Turbocharging for (nearly) all
Ranging over Germany and Belgium, the deutsche Rennsport Meisterschaft is an 11-round series that caters for some superbly engineered cars of extraordinary value. Basically the cars conform to Group 5 of the FIA International regulations, popularly known as the Silhouette formula. There are exceptions here and there, but largely this has been interpreted as the right to build a Porsche 935 (the turbocharged racing 911) with a fascinating profusion of bodywork styles for the over-2,000-c.c. class. Under 2,000 c.c., a bitter fight between those perpetual rivals at Ford and BMW is now overshadowed by the intervention of a works 1.4-litre Porsche 935, driven by Martini Porsche Group 5 World Championship regular Ickx.
The type of the racing could be seen within a supporting race preceding the German GP at Hockenheim. The drivers comprise some familiar names from international racing, mainly with a touring car bias, with a sprinkling of local heroes thrown in. Hockenheim comprised the sixth round of the Championship, the 2-litre division of which has inspired the FIA to make the same provision in next year’s Silhouette series, which could attract more attention than the fleet of Porsches sweeping up the events from the front. It is perfectly possible that Porsche themselves may continue to relentlessly hunt down the opposition and appear in the little class, possibly leaving the overall victories for the fleet of turbo Porsches now in private hands, despite the things the factory say at present.
Hockenheim emphasised the Porsche monopoly over 2-litres, by turning up a new car in the division to relieve the monotony. This was a toy for Harald Ertl, the bearded engineer-cum-journalist who had then just lost his rented drive in the Hesketh Formula One team. Constructed by the Schnitzer brothers in Freilassing, Austria, the car was a radical, mis-shapen, Toyota Celica. The coupé was financed by the Belgium-based Toyota team, managed by expatriate Swedish rallyist Ove Anderson.
With that international flavour behind it the Toyota was quite straightforward within. At the front stood the 2-litre, 16-valve motor normally used for rallying. Prepared by Schnitzer this should normally produce 230 b.h.p.: however the addition of a turbocharger was said to have boosted peak power to 560 b.h.p. at 8,800 r.p.m. As with the 630 b.h.p. (minimum: the drivers can, and do, alter boost) Porsches the turbocharger unit was provided by KKK. That 560 horsepower was quoted at 1.4 atmospheres of boost: this is very close to the figures used on the 2.8-litre flat-six Porsche motors, though both leading contestants are said to have run up to 1.7 atmospheres in the effort to win, risking the engines. The fact that a turbo Porsche engine represents nearly £18,000 of these £38,000-plus machines, does not seem to deter property magnate Georg Loos form telling his lead driver Rolf Stommelen to “turn up the wick”.
The Toyota was not to be a relevant force over the weekend. It had barely been finished, but Ertl said, “if we can get maybe five straight days of testing with this car, then I believe it will run with the Porches at the front.” One factor that helps that optimism is that the 2,090-c.c. Toyota weighs but 1,892 lb., while the Porsches are quoted by the factory at 2,134 lb.
The Porsche front runners at Hockenheim were Manfred Schurti, the sometime factory driver, in a Jaegermeister-sponsored 935 from Max Moritz. Then there was the neatly divided war between two Erwin Kremer cars for Bob Wollek and John Fitzpatrick, confronted by Stommelen and Tim Schenken. Slightly ironic this, for the two British-based drivers are more usually associated as team-mates in one of the troubled Leyland Broadspeed Jaguars.
Those names really finished the competitive front runners. Just half a minute behind them would set out the numerically far larger 2-litre runners. This meant we had over 40 cars on the track at once. Quite how they did not get involved in each other’s accidents, including a first corner starting collision amongst the big cars, is a mystery to this writer, then concentrating on the start of the smaller division! The lower capacity cars divided into two camps: Martini-Porsche and The Rest. It was only the second appearance of the 1,425-c.c.-engined 935/2.0. The first outing, at Diepholz airfield circuit had been a poor debut by Porsche standards, the cars being withdrawn from a lowly class placing with reported overheating of the driver! Considering Mr. Ickx’s record this seemed unlikely in a sprint event, wherever Porsche had mounted the hot mechanical components.
