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The story of our Porsche K4

29. Jun 2020 
by John Fitzpatrick
4739 views

Our Porsche K4, by John Fitzpatrick

The K4 was based on the aluminium tubed framed so called “Moby Dick” that Porsche built for the 1978 World Championship season.

Both Joest and Kremer built tube framed cars based on drawings from the Porsche factory. The K4 that I owned and raced was initially raced by Bob Wollek in the DTM and brought over to my race workshop in San Diego in the US during the winter of 81/82.

I had won the IMSA Championship for Dick Barbour in a 935 in 1980, but Dick pulled out of racing at the the end of the 1980 season and I started my own team, initially with a 935 K3. I had some successes and when IMSA announced they were bringing in a GTP class, similar to the European Group C, we initially decided to buy the recently introduced 956.

However IMSA decided they didn’t want to risk another Porsche domination and banned the 956, citing it as dangerous as the drivers feet were slightly ahead of the centre line of the front wheels. 

My American sponsor at the time was only interested in backing us if we raced a Porsche so we decided to buy a K4 that Kremer had raced in the German series in 1982.

We brought the car back to San Diego and my Team, headed up by Max Crawford, set about modifying the car to compete against the GTP IMSA cars of March and Lola.

We stripped the car down to the bare frame and lightened the tube frame chassis whilst strengthening it at the same time to improve its rigidity. Key to the performance improvement was replacing the large single intercooler with twin intercoolers from the Porsche 908, a separate intercooler for each bank of cylinders.

We were able to run a higher turbo boost pressure of 1.7 bar which gave us a power output of well over 750 hp. Several modifications were done to the bodywork including fairing in the doors and improving the ducting to the oil and air to air intercoolers.

After a slow start in the first 2 races the K4 became a winner and beat the early GTP cars frequently. However, Porsche were not to be outdone and developed an IMSA legal version of the 956, namely the 962, which went on to dominate IMSA in the hands of Al Holbert and Derek Bell.

My sponsor in the US was not happy about the IMSA attitude and we closed the workshop in San Diego and relocated to Silverstone where we ran a Team of 956’s in the World Championship and were successful in beating the factory team at the Bands Hatch 6 hour race. The K4 was an end of an era of production based cars in the World Championship.

Source: John Fitzpatrick

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