Class Warfare - 1993 Opel Calibra V6 4x4 DTM
Taking things to the next level
In 1982, the world of motorsport was faced with an industry-wide reorganization instigated by the Federation Internationale de l’Automobile. As part of the changes, touring car racing was extensively restructured, replacing the lightly modifiable Group 2 and the extremely savage Group 5 machines with a far more conservative formula.
This new category, Group A, featured very stringent homologation requirements. In order to qualify for competition, the competing model needed to be produced at least 25,000 times. Furthermore, the FIA required ten percent of these cars to be a specialty model, with another 500 allowed as “Evolution” models. If the 25,000 car limit had not yet been met, the new model had to attain a production number of at least 5000 units a year.
DTM eagerly embraced the highly competitive Group A formula.
For the bustling West-German racing scene, this meant the formerly popular Group 5-based Deutsche Rennsport Meisterchaft (German Racing Championship) had become redundant. However, it would take until 1984 before an alternative would arrive.
This Deutsche Produktionswagen Meisterschaft, (German Production car Championship) adopted Group A two years after its introduction, which meant there were already plenty of developed cars to fill the grid. The series quickly rose in popularity, and was finally renamed Deutsche Tourenwagen Meisterschaft in 1986.
The tyrannical four-wheel drive Audi V8 ended Group A in Germany.
Factory involvement from BMW, Mercedes-Benz, Rover, Ford, Opel and finally Audi propelled the DTM into the public eye. With cars strongly resembling the ones parked down virtually every street, the series managed to gain traction among the average car buyer. Nowhere else could you see your uncle’s boring Rover take on your dad’s humble Ford in a ferocious battle to the finish line. With contact a frequent occurrence, the spectacle was complete.
Unfortunately, Audi took things a step too far in 1990, when it unleashed an unlikely super weapon. A massive 4.8 meter limousine powered by a V8 created from two Golf GTi 16V engines: the V8 quattro DTM. Helped by 450-500 horsepower and quattro four wheel drive traction, the huge brute took the 1990 and 1991 championships by storm, embarrassing BMW and Mercedes-Benz in the process. When the company took the liberty of fitting a modified flatplane crankshaft in 1992, the jig was up.
Opel struggled to get to grips with the Group A era.
In response to Audi’s unfair advantages and the cheating scandal, DTM’s governing body Oberste Nationale Sportkommission für den Automobilsport axed Group A for the 1993 season. Instead, the ONS moved to form a brand new top category of touring car racing in conjunction with the FIA.
This formula became known as FIA Class 1 Touring Cars, and set up an unusually liberal set of regulations. In essence, any car competing could have a maximum engine displacement of 2.5L divided over a maximum of 6 cylinders which were allowed four valves each. \
In addition, the engine used had to be at least loosely based on a production block. Other than this, all bets were off. Sequential shift gearboxes, four wheel drive, traction control, electronic differentials and anti-lock brakes were all allowed. The aerodynamics package was free as well, as long as they were kept below the centerline of the wheels.
Opel picked the sporty Calibra as its new DTM hero
For German manufacturer Opel, the regulation change came as a godsend. The company had been struggling to keep up with the front runners since they’d joined the top displacement class in 1988. Their Omega 3000 24V proved hopelessly unreliable, and the Evo 500 evolution-spec suffered from its excessive size.
The car was roughly the same size as the dreaded Audi V8, but lacked the power and four wheel drive traction to keep up. Owing to Group A’s strict homologation rules, Opel had no way of bringing the car up to speed without building a dramatically expensive road car as well. In the much looser environment offered by FIA Class 1 however, this was no longer an issue.
The screaming V6 was developed with assistance from Cosworth.
Taking advantage of their newfound liberty, Opel’s engineers took the steel bodyshell from the brand’s sporty coupe, the Vectra-based Calibra as a starting point. Normally this car sported a transverse engine, front wheel drive layout, but this setup was of course not even close to what Opel had in mind.
As such, the car’s 2.5L C25XE V6 was turned around 90 degrees to assume a longitudinal position. Keeping only the most essential bits, British engineering firm Cosworth turned the 170 horsepower engine into a large bore, short stroke masterpiece. Using design principles akin to those used in Formula One, the unit belted out 420 horsepower at 11,650 rpm.
Opel's impressively compact drivetrain package.
Influenced by the success of the Audi V8 quattro and the new Class 1 Alfa Romeo 155 V6 TI, the decision was made to integrate an advanced four wheel drive system. Crucially though, Opel worked hard to avoid the balance issues seen with those cars.