Be that as it may, the car we saw at Hockenheim was more than a match for The Rest. In fact is was nearly three seconds faster than the opposition in practice. With a wettish track to race on, it seemed very unlikely that anyone would catch Ickx.
While the conventional 935/77 measures 2,857 c.c. from a 92 mm. bore and 70.4 mm. stroke, the smaller engine dimensions some from a 71 mm. bore and a 60 mm. stroke. Both units share a nominal 6.5 to 1 c.r. without boost; Bosch Kraftsoffereinspritzung (often known as fuel injection) and KKK turbocharging.
Maximum power and speed for the small-engined car are quoted as 370 b.h.p. at 8,000 r.p.m. and 168.2 m.p.h. The 2.8-litre offers 630 horsepower at the same r.p.m. and a factory quoted 211.8 m.p.h. the 935/2.0 also differs from other 935s in the use of 13½ in. rear rim widths; a five-speed gearbox in place of a four-speed and the amazing differences in racing weight. The 935/2.0 is said to be 484 lb lighter. How did they manage that? The answer is, we do not know as yet. Doubtless preparing a car for 20 laps at Hockenheim as opposed to six hours at Nurburgring allows a great deal of leeway in weight saving, thought he quoted saving of a mere 20 litres in fuel tank capacity and the general external appearance of the car make it hard to see how Porsche have made their dieting so effective.
Naturally the car has aroused a great deal of interest, carrying an engine that would be the right size for F1 and going a lot faster than 370 horsepower would suggest. We were unable to gain a proper look around the car to verify one experienced competitors’ comment that the engine layout has been tidied up (particularly the cooling of the air for the turbocharger) so that a formula car installation would be much easier than before. We hope to look more closely at the car soon.
Meanwhile Porsche’s Manfred Jantke said enigmatically, “we have done a great deal of development in the three weeks between Diepholz and Hockenheim. I think the car is good for interest in the German Championship, but I don’t think manufacturers like us should be in the little class of a World Championship . . . and no, we don’t have any plans for F1!”
The rest were led by Schnitzer’s other turbocharged devices, 1.4-litre BMW 320is. These carry the factory developed plastic bodywork, but the four-cylinder, 16-valve engines are tubocharged, using the expertise of Josef Schnitzer. The latter has recently returned to the family business after a spell with the Munich competition department developing the turbo straight-six that is said to make 900 horsepower available to BMW when they finally to appear with their mid-engined competition car for 1979. Best Schnitzer BMW driver was Peter Hennige, but after him the conventional 2-litre warriors appeared in their best warpaint. The trio of BMW Junior Team 320i cars (approximately 300 horsepower from their Formula Two engines) was led by Marc Surer, who was about to lose his racing licence for some of the earlier stock car racing rounds in which he had been such a prominent aggressor. He had recorded the same time as Formula Two American Eddie Cheever, both 0.4 sec. faster than the best Zakspeed Escort, that of Hans Heyer, could manage. The Escorts have really gone to the limits of their 2-litre Cosworth-Ford four-cylinder ancestry, developed to the maximum side-radiator form with blanked-off front grilles. Weighing 22 lb. less than the Porsche, the Zaksped cars represent an ultimate in conventional development, but the Ford people were sure they needed to have turbocharging to get any real forward progress.
The works 320i are just as well developed as the Escorts of course, but they look and weigh-in on a rather more bulky scale. The chassis is so well developed that honorary “Senior Team” members Hans Stuck and Ronnie Peterson find it very hard to go any faster than the juniors. Even amongst the Juniors Eddy Cheever has a far more proven and successful record than Surer and Manfred Winklehock, yet he too finds himself attacked constantly by his team-mates: the cars are so well matched, and so comparatively easy to drive that the three team drivers from backgrounds as diverse as saloon car racing, Super-Vee and International Formula Two find themselves bouncing off one another at frequent intervals.
