1981 Porsche 935 K4

1981 Kremer Porsche 935 K4 IMSA GTP
Chassis: 935-K4-01

During the mid-70s the Porsche factory reigned supreme with dominate performances from their rugged turbo-powered production racecars. By 1979 the factory began to switch its efforts to the new 936, 956, and 962 prototype, non-production based racing cars. This change spelt the end for the factory Porsche 935.

However, a demand still existed for the continued development of the ferocious 935. Fortunately some years earlier Porsche had given its blessing to a number of racing teams with close ties to the factory to purchase components and drivetrains, and then designed and produced their own upgraded chassis and bodywork. While these newly constructed vehicles were still generally referred to as Porsche 935s, in reality, they were entirely new designs that advanced the 935 concept to a new level of speed and sophistication. The pinnacle of these independent efforts was the overall win at the 24 Hours of Le Mans in 1979 by the Kremer 935 K3, the last production based car ever to win overall at Le Mans.

The Kremer Brothers of Cologne, Germany had enjoyed a close relationship with the factory since 1970, and were allowed to proceed independently with further development of many models of racing Porsches. They built their first variant of the 935, the K1, in 1976. By 1981, Kremer was ready to produce its fourth version of the Porsche 935, the K4, inspired by the factory Moby Dick 935 produced by Porsche in 1978. In fact, the factory gave the Kremer’s the drawings, parts, and the Moby Dick car itself on commission to build the new K4.

01 is the first of only two K4s produced, and as a result of Kremer’s constant development, bore little resemblance to an early factory 935. The K4 had evolved into a totally different vehicle, built on a full tubular chassis, with only a roof and windshield being supplied by the Porsche factory. 01 was fielded by Kremer Racing in Europe during the 1981 season, and was driven by Bob Wollek to TWO WINS and a total of six podium finishes.

John Fitzpatrick bought the car from Kremer for the 1982 IMSA season, and his team of Glen Blakely and Max Crawford immediately set to work on upgrading and modifying the car. They built a completely new body with in-door air ducts for the intercoolers, and also designed a new rear suspension and belly pans. Mechanically the K4 continued to develop the tried-and-true 935 turbo motor by using enhanced air-to-air intercoolers and ducting resulting in a 50 horsepower advantage over other 935s. With the boost fully turned up the car was capable of producing well over 800 horsepower. The result of all of this work was FIVE WINS and only one DNF in 1982. In 1983 the car raced only twice, with another win at Riverside. In 1984 the K4 was rented to Al Holbert for three races, which saw the switch to Holbert’s #14 and Lowenbrau livery.

In 1986 the K4 moved into private hands when Fitzpatrick sold it to Mike Hagen of Los Angeles, CA. It passed through a few owners over the years including actor Nicolas Cage from 1999 to 2002, and most recently Touring Auto Maintenance. During their ownership the car was taken care of by Amalfi Racing, and there are extensive maintenance records and race setup notes that come with the car.

Since arriving at Canepa the K4 has received a thorough mechanical inspection along with over 150 hours of concours detail work. With drivers such as Bob Wollek, John Fitzpatrick, David Hobbs, Derek Bell, Al Holbert and Preston Henn, this Kremer K4 represents the end of one of the greatest eras of GT racing. Here is a unique opportunity to own and drive the last in a line of stunningly successful Kremer 935 race cars.

‘The K4 was a sensational car, the fastest 935 ever, and still is.’ – John Fitzpatrick

Most recently the K4 has been featured in the August/September 2016 issue of Classic Porsche magazine.


700hp @7500rpm
536 ft/lbs @ 6100rpm
3,162 cc twin-twin turbo flat six with an aluminum block and head, dry sump lubrication, dual ignition, Kugelfisher fuel injection, Carillo connecting rods, Mahle forged pistons.
Transaxle: Porsche G30 four-speed synchromesh, with spool differential
Weight: 2,229 lbs, with a 39% front / 61% rear split
Top speed: 220 mph when fitted with the Le Mans gearing

Year: 1981
Make: Porsche
Dealer: Canepa
Canepa, headquartered in Scotts Valley, CA, is a multi-faceted automotive organization that includes Canepa, Canepa Design, Canepa Motorsports and Concept Transporters. Canepa provides exceptional automobiles to collectors worldwide, as well as performing Pebble Beach level restorations on historically important vehicles. Canepa Design is renown for expertly combining sophisticated design and superb craftsmanship in creating personalized European and American sports and luxury cars, hot rods, SUVs, and motorcycles. Canepa Design also works closely with major corporations such as Kenworth, Peterbilt, GM, Ford, and Bridgestone on concept, prototype, and production vehicles. Canepa Motorsport is the racing arm of Canepa, and is a recognized leader in mechanical and cosmetic vintage racecar restoration, preparation, and track support. Attending 6 to 8 premiere vintage races each season, their focus is on 1970's to 1980's era race cars: Can-Am, Trans-Am, IMSA, FIA, Group C, Historic NASCAR, and Historic Formula One. Concept Transporters, located in Fresno, CA, is the industry leader in "state-of-the-art" enclosed vehicle transporters, mobile showrooms, hospitality suites, and mobile emergency command centers. The company designed the industry's first aerodynamically streamlined big trucks (Kenworth) in 1983 revolutionizing big truck design and boosting fuel mileage and driver efficiency. Concept creates many different types of transport vehicles depending on the customer's specific needs. Each project is designed from the ground up creating transporters that are perfectly suited for their intended use.
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