Thanks to some mechanical trickery, the engine was placed far back in the chassis.
Thanks to the intricate four wheel drive systems, their engines had been placed far in front of the front axle line. As a result they had the tendency to understeer quite badly. In a bid to solve this issue, the engineers placed the engine inside the front axle.
Using a gear-driven system, power was taken from the 6-speed sequential gearbox forward to the half-shafts, which appeared to embrace the raucous 54 degree V6. By doing this Opel had cleverly avoided a nose-heavy car, giving them a significant handling advantage. Weighing in at 1040 kg (2292 lbs)m the car looked like a serious challenger for Alfa Romeo.
The Calibra's inital bodystyle was fairly conservative.
In the chaos following the switch to Class 1, Alfa Romeo had been the only competitor to properly develop a car. With Audi and BMW dropping out, Mercedes-Benz had been unsure about continuing its commitment to DTM.
At the last second the Germans decided to stay, which left them with no other option than to hastily update the four-cylinder 190E 2.5-16 Evo 2 to Class 1-specs. Left without any meaningful competition, Alfa Romeo quickly wrapped up the teams and driver’s championships, with Formula 1 driver Nicola Larini (ITA) taking top honors.
Keke Rosberg testing the Calibra, Hockenheim 1993.
Hoping to steal the Italian’s thunder, Opel employed the services of multiple Le Mans winning team Joest Racing. Joest was tasked with the development and running of the ambitious project, ensuring a professional and methodical approach to Opel’s biggest racing effort yet.
With a world-class team came world-class driving talent. Two cars were entered into the last round of the 1993 season, staffed by DTM-veteran and 1989 Le Mans winner Manuel Reuter (GER) and 1982 Formula One World Champion Keke Rosberg (FIN).
Keke Rosberg lining up on the grid, Hockenheim 1993.
The last round of the 1993 season took place at the extremely fast 6.8 kilometer Hockenheimring, which included long straights through a dense forest. Broken only by a few chicanes, this section marked the track as the ultimate test of horsepower.
As it turned out, the Opels were still lacking in this department. Manuel Reuter was fastest of the two with 5th on the grid, while Keke Rosberg clocked a disappointing 9th time. Both managed to be slower than several of the lesser Mercedes. Both races left much to be desired as well, with Rosberg finishing 7th in Race 1. Reuter retired with electronic gremlins after just 6 laps, and was forced to miss Race 2. Rosberg was felled by similar issues in Race 2, and slowed after 10 laps.
The car failed to make an impression on its debut.
After a less than encouraging opening weekend, Joest Racing, Cosworth and Opel regrouped to take on their first full season together in 1994. Sparing no expense, the cars were completely overhauled. A bespoke suspension setup replaced the production-derived arrangement from the 1993-cars, offering a far wider range of adjustability.
Furthermore, the front end was completely stripped of any superfluous sheet metal, and was clad in a composite one-piece clamshell to reduce weight and increase rigidity. The changes were complemented by lighter multi-spoke BBS wheels, and an evolved aerodynamics package, which further distanced the car from the production model. Meanwhile, Cosworth managed to extract some more revs (up to 12,800) to fire 457 horsepower at all four wheels.
Confident in the heavily reworked Calibra’s potential, Opel Team Joest expanded to a three car team. The third car was taken by John Winter, a successful businessman and sportscar racer for Joest. Winter took the top step of the podium at the 1985 24 Hours of Le Mans and the 1991 24 Hours of Daytona, as well as becoming German Interserie Champion in 1986.
Keke Rosberg (left) and Manuel Reuter (middle) were joined by John Winter (right) for 1994.
However, Opel Team Joest was in for a tough fight. Not only had Alfa Romeo not been sitting on their hands, Mercedes-Benz had finally found the time to build a proper Class 1 car. Although the C180 V6 DTM lacked four wheel drive and only produced 400 horsepower, it featured a 6-speed sequential transmission, F1-derived active suspension, an innovative active ballast system which counteracted the pitching and diving of the nose under acceleration and braking and an all-carbon bodyshell bringing weight down to 980 kg (2161 lbs).
Keke Rosberg, Zolder 1994.
At the first round of the season held at the former Grand Prix track of Zolder in Belgium, Opel Team Joest’s misfortunes continued. Manuel Reuter retired in the early stages, with both John Winter (16th) and Keke Rosberg finishing a lap down on winner Alessandro Nannini (ITA) in the Alfa. Race 2 was more positive however, with only John Winter dropping early on. Reuter lead the Opel charge in 7th, with Rosberg in 10th.
