Mazda RX-792P
The Mazda RX-792P was a racing car built by Mazda for the IMSA GTP championship. His career was very short lived; only two cars were reported in the 1992 season before the project was discontinued. The name of the car is a combination of the contemporary sports car model RX-7 , the 1992 racing season and the letter P for prototype.
development
After many years of successful use of the RX-7 in the IMSA GTO class and the MX-6 in the IMSA GTU class, Mazda decided to take on a new challenge. Although Mazda had supported the use of its Wankel engines in the IMSA GTP class in the past , they wanted to compete on equal terms with the works teams from Porsche , Nissan , Jaguar and Toyota . This coincided with Mazda's involvement in the World Sports Car Championship in Europe and in the All Japan Sports Prototype Championship (JSPC) at home.
After Mazda's victory in the Le Mans 24-hour race in 1991, a rule change by the FIA forced the company to abandon its 4-disc rotary engine in the World Sports Car Championship. However, the IMSA rules still allowed the use of rotary engines, which prompted Mazda to bring the R26B engine to the USA and adapt it to the shorter racing times and racetracks.
For the chassis, Mazda used the experience of Crawford Composites , with Fabcar assisting with the project. Because of the different racing styles, the new car looked little like the old 787B and its predecessors. The monocoque was built from CFRP and the body, which was designed by Lee Dykstra , showed new, flowing lines and a large ventilation opening behind the front wheel arches.
A total of three Crawford RX-792Ps were built for Mazda before the project was canceled.
Racing history
Mazda Motorsports ensured that the first RX-792P was ready just before the start of the 1992 racing season. The team consisted of the drivers Price Cobb and Pete Halsmer . The decision was made to skip the Daytona 24-hour race , and so the car first appeared at the Miami Grand Prix . A fire caused by the hot exhaust hitting body panels caused the car to be withdrawn from the race before it even started. This problem continued at the Sebring 12 Hours , where the car caught fire again shortly before the race.
The second RX-792P chassis was ready for the next round in Road Atlanta . Both cars were reported, but an accident prevented the second car from starting. The only remaining RX-792P was able to start but finished the race in 25th place, 20 laps behind the winner. When the second car was repaired, both cars were able to start in Lime Rock Park , where they could finally show their potential. In qualifying they were still in the middle of the field, but finished the race in 3rd and 4th place, only three laps behind the leading Toyota . The cars finished 6th and 9th on the Mid Ohio Sports Car Course .
There were problems again in New Orleans , where only one car could place in sixteenth. Nevertheless, the team recovered quickly and achieved the best result of the season with 2nd place at Watkins Glen International , even though the car was five laps behind the winner. A 7th place in Laguna Seca was unfortunately followed by a failure of both cars in Portland .
A 4th and a 5th place were achieved at Road America , but then both cars retired at Phoenix International Raceway . This trend continued in the last race of the season, when neither car saw the black and white flag. This string of poor results earned Mazda only sixth place in the constructors 'championship, despite Price Cobb finishing eighth in the drivers' championship.
Suspension of the project
After the 1992 season, racing in the world underwent major changes. Both the sports car world championship and the JSPC were canceled, so that the more expensive MXR-01 could no longer be used. At the same time, IMSA announced plans to abolish the GTP class in late 1993 and instead turn to a new category of open-cockpit prototypes. This meant Mazda only had one more season to run the RX-792P in the US before they had to design a completely new race car.
But efforts on the RX-792P were in full swing and the group was busy making improvements to the chassis. On the sliding weight / displacement scale of the IMSA, Mazda's 4-disc rotary engine was 793 kg and many teams were bothered by this, thinking the Mazda engine had undue advantages in terms of power-to-weight ratio . The RX-792P occasionally drove fast enough, in fact the machine gave way too much power compared to its competitors and thus stamped the perceived power-to-weight ratio to a perception that had nothing to do with reality. And any advantage that might result from this was nullified by the need to cool the car and the corresponding grip-performance ratio.
With that in mind, Mazda thought about what could be done to fill the performance gap. Mazdaspeed supplied the 4-disc rotary engine of the program and had further developed versions in the test that developed over 700 bhp (515 kW). “Needless to say, we're excited and looking forward to the 1993 season,” said Dick St. Yves , Mazda Motorsport Director 1988-1993. As a result, the design was improved so that the oil cooler moved to the sides of the vehicle and the front-mounted engine cooler was enlarged. A weight reduction program was also considered as the cart never exactly reached its minimum weight of 793 kg; usually he was about 34 kg higher.
The RX-792P program was managed on an astonishingly low budget, according to Dick St. Yves: “I was told that Toyota's budget was $ 20 million and Nissan's budget was around $ 25 million ; our budget was US $ 5 million. ”The program started in May 1991 in an empty warehouse in Charlotte, North Carolina and by February 1992 the first car was bolted together in these adverse conditions. The 4-disc rotary engine delivered incredible power, about 200 bhp (147 kW) more than its competitors. And although the regulations seemed to give Mazda a weight advantage, he never did. If the first year were viewed as a development year, as happens with all one-year miracles, the second year would have had much to offer. St. Yves emphasized that the 1993 budget was approved by Mazda USA in October 1992, but Mazda Corporation announced a month later that it wanted to withdraw from racing: “The four-disc rotary engine was the only component of the Car that actually came from Japan. We were informed a few days later that they were going to end the experimental engine program - as far as the four-disc rotary engine was concerned - and that was the end of the RX-792P program. ”So the story ended on a budget but without an engine. In December 1992 the gates closed for good.
Web links
literature
- Fuller, Michael J. and Martin, JA: Inside IMSA's Legendary GTP Cars: The Prototype Experience , Motor Books International, Minneapolis (2008), pp. 232–245.