Body kits -- splendid cosmetics for your car

By T. Uncle

TAKE a regular BMW 318is coupe, in any color you like. Slip it through the roller door of your local body kit shop, add a generous serve of cash, and wait.

Allow approximately two days before removing, then stand in hot sun and carefully observe.

With any luck, the once (relatively) anonymous BMW will have undergone a transformation; enough to whet the appetites of anyone whose pulse is quickened by the sight of a sleek, purposeful, hunkered-down, thoroughbred motorcar.

It's the sort of thing you are more likely to see screaming past on a racetrack than slipping through the traffic, or sitting quietly at the curbside.

Body kits are just one of the forms of individual expression available to car enthusiasts.

But done properly, they are perhaps the most potent means of making something ordinary look extraordinary.

A well-designed kit is equally as effective on a Bimantara Cakra as on a Porsche 911, even if what it appears to promise may not be delivered.

The fact is that for most people, the styling statement is enough.

Body kits may have developed from hard-earned racetrack experience, but what they do -- or purport to do -- on most road cars is something entirely different.

For the racetrack, all those wings, spoilers and side skirts are there for a very specific reason, to keep the speeding mass of metal firmly on the track when aerodynamic forces might be trying to do something else.

The front spoiler, reaching down to just above tarmac height, is there to minimize the amount of air that can get under the vehicle where it will generate high pressure "lift" - something you don't want as you're approaching the fast right hander on the back straight at 220km/h-plus.

The rear spoiler or "wing" is there to catch the airflow slipping over the body and use it to generate down force, once again, to apply traction-enhancing pressure on the rear end as the car brakes or accelerates.

The side "skirts" help maintain the low-pressure zone underneath the vehicle that maintains a secure on-track stance at speed.

All these elements must be properly balanced against each other to provide stable high-speed performance.

It's obvious that too much down force at one end, either front or back, is going to have unsettling side-effects.

For the road, at the speeds most drivers travel, all this is really pretty academic: a full body kit at normal road speeds is not about to make a noticeable difference to stability.

At the same time, it is unlikely to have any detrimental effects.

At worst, it is only going to visually spoil what might have been a clean styling job by the car manufacturer, while at best it is more likely to add to, rather than detract from, overall stability.

Body kits come in various forms and are made of various materials, but the ground rules are generally straightforward when deciding which one to go for. The bottom line is that a kit sold as an accessory by the original manufacturer of the car is usually the better choice.

After-market kits are someone else's interpretation of how the styling should have been done in the first place.

These interpretations often miss the mark.

On the other hand, a really skillful, reputable body kit manufacturer can often come up with a design that not only blends with the original lines, but also adds extra spice.

Well-designed body kits, despite the realities of ordinary road use, actually do acknowledge the advisability of having balanced aerodynamics and are often the result of wind-tunnel testing.

As well as looking "right" they are also built to the same quality standards as the vehicle to which they are fitted.

A backyard, cobbled-up body kit will usually be lacking in quality and style, and will have questionable street credibility.

Materials are also a big consideration. Although early designs made wide use of fiberglass in construction of spoilers, skirts and wings, these days, the good kits are made of heat-molded polycarbonate that blends better with the flowing metal shapes of the car and is not as ready to crack and break as fiberglass.

As a general rule, it is probably best to consider the effects a cheap kit, compared to a manufacturer-endorsed kit, might have on the resale value of your car.

What works for you, will not necessarily work for everyone else.