Further back we found the Grab Weisberg-sponsored Escorts. These have normal 2-litre racing engines of Cosworth-ford ancestry, but the bodywork is in exotic carbon fibres to try to gain a weight advantage.
The race itself was somewhat muddled by the change in weather from humid rain to heavily overcast with a rapidly drying track. The Porsches swooshed up to the first corner and sharply disposed of their pole position man (Schurti) into the grass outfield, Sommelen, Schenken and Wolleck taking up the running ahead of Fitzpatrick.
Meanwhile the tiddlers were away as well. Competition was far more fiercely fought throughout the field and was especially notable for the amount of aggressive barging that went on. In fact Henninge’s BMW suffered a damaged rear oil radiator at this point, and fell back to leave Ickx to bring the Porsche back into the Stadium first. Surprisingly close was Heyer’s Escort’ Cheever’s BMW was third, a fitting variety for a national series.
In the big car race the battles were soon over. Stommelen led until half the 20 laps had been completed, then Wollek took him, having spent the opening half a dozen tours behind Schenken, disputing second overall. Wollek did find Stommelen getting close to him in the later stages of the race-“the traffic was so bad I nearly had to stop,” the Frenchman said later, but the drove the immaculate sea green Porsche in a clean style that exactly matched the car’s artistic presentation, to win comfortably. Stommelen took second for the Georg Loos team, his colleague for the day, Tim Schenken, being third ahead of John Fitzpatrick. An interesting aside here was that Fitzpatrick’s white 935/77-Kremer was announced as the fastest car through the radar trap in this event, recorded at 186 m.p.h. This, despite the fact that John apparently has to preserve his car for the remainder of the German Championship on the existing engine, rather than run maximum boost in the hope of winning an individual round.
The small cars provided the highlight of the race. While Ickx took the slightly shriller-sounding Porsche to a bigger and bigger lead, Heyer’s Escort blew up (at half distance). The Hezemans Escort suffered low fuel pressure, and the other opposition (including Armin Hahne’s Zakspeed Escort, which had no clutch) dropped away, leaving a traumatic fight between the BMW Junior Team for second place.
The winged white BMWs flew into the Stadium area for lap after lap in a different order, once Cheever had been unseated from his initially strong position. They would clamber all over the kerbs, six beady eyes scanning furiously for a sign of weakness as they all resorted to some kind of mud-throwing or rock-climbing activities. The dreaded Marc Surer was eventually the victim of a plot that had Cheever sweeping up the inside of the first corner on the track, a right which encourages demon manoeuvres up the inside to overtake. Both Cheever and Surer had found the astonishing limit of BMW adhesion (most of the cars have Goodyear rubber: Schurti and Ickx both ran Dunlop). Thus when Cheever touched Surer, it was pretty certain somebody would go off. That is just what happened. Surer found the Armco on the outside of the track, but re-started to finish fourth, a lap down on Cheever, Winkelhock and Ickx.
It hadn’t been a classic race in any sense. There was enough to hold the interest–particularly on the technical side in the paddock where the Renault F1 car’s absence swung frustrated engineers off in pursuit of touring car innovations –but it’s difficult to see any nation, apart from Germany and the USA, being seriously interested in running such expensive saloon/sporting GT races. The three factories –Porsche, BMW and Ford –seem as enthusiastic as ever about the championship, though it should be noted that both Ford and BMW had previously expressed their dissatisfaction with the series by withdrawing when Porsche were admitted with the turbo car in the bigger class. Previously the saloon car protagonists had fought their battles with drivers such as Mass and Struck in 24-valve six-cylinder coupés. For a national championship, the Germans have a real winner. Anywhere else in the world it would be impossible to find the combination of cash and engineering ability. It will be interesting to see how things develop: at present it looks as though, whatever you run, it had better be turbocharged. - J.W.