C4 Leichtbau

In 1971 Porsche established a customer racing department for the sale of racing parts, with race driver Jurgen Barth offering support and professional advice to fellow race drivers and customer teams. Prior to this all such business had been an extension of the repair department going back to the days of the 356. This led to a growing connection between the factory repair department and the motorsports division resulting in the creation of a special request group or ‘Special Wishes’ – established in 1978 to oversee custom modifications to production series vehicles. The concept was such a success that in 1986 Porsche officially established an autonomous department to oversee all such ‘ex-works’ customization called Porsche Exclusive.




C4L-2The concept behind Porsche Exclusive also had an unusual internal counterpart whereby Porsche in the 1990’s produced limited production series cars that mimicked race car philosophy which had no homologation purpose. In this way the concept for what became known as ‘hand crafted refinement ex works’ in the 1990’s married the Exclusive department with the motorsport division. This philosophy would extend well into the new millennium with models such as the Carrera GT.




C4L-3.jpgIn retrospect the first step in this direction should have been the 1990 C4 Leichtbau. A car created for a race series that did not exist and in the end that had no real purpose – other than to be independent of the Exclusive department. The result being a highly technical no-frills race car that would have done better in a marriage with Exclusive as later models would, but instead was sold for road/race with the caveat that – in Porsche’s words – it was a ‘racing vehicle not registered for public road traffic’.


OLYMPUS DIGITAL CAMERAIts genesis was actually with Porsche’s Director of Engineering Helmutt Bott developing an AWD competition model in 1984 for rally racing, the 953, following on the 1983 2WD 954 911 SC/RS rally car and Porsche’s 4WD concept internally known as ‘C20’. By the time that car was released as a road production model, in the same year as the establishment of Porsche Exclusive, it was the venerable model 959. Bott’s vision for the production of 1,000 examples – well in excess of the 200 units required for homologation under FIA Gruppe B – went unfulfilled leaving numerous excess parts looking for a home.



C4L-5These parts were first used in the development program for the model 965 the planned follow on replacement for the 959. The economic downturn ended the 965 all wheel drive concept’s development alongside the ill fated four door model 989 – ironically both design concepts which would appear in Porsche’s future (an AWD turbo and a four door sedan). And, due to Porsche’s failing financial health and near bankruptcy, most of the rest of the 959 parts inventory was sold off.



C4L-6The remaining 959 parts not sold or previously siphoned off for development programmes would fall into the hands of Jurgen Barth. Barth, by now head of Porsche’s customer racing department, had always felt that racing programs could drive Porsche sales. And to help further establish the new 964 platform with Porsche enthusiasts he crafted a plan to build a race car series using the new platform with parts left in Weissach from these previous projects. However, in contrast to the philosophy of then FIA Gruppe B, where homolgation production need be completed within 12 months of a series start, Barth’s Carrera 4 Leichtbau, was to be built with no supporting race series in sight.



C4L-7Barth believed that this car could be brought in to the US market as a ‘race car’ for which a series could then be established. The most previous iteration of this strategy, the ‘America’ 959S, had failed in this regard. In that case U.S. regulators had determined that a car with a 17 digit VIN, air conditioning, full interior trim and leather wrapped roll bar could not actually be a ‘race car’ exempt from safety and emmission standards – and so denied its importation under the ‘race car’ exemption. Thus the plan for the C4 Leichtbau would be to issue it with a unique 6 digit only VIN and to strip it of all interior and other comforts. The car was promoted and conceived by Barth as an all wheel drive 964 ‘RS’ that would be eligible for U.S. import.


C4L-8However several factors were already conspiring to derail this car’s ultimate success from the time the plan first got traction in 1989. First, while a ‘whisper’ marketing program created customer excitement about a limited edition special purpose race car being built, there was no Porsche-only or any other race series which the car’s planned specification would actually fit. This flew in the face of prior practice where a limited series production car would have a racing counterpart that was the purpose for its creation. Further, the car was so specific in design it couldn’t practically be modified to comply with any existing race series.


Second, the design was not particularly suited to any practical application. With the 953 AWD and short-ratio gearbox it was geared for 210 kmh/130 mph in fifth gear – neither specification suitable for race track use. And the suspension was lowered as in the Carrera Cup making it unsuitable for rally racing or off road use as per the 953. Further concept design flaws like an on-the-fly manually adjustable slip bias (as in the 953 not electronically controlled front/rear axle torque split as in the 959) and lightweight aluminum roll bar were both impractical and dangerous.



c4l-10Third, internally Porsche could not distinguish how this race car would fit into the actual race car market alongside Roland Kussmaul’s (head of Porsche’s racing department) 964 Carrera Cup model. The Carrera Cup model to start racing beginning in 1990, with a planned Cup series introduction to the U.S. market in 1992. Two U.S. based Porsche-only spec series could not be justified nor supported.


c4l-11-jpgFinally, Kussmaul was already in process of implementing a race based production road version of the 964 Turbo for the U.S. market called the Turbo S2 to be built in conjunction with Porsche Car North America customer racing director Alwin Springers’ ANDIAL tuning shop. This car to homologate for the US only IMSA Supercar Championship race series – a production series whose participation had full support of Porsche CEO Arno Bohn.





Notwithstanding all of these factors, Barth determined that in fact enough cars could be sold to justify the project and set about to finalize its specifications and go to market plan. In the end 22 examples, sold directly by the factory and weighing in at a remarkably low 1,102kg, would be built from 1990-92. And although there were many gaps between orders (e.g. 007 invoice date 8/1990 – 009 invoice date 6/1991 with the final two cars built in 1992), the car was never designed for a particular race application so it was never tested and refined by Porsche beyond the initial parts amalgamation. Ultimately, as a limited production model where price was no object but with no race series and no racers to buy it, and at a stated base price of DM285,000 and a final out-the-door price of DM325,000, it became interesting only to collectors and would never see a race track in anger.