The second round took Opel back to the Hockenheimring. Race 1 was again a disappointing affair, as both Rosberg and Winter failed to finish. Manuel Reuter kept his chin up with 8th, but the Calibra still wasn’t performing as the team had hoped.
John Winter was sidelined for Race 2, but his teammates more than made up for his absence. Keke Rosberg scored Opel’s first podium in the series with third, followed closely by Manuel Reuter. Finally the hard work seemed to start paying off for Opel Team Joest.
The Calibra was still struggling to keep up with its competitors.
After the uplifting podium at the Hockenheimring, Opel fell right back into the deep hole they were working so hard to crawl out of. For the next four rounds and eight races, the team couldn’t reach further than 5th place, and experienced numerous mechanical failures. The trips to the Nurburgring, Mugello, back to the Nurburgring and the Norisring all proved fruitless for the outfit.
The team finally got their sweet release at the series second international round. Round 7 of the championship was held at beautiful swooping track of Donington Park, and looked to be dominated by the respective armada’s of Mercedes-Benz and Alfa Romeo once again.
For Race 1 this was indeed the case, but the tables were turned soon after. Manuel Reuter was declared the surprise winner after Alessandro Nannini was disqualified for using too much fuel. Sadly the win did not count for the championship, but Opel had made its mark regardless.
Manuel Reuter in his office.
Unfortunately, Opel’s first victory in the DTM turned out to be as much of a fluke as the podium at Hockenheim. The Calibra’s fell behind once more, and resorted to occupying the lower end of the top 10. The airfield circuit at Diepholz, a third visit to the Nurburgring and the high-speed section of autobahn known as the AVUS-ring were all without meaningful results.
While at the AVUS-ring, John Winter suffered a horrendous accident after being nudged by one of the Mercedes on the opening lap. He was pitched into a high-speed half-spin to the right, and hit the barriers with enough force to rupture the fuel tank. A gigantic fireball erupted from the destroyed car, but Winter was able to crawl out relatively unscathed. With only minor burns to his face, he was lucky to be alive.
However, the spectacular nature of the accident lead to him being interviewed on live TV. For an ordinary driver this would have been a formality, but John Winter was a special case. In fact, his name wasn’t “John Winter” at all. “Winter” was actually Louis Krages, a wealthy businessman who saw racing more as a hobby.
He had hidden his identity under a pseudonym to avoid concerning his family with his dangerous activities. Krages had confessed to racing after the publicity of his Le Mans win in 1985, but the high-profile accident at AVUS moved him to abandon his alter ego altogether for 1995.
The penultimate round of the season yielded another rare high point for Opel, as Manuel Reuter managed to drag in another podium. The venue was an industrial estate near the city of Singen, with short straights and 90 degree corners. Reuter finished third behind the two Alfa’s of Nicola Larini and former F1-driver Stefano Modena.
Manuel Reuter and Keke Rosberg tripping over each other, Singen 1994.
The final round of the 1994 season was contested at the Hockenheimring, but again the Opel contingent did its laps in relatively colorless fashion. A strong fourth place from Manuel Reuter in Race 2 ended the Calibra V6 4x4’s first full season. For 1995, the car would again be almost completely reshaped into a more effective weapon to take out the big boys in the newly renamed International Touringcar Challenge.
The Opel Calibra V6 4x4 DTM was an ambitious attempt by a cornered manufacturer. Stuck in the middle with their largely useless Omega, Opel rejoiced at the opportunity to start with a clean slate as FIA Class 1 blasted onto the scene in 1993.
Taking a good long year to plan their assault on Alfa Romeo, the company enlisted the best names in the business in the hope of quickly conquering what was steadily becoming the world’s most prestigious touring car series. Unfortunately Joest Racing and Cosworth could only do so much. Even with the immense talent of three very determined drivers, the first iterations of the Calibra just didn’t cut it. A lucky win and two random podiums was all it could muster.
The Calibra would be back for more.
Faced with an ever-evolving Alfa Romeo and a regrouped Mercedes-Benz, the company was simply lagging behind for the second time during their short DTM career. It was clear something drastic had to happen to bring the car up to speed. With Joest and Cosworth sharpening their swords for a definitive strike, 1995 would have to be Opel’s breakthrough once and for all.