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The XJR-5 was a prototype racecar made by Jaguar for competition in the 1983 series.

The XJR-5 is powered by a 60-degree normal V12 engine that has a displacement of 6000cc. It produces 650bhp at 7500rpm and 479.25 Fft-lbs of torque at 6000rpm. The XJR-5 was fitted with a manual transmission. The Jaguar XJR-5 designed especially for competition in the IMSA GTP class.

Tullius was able to persuade Mike Dale Jaguar Cars Inc. in New Jersey to fund this project. Designer Lee Dykstra was tasked with creating a car that can receive the engine Jaguar V12 racing. Group 44 ‘s previous four XJR cars 1 to 4.

The hired designer was Lee Dykstra, whose Special Chassis Inc. had designed a successful ground effects racer in 1980. Dykstra decided to use the long and relatively heavy V12 engine as stressed chassis member. The engine was bolted directly on the aluminium monocoque, supported by four stiffening struts bolted on the firewall. The slim design was completed by attaching the rear suspension on the transaxle, leaving plenty of space for underbody aerodynamics.

Pioneered by Lotus in the late 1970s, ground effects aimed at reducing the air pressure under the car. Grip was created by the low air-pressure 'sucking' the car to the ground. To create ground effects, the underbody of the car was shaped like the top half of an airplane wing. The XJR-5's slim monocoque chassis allowed for large, clean 'wing' surfaces on each side of the engine. After many wind-tunnel tests of quarter scale models in the Williams rolling road wind-tunnel, two underbodies were constructed. A low drag, low downforce version for high speed tracks like Le Mans and Daytona and a high downforce one for slower tracks.

In TransAm spec, the V12 engine was fed by six Weber Carburettors, this setup was carried through on the GTP car. In the first full season of racing the Webers were still used, but as a Le Mans entry came closer work was started on a computer controlled Fuel Injection system. Fuel efficiency was vital at Le Mans, where the quantity of fuel available was restricted. First tested in December 1983, the Lucas Micos system provided both a better throttle response and a higher mileage.

Teaming up with co-driver Bill Adam, Tullius debuted the XJR-5 in the 1982 Road America round of the GTP championship. The result was better than anyone could have hoped for, with a third place overall and a win in the GTP class. Small problems in the next few races prevented the XJR-5s to copy the Road America performance. Jaguar scored the first victory in the 1983 Road Atlanta 500km race, with Tullius and Adam at the wheel. In the next couple of seasons, more victories were scored, but the team was never a contender for the championship against the much more powerful Turbo-charged Porsches, Nissans and Toyotas.

Impressed by Group 44's performance in 1983, Jaguar was growing more comfortable in supporting a Le Mans return, especially now that the V12s were equipped with the Micos system. After a series of successful long distance tests in the first months of 1984, Jaguar was convinced and agreed to back Group 44's Le Mans entry. The XJR-5 was the first Jaguar to compete at Le Mans in 22 years and the first factory backed Jaguar to enter since the glory days of the 1950s. Although no match on speed for the Turbocharged Lancias and Porsches, the two entered XJR-5s were running in sixth and seventh when they retired around the 14th hour of the race. The XJR-5 returned to Le Mans once more and claimed 13th overall and a win in the GTP class.

Although successful, Group 44 lost their factory backing to Tom Walkinshaw's TWR. Late in 1985, Tullius nevertheless launched the XJR-7. This featured a Kevlar reinforced chassis and more refined aerodynamics. It debuted at the Daytona 3 Hours late in 1985 but the XJR-7 did not win until the same race a year later. In 1987 two more victories were scored at Riverside and Palm Beach. The Group 44 Jaguar was last raced in the 1988 Daytona 24 Hours. The American team did not return to Le Mans after 1985 where Jaguar was now represented by TWR with outright victories in 1988 and 1990 as a result. It should however never be forgotten that it was Bob Tullius and his Group 44 team that brought Jaguar back to the legendary endurance race.

The Cars

Chassis XJR-5/001

This is the very first XJR-5, which was designed and developed in the first half of 1982. In August that year, it was successfully debuted by Bob Tullius and Bill Adam in the Pabst 500 at Road America with a third overall and a first in the GTP class. Tullius drove the car for two more races that year, scoring a second as best result. It served as a spare chassis for the 1983 season and was later also used for suspension development. Currently fitted with a Weber equipped V12 engine, it is still owned by Bob Tullius.

Chassis XJR-5/004

Chassis 004 was one of the most successful of all XJR-5s. It was raced extensively by Group 44. Upon its retirement, it was sold to Peter Kaus, who displayed it in his Rosso Bianco Museum. Before the car was shipped to Germany, it only received a cosmetical restoration and a tag was applied to the chassis that the car should be used for display purposes only. Kaus sold his entire collection, including the XJR-5, in 2005. The new owner offered chassis 004 at Bonhams' Quail auction where it sold for $238,000.

Chassis XJR-5/006

Chassis 006 was used extensively by Brian Redman in the 1984 and 1985 seasons. Partnered by Doc Bundy he famously won the Miami Grand Prix early in 1984. Redman also raced the car at Le Mans. In 1984 he was joined by Claude Ballot-Lena and John Watson and in 1985 by Hurley Haywood and Jim Adams. An accident and a CV-joint failure respectively ended chassis 006's early at both occasions. At the end of the year, chassis 006 was sold to TWR and used for testing in preparation for their Le Mans program. In 2000 it returned to the market and today it is owned by an enthusiastic racer.

Chassis XJR-5/007

Built in 1984, chassis 007 was raced for the best part of two seasons. It was used extensively by Bob Tullius and Chip Robinson. The two American racers scored various 2nd and 3rd place finishes but missed out on a well deserved victory. After its contemporary racing career chassis 007 was sold by Bob Tullius. In recent years, it was restored to full running order. The work took nearly five years but the result was well worth it.

Chassis XJR-5/010

Although two high numbered XJR-5s exist, chassis 010 was the final car built and raced in period. Although most likely first constructed in 1984, it was not raced until the 1985 season. It is believed that it appeared only once, at the Daytona 24 Hours race. Piloted by Chip Robinson and Claude Ballot-Lena, it completed 212 laps before an oil-pressure problem caused an early retirement. Today it is still owned by Bob Tullius.

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