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Constructor Porsche AG
Chassis Production 911 steel with aluminium tube roll-cage and strengthening.
Body Glass fibre or polyurethane(Kevlar on K3) body parts.
Suspension McPherson strut at front, semi-trailing arms rear, coil springs. Lower wishbones, longitudinal torsion bars, Bilstein shock absorbers, anti-roll bar
Gearbox Porsche synchromesh 4speed with solid final drive.
Wheelbase : 2271 or 2273mm
Front track 1502mm or 1630mm(935L)
Rear track 1560mm or 1575mm
Engine Flat 6, air-cooled 2856cm3 to 3211cm3. Fuel injection via Bosch plunger pump. Single or twin KKK turbocharger.

The Porsche factory has always been a key factor of the racing scene, and many different models from the German make have yet shone on the IMSA circuit. From the Porsche 911 which began its career in 1971 to the Porsche Carrera, in many flavors, to the Porsche 934. The 935 was not a revolution in itself but it featured many of the components needed to win in GT racing. The cars were not allowed to run before the end of 1977. Fearing their domination, John Bishop did not want the Porsche Turbos to run from the beginning, which had caused a clash between Porsche Motorsport's Jo Hoppen, and him. But it would not last for long. The IMSA President soon realized that it would bring harm to his organisation, so at the end of 1976, Porsche 934s were allowed to enter the fray. Customers had purchased the turbo versions of the Carrera, but the 935 was already entered by the works team. The car was powered by a 2,8L flat 6 fitted with a single KKK turbocharger. (technical) The 1976 had been, except for Kremer who had his own 935, exclusively run by the Works team. As soon as 1977, customer cars were offered to any racer willing to fight for the overall. For 1977, IMSA did not accept, except on one occasion, the Porsche 935s. The Mid Ohio 3Hour would be the first race ever to feature Porsche 935s. The cars were entered by Peter Gregg, Jim Busby and Vasek Polak and once again Peter Gregg who won the race. It was the first win of a 935 in the US and many were to come by. Cars were powered by single turbo versions of the 2,8L engine producing 590hp, but it is commonly known that they probably had more. Their weight was given for 970kg. They had the famous slant nose and massive fenders. The 1978 rules were crafted and allowed the German cars to enter, and John Bishop's major sponsor had pressured him to do so. Two options were offered to the customers : update the 934s that many had purchased the previous year or purchase a brand new one. The 1978 cars were slightly different from the 1977 version, and sported a 3,0L twin turbo with brand new rear fenders. A new twin turbocharged engine designated Typ 930/78 was the major difference with the previous year car. It was derived from the unit used in 1977 by the Works team, it was bored out by a further 2.2mm taking overall displacement from 2856 to 2994cc. Two KKK K-27 turbos were installed (boost normally being set at 1.45bar) and there were also the latest water-to-air intercoolers, output rising to 675bhp at 8000rpm. The 1978 customer cars were equipped with ground effect-style running boards and removable rear fenders. Here are the teams who purchased 1978 935s.

Cars were identical to the Factory 1976 cars. Basic drive train, four-speed gearbox and fhe 2,9L turbo engine. The water-based cooler system had been improved for a better efficiency. It had been moved to the rear of the engine comparrment. The rear bulkhead had been moved forward by 200mm. The floor pan of the passenger compartment had been raised by three inches. The 935.77 roof was flatter than that of the other 911 based cars. This was meant to improve aerodynamics. The rear wing could be more efficient. The front suspension featured improved geometry and lighter McPherson-type strut units. The adjustable anti-roll bar was moved to the front while the rear suspension remained unchanged. The engine received a twin KKK turbocharger, giving a slight power increase, but reducing turbo lag. The tail section was a new piece that fitted over the original body and rear window. The 935.78 sported an inverted transmission, which proved quite effective on the Works car. Customer cars were powered by twin turbo versions of the powerplant. Peter Gregg dominated the 1978 Championship with a twin turbo Porsche 935. It was immaculately prepared by Brumos Racing who had achieved a high degree of professionalism. He won nine races (including the 24 Hours of Daytona race with the Gelo Racing entry) out of fourteen and captured the Championship with 183 points, to Bill Whittington 108!

