“SUPERCAR” is a title without official qualifications, a mark of achievement awarded by popular acclaim, not based on codified statutes.
Simply put, we know one when we see one.

Or, we used to. Lately, admission to the pantheon inhabited by the likes of the Ferrari Enzo or the Lamborghini Murciélago has become a squishy affair. A top speed beyond 200 miles per hour, once the sole province of tightly wound 12-cylinder exotics, is available in places as prosaic as a Chevy showroom.

Now, membership seems to hinge as much on exclusivity — annual production no greater than the hundreds, ideally — to make the case for supercar eligibility. A price tag that crowds half a million dollars would clinch the deal. The Bugatti Veyron, with more than 1,000 horsepower and a price that sneaks up on $2 million, easily qualifies.

Then how to classify the 2012 McLaren MP4-12C, a two-seat projectile with a window sticker of $231,400 whose 592-horsepower twin-turbo V-8 will launch it to a terminal velocity of 205 m.p.h.? McLaren, long a dominant force in Formula One racing, says the 12C will outperform competitors widely acknowledged as supercars: the blast to 120 m.p.h. takes but nine seconds.

On the other hand, ownership will not be restricted to a privileged few. Production this year is projected at 1,000 cars, with more than double that number for 2012, so there’s the chance this made-in-England upstart will not embody the snob appeal of alternatives from Continental Europe.

Giving the McLaren some supercar bona fides is a distinction that the MP4-12C shares only with card-carrying supercars: a chassis made of carbon-fiber composites. Long proven on the Formula One circuit and widely accepted in aerospace roles, the carbon cloth, formed of bundled black strands and used instead of stamped metal panels, imbues the McLaren not only with high strength at low weight but also the allure of the exotic.

Still, what really makes the McLaren important to the broader automaking industry is its price: at about half the cost of any previous effort, it is the cheapest car yet with a carbon chassis.

Indeed, the advances McLaren has made toward democratizing carbon fiber could well trickle down into the family sedans of the future. As a structural material, it is carbon fiber’s tortuous production process that has sequestered it in the vehicular stratosphere. Yet its potential to revolutionize passenger cars both for safety (it is incredibly strong) and for fuel efficiency (its strength enables reduced weight) has made it a subject of research at carmakers around the world.

McLaren surely has the credentials to make this leap. In 1981 its racing team was the first to use a carbon-fiber monocoque in Formula One. The first road car to use a carbon fiber structure was the three-seat McLaren F1 of 1992, and a decade later the company began a run that produced some 2,150 Mercedes SLR McLarens over a half-dozen years.

The advances in carbon-fiber fabrication, improving from the 3,000 hours needed to make the million-dollar F1 road car’s chassis to the 400 hours required for each SLR, were remarkable. But the process needed further streamlining to make possible higher volume production of less expensive cars like the 12C.

Such a course of technology development is a handy wink-wink long used by automakers to justify spending millions on racing. Advances like paddle shifters and the dual clutch transmission have migrated to the streets from Ferrari’s Formula One cars and Porsche’s endurance racers, and we are better off for it.

McLaren’s racing team, of course, really had no recipient for its innovations, at least until McLaren Automotive was formed and the MP4-12C came along.

Formula One teams are forever in search of an edge; that part of McLaren’s tradition figured strongly into the development of a method to produce the 12C’s chassis more efficiently. Racecar structures — the “tub” that encloses the driver, with attachment points front and rear for the suspension and powertrain — are built up from sheets of woven carbon-fiber cloth. The cloth, impregnated with epoxy resin, is laid by hand into a mold and cured in a special oven, called an autoclave, for hours.

The process used to make the 12C chassis, which the company calls a MonoCell, has been radically abbreviated. Working with Carbo Tech of Austria, the engineers adapted a technology known as resin transfer molding to speed production. The carbon-fiber cloth is loaded into a mold, where both heat and pressure are applied and an epoxy resin is injected.