4,323 lbs, the Model S uses a lightweight aluminum space frame and an aluminum body (though with some steel used for reinforcement in places such as the B-pillars). The aluminum sections are held together using a mix of cold-metal transfer welding, conventional spot welding, self-piercing rivets and structural adhesives. The design also allows the batteries to be mounted low in the car, lowering the center of gravity and maximizing interior space.

Photo by Tesla

4) Alfa Romeo 4C

The Alfa Romeo 4C sports car doesn’t use a full aluminum frame, but instead uses a carbon fiber monocoque tub with aluminum subframes attached front and rear. These subframes are used to hold the major mechanical components such as the engine and suspension, as well as to provide adequate crumple zones in the unfortunate event of a crash. To continue keeping the weight down, the 4C’s body is made out of sheet molding compound, which is essentially a type of fiberglass. As a result of using all this lightweight material, the Alfa has a curb weight under 2,500 lbs, which allows it to make the most of its tiny powerplant and shows that it is possible to build a relatively affordable car out of advanced materials.

Photo by Fiat Chrysler Automobiles

3) Chevrolet Corvette

The newest generation of the Chevrolet Corvette sports car uses an all-aluminum chassis that both reduces weight and increases torsional rigidity. The chassis is composed of 10 castings, 38 extrusions, 76 stampings and three hydroformed parts that are all held together with an impressive 354 spot welds, 188 Flowdrill-machined fasteners, 113 feet of structural adhesives and 37 feet of laser welds. The engine uses an aluminum block and aluminum heads, and the front and rear suspension cradles are made from hollow aluminum. Combine that with the Corvette’s composite body and you end up with a curb weight of 3,298 lbs for the coupe and only 64 lbs more for the convertible, and one of the more affordable cars on our list of 10 cars with aluminum frames.

Photo by General Motors

2) Cadillac CT6

The fullsize Cadillac CT6 is built using an aluminum-intensive architecture that incorporates 11 different materials to achieve the right mix of strength and light weight. The body structure includes 13 high-pressure aluminum castings and uses a combination of high-strength aluminum and high-strength steel to reinforce the body and create a safety cage around the car’s occupants. High-strength aluminum was also used for the rear impact bar, and a combination of high-strength aluminum and steel was used for the front and side impact zones. Everything is held together using a combination of aluminum spot welds, steel spot welds, flow drill screws, self-piercing rivets, laser welding, aluminum arc welding and hundreds of feet of structural adhesive. The lightest model uses a 4-cylinder engine and weighs in at only 3,657 lbs.

Photo by Cadillac

1) Jaguar XE

The compact Jaguar XE is the most affordable car on our list of 10 cars with aluminum frames, and if anything, that makes its high-tech construction even more impressive. Like its larger sibling, it uses a predominantly aluminum chassis and body, with the bonded and riveted metal making up 75 percent of the structure. Aluminum is also used in the suspension, including in the front knuckles and rear lower control arms. As a result of all this engineering, the lightest version has a curb weight of 3,350 lbs, while also having stiffness and rigidity superior than that of a comparable steel car. Let’s hope that the Jaguar XE encourages other automakers to build even lighter affordable cars that are economical yet still fun to drive.

Photo by Jaguar Land Rover