For 1979, In order to counterbalance the Porsche domination, John Bishop decided to add a 40kg additional weight to the twin-turbo cars. Porsche did react to this proposal in offering his customers single turbo versions of its 935. This alternative would allow those cars to carry less weight. Some of the regular entrants, including Peter Gregg, chose this option. In fact, the best option seemed to be using a 3,2L single turbo engine. It would be the last series of Porsche 935s built by Weissach. Seven of them were built, all of which were originally delivered to the USA equipped with single turbo Typ 930/79 engines. The displacement rose to 3124cc, compression being upped from 6.5 to 7.0:1. A solitary KKK K-36 turbocharger was installed along with a ‘Moby Dick’-style inverted transmission and brakes from the works 935 ’78 too. Pumping out 680bhp at 8000rpm and weighing at just 1025kg, there was little to touch the 935 ’79 although some teams did revert to a twin turbo set-up during the course of the year. The 1979 season would be a new domination for Peter Gregg who won overall with his single turbo Porsche 935. He won eight races and totalled 205 points at the finish. Second was Charles Mendez who had consistent finishes, and one victory in the Paul Revere Daytona race, and earned 132 points. Additionally, the Whittington Bros had begun to compaign their own version of the Kremer K3 body. The car sported the aerodynamic features that were typical from the German shop. They had just bought their ride for the 24 Hours of Le Mans and won the great Endurance race. They won the 6 Hours of Riverside with a more classical 935, along with Klaus Ludwig. They won the Daytona Finale with a pair of K3s.

The following year, the K3 bodywork would become the new standard for the turbocharged German cars, and every team would own his K3. However, the rules for 1979 were modified in order to slow them. Therefore, single turbo versions of the 935 were introduced, with less weight to carry. Peter Gregg became the 1979 Champion with such a car. However, in Europe, the Kremer brothers had introduced the K3, a Porsche 935 fitted with a more radical bodywork. A similar car won the pestigious 24 Hours of Le Mans with Klaus Ludwig driving. He was partnered by brothers Bill and Don Whittington. The two brothers purchased the car and introduced it in the middle of the 1979 season. This car featured a flatter fiberglass roof as well as the deep wing fences to better control the air flow over them. One of the biggest improvement was the use of an air to air intercooler, keeping temperatures at a lower level. The power was more usable and for longer periods. An overall stiffening of the structure, achieved by aluminium tubing from the rollcage to each of the suspension points. Engine removal was much easier, and this was due to the rear crossmember, now replaced by two aluminium tubes bolted in place. A 3,2L engine was used in shorter events and it could give 800hp. Fences ran the length of the front and rear fenders. The air could flow over the top of the car to the rear intakes and spoilers. The rear window was covered with a roof extension containing another window and serving as a mount for the spoiler.

1980 was the year the Porsche 935K3 became prominent. The aerodynamic package was quite different from the works Porsche 935 look, and they had developed their own idea of the beast. The wing fences were theirs, and most important was their way to reinstall an air to air intercooler. This helped the car keep the air temperatures lower for greater period of times. Many of the race teams willing to fight for the win wanted their own K3. They did it while converting their personal car to this specification or purchasing a brand new one. However, some teams wanted to test the personal idea they had of the successful Porsche Turbo. It was the case for Bayside Disposal Racing or Momo Corse who had their own version of the Porsche 935. Dick Barbour had his own set of cars and hired John Fitzpatrick as his first driver. A good choice indeed as the Englishman swept the 1980 Championship and beat everybody, including the 1979 Champion Peter Gregg. At the beginning of 1980, Interscope Racing had a brand new car which was entered at Daytona, along with the Dick Barbour Racing car. Both were purchased at a modest $230000 each. Charles Mendez and Randolph Townsend had updated their own car to the K3 specs. Peter Gregg would run with his ex-935-78 now owned by Bruce Leven. Charles Mendez had two other cars, one being updated to the K3 specs plus one new car. An old standard car was entered too. Dick Barbour had his K3 and another car, a 79 car for Bob Garretson and Skeeter McKitterick. The Whittington Bros had two cars, a K3 and a standard 935. Ludwig Heimrath had his 78 car as well as John Paul. Joest Racing had a much modified car for Rolf Stommelen, Volkert Merl and Reinhold Joest. Momo Corse entered a 79 car for Gianpiero Moretti. John Paul Jr began his IMSA career with his father at the end of the 1980 season. He proved immediately ultra competitive and almost won from the beginning. He drove a JLP2 prepared car, which was a personal evolution from the standard K3.

