2007 Hyundai Elantra

About 30 years ago, Hyundai was best known for assembling Ford’s Cortina and Granada from CKD kits, and building its first home-grown design, the forgettable Pony. Within recent memory its vehicles were odd little blobs at the bottom of the market, or a car for those for whom finishing atop the J.D. Power list was less important than getting a new car for used car money. Now, however, Hyundai is building vehicles that keep engineers at other OEMs up at night. The latest is the Elantra sedan.

“Our R&D team is maturing to the point that our capabilities in this area are world class,” claims John Krafcik, v.p. Product Development and Strategic Planning, Hyundai Motor America, “especially when you consider that our guys couldn’t use aluminum or exotic materials in this price class, and that the XD–the third generation Elantra that is just being replaced–was designed 10 years ago.” According to Krafcik, this means the Hyundai engineers “have to be smarter and use the CAE tools better” than the competition. He points to the fact that the 2007 Elantra has an all-steel suspension, all-steel monocoque body (which includes some high-strength steel), an iron block 2.0-liter inline four-cylinder engine, and the biggest interior volume in its class (112.1-ft3, or 97.9 ft3 of passenger space and 14.2 ft3 of trunk space), and weighs 2,723 lb.—60 lb. less than the XD Elantra. Only the Toyota Corolla, Honda Civic, and Ford Focus are lighter, but their interior volumes are anywhere from 3.2 ft3 to 8.2 ft3 smaller–and they have fewer standard features. 

The engineers spend time examining each intersection and load path for the greatest efficiency, and cross-referencing this with the number, spacing, and type of welds. This allows them to specify the right steel grade and thickness along each beam and section, and draw from a growing library of basic joints as their starting point. These are then massaged to meet the needs of the particular structure, or turned into a new joint design for the library. The result is a body Hyundai claims is 49% stiffer than the outgoing model, and 9% stiffer than the current Toyota Corolla. This makes it much more tunable, a characteristic that Wendell Collins, Jr., senior engineer, Vehicle Development Chassis & Brake, Hyundai-Kia America, says he used to his advantage.

“The initial chassis tuning wasn’t at the level we wanted it to be for the North American market,” says Collins. “The steering was too light and the shocks didn’t have the compression and rebound characteristics we wanted for this car.” The University of Dayton grad, who worked a combined 22 years in chassis development at both Delphi and GM, spent days developing the car at Hyundai’s Mesa, AZ, proving grounds and on roads driven by the average buyer. “The car had to meet the ‘90% solution’ [satisfy the needs of 90% of the buyers on 90% of the roads they drive 90% of the time], but it also had to handle that other 10% well enough that the car didn’t become a handful or lose its character.” Collins and his team created unique valving for the gas-charged twin-tube dampers, worked with TRW to tune the column-drive variable electric power steering system (read Prevailing Technology), increased the size of the anti-roll bars (23-mm front/17-mm rear, an increase of 5 mm on the rear bar), and altered the feel of the four-wheel disc brakes (10.8-in. front/10.3-in. rear with four-wheel ABS and electronic brake-force distribution). “The suspension [MacPherson struts in front and a multi-link independent rear] went through at least two tuning iterations from June 2005 before it was signed off in April of 2006,” says Collins. Unlike many of its competitors, the GLS, SE, and Limited models all have the same suspension tuning. “Giving the customer anything but your best across-the-board is a waste of time, money, and effort,” says Krafcik.

A lot of effort, however, was spent on revising Hyundai’s 2.0-liter Beta four-cylinder and meeting an internal goal of increasing the XM Elantra’s overall fuel economy by 3 mpg to 4 mpg. “The architecture of the Beta motor is the same,” says Krafcik, “but literally hundreds of improvements have been made to the engine.” The Beta retains an iron block and aluminum DOHC head with continuous variable valve timing, and is available either in ULEV (Federal) or PZEV (California) states of tune. Hyundai engineers lowered the idle rpm (+0.24 mpg), altered the engine control algorithms (+0.56), and reduced internal friction (+0.24). Nevertheless, output is 138 hp @ 6,000/136 lb-ft @ 4,600 rpm for the ULEV motor, 132 hp @ 6,000/133 lb-ft @ 4,600 rpm for the PZEV version, and is sent to either a carryover five-speed manual or revised four-speed automatic transmission (+0.88). The remaining fuel efficiency improvements came from keeping vehicle weight in check (+0.44), using electric power steering (+0.68), reducing tire rolling resistance (+0.64) and improving driveline efficiency (+0.32). No matter which gearbox is chosen, the Elantra is EPA rated at 28 city/36 highway.

The news car is larger (2.2-in. taller and 2.0-in. wider than before), with a driver’s seat that is 1.8-in. higher, and just as much effort was expended on the interior as was spent elsewhere. A two-tone (shades of beige and gray) instrument panel with an integral dash-top storage bin, blue backlit gauges, and a leather-wrapped steering wheel are standard, but are not free. “The blue lighting brings with it a cost of about $50 per vehicle,” says Krafcik. “That is a ballpark full amortized estimate that includes the cost of going from all-green lighting to all-blue lighting for a full interior, and can vary significantly depending on the number of LEDs and other factors,” he says. Hyundai also uses in-color slush-molded hard plastic that is sealed with a coat of paint to add depth and reduce gloss for the instrument panel, and tops it off with a surprisingly upscale thick leather steering wheel with bright accents mimicking those on the instrument panel. “We spent the money on these items because these are the areas that the customer said were important to them,” he says. It’s just one more reason for the folks at other OEMs to lay awake at night wondering what Hyundai will do next.