Taking the 'cheap' out of the small car

The idea that good things come in small packages has rarely played well with American car buyers. And who can blame them?

After all, a longstanding notion that bigger was always better, combined with gasoline at bargain prices compared with the rest of the world, led Detroit’s executives and engineers to direct their best efforts toward more profitable cars in the midsize and large classes. In the process, they sentenced their small cars to a starvation diet.

“This goes back to the domestic philosophy of ‘small cars equal small profit,”’ said Jim Hall, managing director of 2953 Analytics, an auto consulting firm. “The philosophy was that you’re going to be low-profit, so you want to convince people to buy something bigger.”

Even Henry Ford’s early investors tried to persuade him to abandon his idea for the compact, efficient Model T and instead concentrate on big 6-cylinder touring cars because that’s where the money was.

Though Ford prospered with the Model T, his business plan later changed, and in the postwar years hulking, powerful American cars prevailed.

There’s no getting around the basic mechanics that make longer, wider, heavier cars feel comfortable on the road and their 6- and 8-cylinder engines inherently silky and quiet running.

“Generally, the lighter and shorter the car, and the shorter its wheelbase, the greater the challenge in your overall refinement options,” said Jim Federico, General Motors’ global chief engineer for small cars.

He noted that while a smaller car’s lighter weight can benefit fuel economy, it may also reduce the pleasure of traveling in it.

“First, mass is actually your friend for reducing NVH,” he said, using the engineer’s shorthand for noise, vibration and harshness. “So our approaches to designing in refinement on a 3,100-pound Cruze and a 2,200-pound Spark will have many similarities and some differences.”

Even the profile and proportions of the bodies are factors: A long car typically manages airflow at the rear more smoothly, while a design that has been truncated abruptly at the rear generates turbulence at speed.

“The shorter the vehicle, the more difficulty engineers have in making aerodynamics work in favor of fuel economy, as well as interior noise,” Federico said. “Cars like the Spark create an expectation, because of their small size, that they have superhigh highway fuel economy. But in reality they have the aerodynamics of a brick.”

The refinements that helped turn big cars into Detroit’s profit centers were mostly absent when fuel efficiency became a selling point in the 1970s and '80s and a wave of new small cars arrived in showrooms.

Remember the Ford Pinto and Escort? Datsun F10? Dodge Shadow? The Chevrolet Chevette and Citation? They may have been cheap to buy, but there was little joy in driving them. These and other buzzy underachievers – often called penalty boxes and worse by owners – set a low bar for the small-car genre in the United States.

The picture is much brighter today. Small cars have the benefit of years of development, and US buyers demand greater levels of polish. Consider how far removed a modern compact like the European-bred Ford Fiesta has advanced from efforts of four decades ago like the troubled Pinto.

Some credit for this trend belongs to the vehicles that came from Japan and Europe, where gasoline has long been expensive and multivehicle families are far less common. There, the reference standard for small cars is on another plane entirely.

Delightfully light-to-the-touch controls and 4-cylinder engines with electric-motor smoothness became hallmarks of cars like the Honda Civic, which elevated refinement in a mainstream small car to an art form.

Buyers in the United States and Europe generally have different expectations about vehicle refinement, particularly in regard to the powertrain. Because manual transmissions are far more prevalent in Europe, for example, drivers are more used to the sound, vibrations and comfort levels associated with shifting gears manually.

The task of designing-in greater levels of refinement is affected by size. Today’s small cars actually span three main segments in the global vehicle market. The tiny A-segment cars include the Chevy Spark and Smart Fortwo. They’re extremely short and very light.
Slightly larger are-segment cars like the Ford Fiesta and Chevy Sonic. The A- and B-cars are known as subcompacts.

The compact C-segment are the largest of the small cars. Examples include the Toyota Corolla, a perennial sales leader, as well as the Ford Focus, Chevy Cruze, Hyundai Elantra, Honda Civic and Volkswagen’s Golf and Jetta.

Chevrolet’s entries in all three segments highlight the small-car dimensional differences that can limit their relative refinement. The Spark is just 145 inches long, has a 93.5-inch wheelbase (the distance between axles) and weighs about 2,240 pounds.

The B-segment Sonic is 18 inches longer than the Spark with a wheelbase nearly six inches longer; the Sonic is also almost 500 pounds heavier. The C-segment Cruze is yet another 18 inches longer than the Sonic, with a wheelbase more than six inches longer; the Cruze weighs almost 400 more pounds more than the Sonic.

Mike Merlo is chief engineer of the 2012 Dodge Dart, which is based on the well-regarded Alfa Romeo Giulietta platform developed by Chrysler’s parent, Fiat.

Merlo’s counterparts in Italy define “vehicle refinement” differently from the American engineers.

“To them, refinement means a ‘European feel’ of the car,” he said. “They spend a lot of time on seat comfort and its relation to the driving position, and maybe not as much time as we do on road isolation characteristics, because their roads are generally in much better condition than ours.”

European car owners also favor three-season tires that have exemplary ride and handling characteristics in spring, summer and fall. When winter comes, they install tires with specific winter grip and performance; Americans typically mount all-season tires for year-round use.

A suspension calibration can involve changing the rubber bushings at the connecting points between the suspension and the body. The bushings are rated according to their specific hardness; different bushings give firmer handling, a more compliant ride or a combination of both. Calibration can also involve the selection of alternate wheels and tires, and upgrading to sophisticated, and more expensive, suspension dampers.

Merlo noted two important lessons, shared by the members of his Chrysler team and their Fiat counterparts, that brought a higher level of refinement to the new Dart. One was a type of door construction commonly used in Europe that features advanced noise-sealing techniques.

The other was Chrysler’s unusually high standards for the stiffness of the car’s body – the torsional bending measurement. Chrysler’s requirement surprised the Fiat engineers, but the extra rigidity made it possible to build the larger Dart from the smaller foundation of the Alfa.

“These really helped us end up with a cabin that’s very quiet,” Merlo said. “Because the body is stiff, it allows us a lot of flexibility to have both a softer-riding car when we want it to be soft and a firmer-riding car when we want it to have outstanding chassis dynamics.”

With U.S. small-car sales up 14 percent in the last decade, automakers are increasingly devoting major design and engineering resources to their development. Extensive computer analysis of body construction and materials, noise and vibration sources and driving dynamics is done in the early stages of vehicle design before any metal parts are made.

The goal is to identify the sources within the vehicle that cause unpleasant acoustics, sloppy control or poor driving dynamics – and reduce or eliminate them, rather than devising expensive fixes aimed at masking them.

Engineers can select from a deep box of technologies aimed at vehicle refinement, including sound-damping materials behind the dash panel, under the floor and in the headliner; thick door seals and laminated acoustic glass.

But the state of the art in executing a great small car is in knowing how to make the vehicle refined in the right places – making a steel bulkhead a fraction of a millimeter thicker, or using an adhesive to join two parts.

“The key is to thoroughly understand the vehicle’s dynamics and NVH sources up front,” Federico said.

“To an increasing number of American buyers, small cars are no longer base cars,” said Hall, whose experience as a magazine journalist exposed him to many of the worst small cars of past years.

“They want the same things they have in their larger cars, just in a smaller size. They don’t need the space, and they’re a generation who are more open to small cars than their parents were.”