Stateside: IMSA sportscars

Bruising encounters

The three opening rounds of the IMSA Camel GT Championship in the United States took TWR Jaguar’s John Nielsen to the top of the drivers’ championship placings, and demonstrated to the Porsche teams that their strongest challenge for years will come from Britain 1988.

Ever since the Porsche 962 reached the USA midway through the 1984 season, victories have been shared among teams owned by Al Holbert, Bruce Leven and Rob Dyson, with only minor interference from the quick but generally unreliable Nissan and Chevrolet GTP entries.

Passing the winner’s parcel has become a habit, but the Tom Walkinshaw-directed Castrol Jaguar team earned a very fine victory at Daytona, beautifully paced over 24 hours after an early setback with the XJR-9. Nielsen was in the winning crew, and at Miami a month later he was beaten by 0.004 seconds at the end of a three-hour street fight, narrowly won by Price Cobb and James Weaver in the Dyson Porsche.

The Sebring 12-Hous in March was not quite such a success for Jaguar, for Martin Brundle retired after the first hour with an overheated engine and the second car lost time due to a collision, then a broken pinion in the gearbox. Nielsen transferred to the lamed XJR and finished in seventh place overall, though sixth in the GTP category, and his nine points were just enough to maintain his advantage over Hans Stuck and Klaus Ludwig, winners of the 12-Hours.

IMSA rules allocate an extra five points for results in the “endurance” races at Daytona and Sebring, but normal Can-Am scores (20-15-12-10-8-6-4-3-2-1) are attached to to the remaining eleven rounds, and the Dane’s slender points advantage might lengthen as the two Germans, Stuck and Ludwig, miss events due to clashing commitments.

Ludwig took Texaco Havoline sponsorship to Leven’s team for the first three rounds of the year, but will have to miss four races giving priority to the Texaco-backed Ford team in the European Touring Car Championship; Struck’s main programmes this year are with Audi in the Trans-Am series and with Porsche in the German Supercup.

In the normal course of events Holbert, Dyson and Leven would expect to share their victories, and while that would help Porsche to retain the manufacturer’s championship (after three rounds Porsche led Jaguar by 55 points 41) their contest could easily let Nielsen, Brundle, Davy Jones or Jan Lammers forge a lead in the drivers’ championship for Jaguar. It is hardly likely that Walkinshaw expects to lift both titles in his team’s first US season and the manufacturers’ would be the more difficult, but one would do very nicely!

What is rather worrying for Jaguar is the way power is restricted this year. A 6-litre limit was imposed on stock-block engines such as it’s V12, while the turbocharged engines were throttled by a 57mm restrictor upstream of the single blower. As a result the Porsches, the Nissan and the Corvette will enjoy a power advantage of perhaps 20 bhp, but more importantly (as Porsche and Jaguar drivers agree) the Stuttgart engine has considerably better torque characteristics than it had last year. Hitherto the flat-six had comparatively poor torque and a bad throttle delay, but masses of power at the top end; now it has torque and immediate response, but something under 700 bhp in race trim.

Significantly, FISA has just decided that the turbo engines will have 57mm restrictors in the 1989 World Sports-Prototype Championship, reduced to 55mm (as originally proposed for 1989) in 1990. Silk Cut Jaguar established a very clear advantage over the Porsche customer teams in 1987, but has a much stronger challenger in the Sauber-Mercedes this year and retention of the World Championship is by no means assured. In 1989 the World Championship rules will be similar to, if not identical with, IMSA regulations . . .

Jaguar’s V12 will be restricted to 6.0 litres and 620 bhp, the Mercedes 5.0-litre V8 will have 57mm restrictors and so too will Porsche’s V8 “Indy” engine in a new chassis. Porsche might have reigned supreme in Group C between 1982 and 1986, but someone in Paris seems determined to see that Jaguar’s reign will be shorter. It will not have escaped Walkinshaw’s attention that the Group C rules allow twin turbo-chargers, and the benefit of low-speed throttle response.

So far, the Nissan and Chevrolet GTP entries have been eclipsed in IMSA, although Geoff Brabham took the Japanese-engined car to a stunning pole position at Miami, a full two seconds quicker than Hans Stuck’s Porsche.

The Nissan is prepared and entered by Electromotive, a Californian company run by Don Devendorf and John Knepp, and little of the Lola ancestry remains in the 1988 model; the aluminium honeycomb chassis has been designed by Trevor Harris and built by Jim Chapman, the 3-litre V6 engine has an aluminium-alloy block (instead of cast-iron), and the car will be handled all season by Brabham and John Morton.

The Nissan has a history of being blindingly quick in qualifying over the past two seasons, but has won on only one occasion at Miami in 1987. Electramotive passed up the two early endurance events this year and, after starting from pole at Miami, coped with serious brake problems to finish eighth.