In 1980, the K3 cars were widely spread and many cars were to be seen. From complete cars to conversion kits or bodt parts, K3s became the standard. Dick Barbour had purchased three cars, including John Fitzpatrick's one, who clinched the Championship. The 935K3-80 apeared later, with new improvements. The rear suspension pickups were revised. The injection was now from Kugelfisher with a new induction system with larger inlets. Fences had been added to the sides of the engine cover/rear window and this car became one of the most successful in history. Reinhold Joest had built personal versions of the 935. They were called 935Js. These cars featured 935-77 bodywork and a space frame engine compartment similar to the 935 Baby. The air to air intercooler was housed between the engine and bulkhead. The front bodywork was slightly altered. Lower profile fenders would produce a smaller frontal area and small fences on all four fenders and louvres over the front wheels. Such a car won at Daytona with Reinhold Joest, Volkert Merl and Rolf Stommelen driving. They did not win any other race in the year until the Daytona Finale, where Gianpiero Moretti won with Reinhold Joest. The Italian had purchased the car which sported the famous Momo colours. The Bayside Disposal team, owned by Bruce Leven, had purchased the car previously owned by Peter Gregg. They had a very difficult season. The cars, which were updated, were old cars and the season ended with no success and the death of their driver-star Peter Gregg, who had experienced vision troubles and commited suicide.

In 1981, cars would be modified by the Kremer Bros and switched the water to air intercooler to an air to air one. Every car sported this great improvement at the beginning of the 1981 season. Some minor changes were to be seen aesthetically such as a new air intake. John Fitzpatrick had set up his own team, he was assisted by the Kremer Brothers, who had made the trip to the US. The original Porsche 935 parts would be the roof, cowl, door jambs, engine compartment opening, and part of the rear quarter section. Andial had converted a standard twin turbo into a modified version of the K3, which used different aerodynamics and suspension pieces. An air to air intercooled 3,2L twin turbo engine powered the car.This car, driven by Rolf Stommelen and Harald Grohs, had a very successful end of 1981 season. The season would be the first one with a non Porsche victory since the Chevrolet Monza days. Brian Redman dominated the series with his Cooke Woods Racing Lola T600. Gianpiero Moretti would enter a Moby Dick Joest replica during the Riverside event. His former car would be sold to Mauricio de Narvaez.
The following season would see a new life for the now outdated 935s. The IMSA had liberalized the GTX rules in order to give them the power to fight against the GTPs. Full tubeframe chassis were now allowed You could watch cars that were completely and utterly unique. Everyone had his own 935. From the standard K3, the 935/2, Moby Dick replicas, K4, hybrid Lola-Porsche cars, JLP2,3 or 4, or homebuilt 935, you could not find two similar cars. The 1982 saw a big battle between John Paul Jr and the Interscope Lolas, while John Fitzpatrick had some good races with a very impressive Kremer K4. This car had a fully enclosed or covered doors and a raised rear fiberglass roof. The K4 retained the wing fences around the fenders. At the end, John Paul Jr emerged as the IMSA Champion, driving three types or car, from the JLP3 or 4, to a Lola T600. A new star was born.

The JLP3 was built by Chuck Gaa and Dave Klym, and would sweep the 24 Hours of Daytona and the 12 Hours of Sebring in a row. Bob Akin had a hybrid car, that was dubbed the L1. It featured a Lola T600 nose and rear end. While fast, this car handled miserably and Bob Akin hated it. Later, he would commission Chuck Gaa to build a 935-84 car. Andial had a special version of the Moby Dick car built under Glen Blakely's supervision. It was based on the Moby Dick tubeframe design but entirely drafted in the Costa Mesa shop. The car had an excellent debut at Riverside, with Al Holbert and Harald Grohs at the wheel. Later, it was sold to Preston Henn, who later was to bring this car to a great victory at the 24 Hours of Daytona 1983. The Porsche 935 differed not much, in the beginning, from the standard Carrera RSR. A new whale-tail wing, a new four-speed transaxle, the 935 inherited very much of the Porsche Carrera Turbo philosophy. It featured the same coilover suspension, a full cockpit rollcage and a separate X-member stiffing frame that fitted between the inner front bodyshell sheet metal. The two components were made from aluminium alloy. The cars sported too the ventilated, cross-drilled disc brakes from the legendary 917 car. The wheels were 16 inches in diameter with a 12,5 inches width in front and 19 inches in diameter with 15 inches width in the rear. The engine horsepower was supposed to deliver some 650hp which seemed, according to many, under the truth. It was probably much closer to the 750hp. A dual ignition system and its air-to-air intercooler were installed on the car. The 935-77 car roof was flatter than that of the other 911 based cars. Thus it improved the air flow, and the rear wing efficiency. The cars with single turbo dominated the Championship.

