Over the years I have had the opportunity to drive several prototype cars from various manufacturers. Some of these went on to become production cars, while others ended up tucked away in the storeroom of the marque museum. Less lucky examples went to the crusher and were never heard of again.
Pre-production like these cannot do their job properly if they are confined to the test track. In order to gain real world results they have to be tested on the same public roads where the production versions will eventually be driven. Thus, these prototypes venture out under special manufacturers test licences, their salient features camouflaged to prevent people seeing exactly what they look like.
BMW and some other manufacturers use black and white swirls as visually disruptive camouflage to break up the shape of their prototypes, while Porsche usually apply matt black film to disguise the lights and other distinctive features of their test cars, while Mercedes used white film to hide the rear half of their C-Class Coupe during testing in California.
We caught a BMW 1-Series saloon testing on the autobahn near Munich Airport earlier this year. Based on BMW’s front-wheel-drive platform this model is manufactured in BMW’s factory in China and is not sold in any other market. However, BMW need to do their testing and calibration on the German autobahns, and at their test facilities around Munich.
While these are the camouflaged prototype cars you see in spy pictures in car magazines and on Internet sites, things are not always so straightforward. Sometimes new engines and chassis are tested under an existing bodyshell or test ‘mule’ as such cars are known as in the industry.
This happens in early testing when the ‘clothes’ of a new model have not yet been finalised, but technical development has to proceed. For instance the two Porsche 918 Spyder ‘mules’ used for initial chassis testing and driving simulation were based on old Carrera GT prototypes with ballast added to simulate the weight of the batteries.
During the mid-1990s I was shown a modified Mercedes E500 (W124) with the mechanicals from the W220 S-Class that was eventually launched in 1999. And some of the mechanicals for the Maybach of 2004 were initially tested under a W140 S-Class body, which was no surprise since this car donated its basic platform for the Mercedes uber-limousine.
The test regime for any new car is very rigorous. With the increasing speed of computers more design and simulation can be carried out on the screen these days. However, while this saves time in the early development stages of a new car there is no question that real world testing, and piling on hundreds of thousands of kilometers is required to get everything right for production.
Suspension, brakes, engine start-stop, smoothness, NVH performance, heating and air-conditioning systems are tested to the nth degree. Even the way the interior trim panels act over severe road conditions in vastly differing climates is tested and re-tested until things are perfect and ready for production.
Hot weather testing takes place in Death Valley in August where the temperatures can reach 120°(49° C) in the shade, and there is no shade. Manufacturers also use South Africa and Australia although it is not as hot there.
Back in August 2004 I took part in the final hot weather test regime for the 987 Porsche Boxster in Death Valley. This four day event saw us drive two Boxsters from a hotel in Los Angeles out to Death Valley where we pushed the car and its air-conditioning to the very limits in extreme hot and dusty conditions.
As the basic shape of this second generation Boxster was not dramatically different from its predecessor Porsche simply applied some coloured masking around the lights to give them the appearance of the existing model. During our trip the only person who paid any real attention to us was the driver of an existing Boxster on the freeway coming out of LA.
With hats, cold air-conditioning, and lots of water to drink our four day test was not as taxing on the people as you would think thanks to the lack of humidity, but the trip certainly gave these calibration cars a real workout.
The two Cayenne S chase cars were loaded with spare wheels, fuel and lot of water for us to keep hydrated. I noted that the very last bottles of water from the cool boxes were consumed in the Lufthansa Cargo car park at LAX at the end of our journey, proving that the experienced logistics team had judged things very finely indeed!
The other extreme is cold weather testing, normally carried out in the northern part of Scandinavia in winter. The German car manufacturers favour Rovaniemi in Northern Finland, and have established a cold weather test centre on the frozen lakes where temperatures can drop to minus 24°F or more during a particularly hard winter.
So how many of these development cars does a car manufacturer need to cover all bases including crash testing? The answer is dozens. Even a relatively low volume supercar like the Porsche 918 Spyder, of which there are 918 production cars, ended up with two ‘mules’, 24 prototypes, and 36 pre-production cars.
Today, 28 of these working development cars are still undergoing long-term durability and reliability testing, with many having covered over 100,000 kilometres. Indeed, I have seen several camouflaged pre-production BMWs and Mercedes models of cars that are already on sale still in their original camouflage continuing their testing work on public roads.
I have also come across test cars that look so normal even an experienced car spotter would not see anything unusual about them as they passed on the street.
One such car was this classic Mercedes 190E I had the opportunity to drive back in 2009. Looking totally stock from the outside it had actually been fitted with the 2.2 litre OM646 turbo diesel as used in the C and E-Class models from this period.
With 148hp and 330Nm of torque this motor was a far cry from the 190’s original and totally gutless 75hp 2.0 litre naturally aspirated diesel. It certainly gave the relatively light and compact 190 a good turn of speed, along with levels of refinement far in advance of the original motor.
This test car covered many kilometers on the roads in Germany with calibration and monitoring equipment in the boot recording the data sought by the engineers. But because it looked like a bog standard 190 nobody was any the wiser.
It is notable that people pay far more attention to camouflaged test cars in Europe than they do in America. Out in Death Valley our presence seemed perfectly normal, and it was clear that local businesses considered our team to be valuable customers.