Sarel van der Merwe became so disenchanted with Rick Hendrick’s “works” Chevrolet Corvette GTP (another Lola chassis model) last season that he came close to leaving the scene. The GM engine-management system was underdeveloped, and the V6 turbo-powered car was so heavy on fuel that it usually needed an extra pit-stop.

That problem seems to have been cured this year, and a second car is available with a Ryan Falconer-tuned 5-litre V8 engine; it will, soon, have the Lotus-developed active-suspension system which was seen late last year. Neither Chevrolet showed great speed at Miami, Elliot Forbes-Robinson/David Hobbs qualifying the turbo-engined car ninth, then breaking its gear-lever in the race, and van der Merwe/Bobby Rahal qualified eleventh then retired with a broken throttle-linkage.

The Ford GTPs, formally called Probes, are now privately owned by Tom Milner and although they look like concours winners they lack speed, and have endemic piston failures.

Surprisingly perhaps, Pontiac lay third in the GTP manufacturer’s category with eight points from three races, thanks to the excellent Spice chassis constructed at Silverstone. After a fitful year in the Lights category last year (when Don Bell and Jeff Kline won on eight occasions yet failed to take the title from Jim Downing, who had a single victory in his Mazda-Argo) Pontiac moved into the top class with two cars. Spice Engineering has supplied a modified SE88 chassis for Pontiac’s 4.5-litre V6 engine (the car is driven by Steve Durst and Mike Brockman) and a new chassis for the 5-litre V8-powered Pontiac Firebird which made its debut at Miami in the hands of Bob Earl and Jeff Kline.

As yet the cars are new, but Durst’s Pontiac finished eighth at Daytona and seventh in class at Sebring, and Earl’s was tenth at Miami. With Spice director Jeff Hazell working hard in the background, it is possible to imagine Pontiac emerging as the third force in GTP, to vie with Jaguar and Porsche. And if that were the case, look no further for Spice Engineering’s Group C1 World Championship contender in 1989.

At times last year the GTP grids fell to as low as nine cars, and even the wealthy Americans complained about the cost of competing in the 16-round series in a continent larger than Europe. But the early rounds of the 14-event 1988 championship have been well supported by up to eight “customer” Porsches two or three TWR Jaguars, Pontiac, Ford, Chevrolet, Nissan and Buick (the latter supplying engines to Gianpiero Moretti’s Momo March team) and the coming season could be the best for some years.

In the Lights category Jim Downing will not yield his title without a fight. He has won the title three years in succession with his Mazda twin-rotor-powered Argo – in 1985 with eight class wins, in 1986 with four, and last year with just one victory but a strong of good placings.

Pontiac’s star performers have moved up to the GTP class, but here are plenty of customers to take their place, now using the more powerful 2.7-litre Cosworth four-valve-head four-cylinder engine. In the early rounds, though, honours have been shared by the Tom Hessert/Dave Loring Essex Tiga team, and by Gaston Andrey’s Ferrari team.

Hessert and Loring achieve much more success than Howden Ganley’s Tigas enjoy in the World Championship, winning the Lights class at Daytona and at Sebring, and finishing second at Miami. However, at Daytona they ran a 3-litre V6 Chevrolet engine, and subsequently they used a similar 3-litre V6 Buick; since points are awarded to the manufacturer of the engine, they have been overhauled by Andrey, who has a Ferrrari V8-powered Alba AR3 for Martino Finotto/Ruggero Melgrati (class winners at Miami) and a Tiga GC286 with similar power for Uli Bieri and Angelo Pallavicini (second in class at Sebring).

That may sound confusing, but it means that Hessert and Loring are well ahead in the drivers’ championship, but the Ferrari marque narrowly leads Buick and Mazda in the manufacturers; championship.

IMSA also admits GTO and GTU special saloons (over and under 3-litre capacity), categories which are keenly contested by exciting Chevrolet Corvettes and Camaros, Lincoln-Mercury XRTis (like Sierras, but with turbo and V8 engines), and triple-rotor Mazdas which go like the wind with speedframe chassis and Kevlar bodies – so there is far more variety than we are accustomed to seeing in the Silverstone 1000km, for instance.

There is, too, far more traffic. Seventy-five cars started at Daytona, and while veterans such a Derek Bell and Al Holbert move easily through the pack, the Castrol Jaguars have already had a number of bruising encounters. That has to be put down to experience, but it makes the outcome much more of a lottery than Walkinshaw is accustomed to.

Still, he can take heart from the fact that Holbert’s usually-dominant Porsche team has made a poor start to the year, retiring at Daytona and Sebring with engine failures and finishing only fourth in Miami. So far, while Stuck and Ludwig have made the best start to Porsche’s year, Price Cobb and
James Weaver appear to have the most stamina. MLC