In 1981, new cars appeared. The first one was the Andial built car. Run by German expatriates Alwin Springer, Arnold Wagner and Dieter Inzenhofer, the Santa Ana shop had built a special car. It was a 1978 car which had been thoroughly modified. The nose and rear fenders were longer and edged with fences and the rear spoiler incorporated side panels which were very wide. A bigger wing made this car look quite different from the other cars. Powered by a special homebuilt 3,2L, it was extremely fast. While very fast, this car proved much unreliable. Rolf Stommelen and Harald Grohs had a couple of dnfs. Then the car disappeared to be heavily improved. When the car reappeared, it was to produce back to back wins at Mosport and Road America. More radical were the Joest built Moby Dick replicas. Purchased by Gianpiero Moretti and John Fitzpatrick, they would have different fates. While the car proved fast, it would never win in the hands of Gianpiero Moretti , partnered by Jochen Mass, Jim Busby or Bobby Rahal in 1981. It would not be seen in 1982, except in Europe, but was back in 1983, with the Kreepy Krauly support, brought along by talented driver Sarel van der Merwe. The doors were different from the original Works car. JLP Racing had entered their personal idea of the K3, they had modified themselves the car with a Kremer built engine and some parts. Called the JLP2, it still bore a resemblance with the K3, but the cars would then evolve with time. The JLP3 would appear in 1981, which was built by Chuck Gaa in Atlanta. It featured a space frame construction chassis with a high floor sill and the underside area was used as a ground effect wing section. The body shell was still based on K3 parts. A large rear wing was mounted on the back of the standard window/engine cover flanked by two slightly modified rear fenders. The extreme front of the K3 nose was lowered. It would be lowered further later! The doors featured fairings running out of the rear fenders. The Bayside Disposal Racing had their own evolution of the 935 bodywork. It had standard 935-77 type rear engine cover and nose sections. The tail section had been modified and featured distinctive flip out flay sections on top. They won at Sebring with Hurley Haywood and Al Holbert but it was their sole 1981 victory. John Fitzpatrick had set up his own team in 1981, after Dick Barbour's financial setbacks forced him to retire from racing. He had one the latest K3-80, he would have to modify his car, after experiencing efficiency problems. He incorporated small ground effect tunnels behind the rear wheels, which proved efficient as speed was improved. Bob Akin had a standard K3 in 1981, but he entered a more radical car, called the L1, in 1982. It was some kind of hybrid as the chassis was a complete aluminium monocoque with the motor supported on two side braces. The front section of the car was mated to a Lola T600 nose section. The roof line and engine were the only original parts. According to Derek Bell, who drove the car on some occasions, it was the worst car he had ever driven. The car was eventually destroyed at the Daytona Finale, and was never raced again.

John Fitzpatrick had a new K4 in 1982. The car was based on the Moby Dick car, but it featured some differences. The chassis was constructed as a complete aluminium tubing space frame. It used a wider front track, and the under body featured ground effect tunnels. These tunnels were concealed by full body width, upward slanted, slats at the back. The front fenders were even wider and the font spoiler more swept back. Rear fenders were a one piece unit incorporating the rear wing on one central mounting and a secondary rear window. Large section sills joined front fenders to rear and an outlet duct for the front radiator situated on the front lid, and full width doors. Max Crawford re-engineered the Porsche K4 for John Fitzpatrick Racing. The powerplant was a 3,2L twin turbocharged engine with an air to air intercooler. He would eventually win four races with this car. Later in the season, he would race the JR002, which was the second Joest Moby Dick replica. The car would wind up an excellent fourth overall at the Le Mans race, behind the three Works Porsche 956s. JLP Racing entered the JLP4 in 1982, which was more radical. This car was designed by Lee Dykstra and built by Dave Klym. It featured a space frame chassis, but the front suspension was altered to a pure race car type. The springs and shocks were incorporated inboard, which allowed a clean airflow to the full length ground effect Venturis beneath the car. The car was now a right hand drive. The bodywork was completely reshaped, with slab sides and a low nose with no front bib spoiler. This car was mainly aimed at the shorter event races, while the JLP3 was used for the endurance races. John Paul Jr won at Brainerd and Portland with JLP4. However, the car was finally destroyed in a test driving session at Road Atlanta, when the rear wing took off. The Pauls father and son finished the season with JLP3, and Jr easily won the 1982 crown. Interscope Racing had a pair of K3s and two K4s, but these ones were never actually used by the team. They concentrated on their newly acquired Lola T600s. The old JLP2 was run by Mark Speer and Terry Wolters, with little success though. The Bayside Disposal Racing entered some selected events with a slightly evolving car. Charles Ivey Racing entered some races with a standard K3 car. Preston Henn supported several cars during the season, but the most impressive one was undoubtedly the Andial built car. This was some kind of Moby Dick replica but had a lowered space frame chassis, wider front track and a long tail body with full width door panels. The tail section was a single moulding aft of the rear wheel arches incorporating the rear window. This section was hinged at the top of the window to tilt up for maintenance. The rear end was completely open. Al Holbert and Harald Grohs powered this car to an impressive second overall at Riverside. Later it would reappear at the end of the season in the hands of different drivers, but its greatest achievement would take place the following year when winning the 24 Hours of Daytona with Bob Wollek, Claude Ballot Léna, AJ Foyt and Preston Henn driving.

In 1983, the IMSA series was the only Championship where you could find 935s running, and still running strong! Bob Akin had switched back to his old faithful K3 for most of the season, but at the Daytona Finale, he had a new car, the 935-84. This car had a wider front track, a Kremer K4 front end, wide doors and a special tail which was something between the K3 and the K4. The rear window/engine cover piece had a reduced height and an open tail end fitted with full width upward swept slats. The John Fitpatrick K4 won at Riverside but this event was marred by Rolf Stommelen's death. He was driving the JR002 car which was written off in the process. The Bayside Disposal team entered a car that displayed a lowered tube frame chassis, wide front track and fenders and most of all, a distinctive tail section. Gianpiero Moretti entered JR001 alternatively with the March 83G Porsche, with some consistent results, but no win.
In 1984, some of the 935s were still running, but it would be difficult for these cars to be as efficient as they were, because of the now widely spread GTPs. The 962 was now available to the top teams and the 935s would be sold to less efficient ones. However, the beginning of the season brought its share of good surprises when Preston Henn's faithful Andial built 935L nearly won the 24 Hours of Daytona. AJ Foyt, Bob Wollek and Derek Bell took a strong second behind the winning March Porsche.

Sebring was still more upsetting with the overall win for a Joest built 935J. Stefan Johansson, Hans Heyer and Mauricio de Narvaez drove an outdated car to victory, just in front of Bob Akin 935-84. The remainder of the season was to be a big fight between the Holbert Racing Porsche 962 and the Blue Thunder Racing March 84G Chevrolet, which eventually won. The 935s were no longer developed, and were to be seen in new liveries, according to their new owners sponsors. The same could be said about the 1985 and 1986 seasons. Preston Henn still entered his old Porsche 935L, which would be driven by Bob Wollek, Don Whittington and Preston Henn, along with the new Porsche 962. Starting fourteenth, it was still able to run fast, but it was obviously the end of a glorious career. The car would no longer be entered in the season. Marty Hinze had acquired the JLP2 running under his yellow colors, and it started seventeenth. The Toyota Village car, with a special design, started twentieth and would not finish. It was probably the latest modified 935, with a special front end and a very high wing. The Paul Goral entered car would simply run with the best GTU cars! The days of the 935 were gone!
This fantastic machine would be seen for two last appearances in 1986, with some very anonymous results. Then, no car would be entered in the IMSA Championship. But they would simply be never forgotten, and they remain very popular today with a lot of fans and collectors still running them in Vintage races.

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