Cycle News - Archive Issues - 2000's

Inside Sauber By nationalities working together in a very international company. It was new project leader Luca Guerciotti, an Italian from Alfa Corsa, the racing branch of Alfa Romeo, who described the process that had led to the choice of an in-line three-cylinder motor as the most suitable for a GP motorcycle. The team had considered five options: 60-degree V-twin with balance shaft; 90-degree V-twin (like Ducati); in-line triple; in-line four (like Yamaha); V-four (like Suzuki). They had included a V-four 500cc two-stroke and a World Superbike 1000cc twin for comparison. Factoring in the relevant minimum weights under the regulations, the engineers used telemetry data and computer simulations to map out the potential strengths and weaknesses of the motors in nine areas they considered key to ultimate performance as a potential race winner, including: MICHAEL SCOTT " n II the technology we use will ..... come from the Ferrari Fl engine. This three-cylinder motor is basically three cylinders of the VI0 motor. " With these words, the experienced and widely respected racing engineer Osamu Goto ushered in the Fl era of motorcycle Grand Prix racing. The new four-stroke GP class may not yet have an official name, but it has power, and plenty of it, from impeccable sources. And this particular new 16,OOO-rpm 200-horsepower triple will be ready to go racing next year. Just two things are missing - a chassis, and a team to run it - and Sauber-Petronas will be making an announcement on details of their entry for next season before the end of this one. Goto was speaking at an exclusive briefing for selected pressmen, at the immaculate Sauber Petronas headquarters outside Zurich in Switzerland. Just across the road was the Sauber Fl workshop, from where the most successful "non-factory' team in car racing operates (behind only big hitters Ferrari, Maclaren-Mercedes and Williams-Honda). Sauber Petronas Engineering (SPE) is an offshoot, owned 60/40 b5' Sauber and Malaysian oil giant Petronas. And they are eager to make their name in the 'competitive and profitable world of racing design and construction on two wheels as well as four. The GPI engine is their second finished product. They already run an FI engine, last year's Ferrari VIO, though in fact the motors go back to Italy for rebuilds etc; and they have built a slave V -twin motor which is two cylinders of this FI engine, and acts as a test rig for various technologies, such as pneumatic valve operation, variable-length intake systems and the use of new materials. Festooned with sensors, it still looks like it would be one heck of a cruiser motor, Harley-style, but capable of approaching 20,000 rpm. They have also built on spec a car-racing engine - a four-cylinder, two-liter turbo dubbed the EOL Their baby now is the racing triple for bikes, currently under intensive final development. Five engines have already been built, and run on their two dynamometers. A big reason for inviting the press was to gain publicity. "We have built this motor with the intention of selling it,' confirmed management spokesman Paul Fricker, himself an ex-Cosworth man originally from Britain, one of several 40 OCTOBER 10. 2001 • cue 1 . POWER TO WEIGHT Internal friction is an important factor, and the V-four engine lost points because of the need for separate cam-drive gear trains for each bank; although overall the four-cylinder configuration was the best. 2 . APEX TO APEX Simulations measured not only the elapsed time on a simulated pair of consecutive bends, but also speed after four seconds and top speed attained. Using existing data, wheelspin could be predicted and taken into account. The elapsed time saw the triple and the fours almost equal; the in-line four marginally quickest after four seconds, from the triple and the V-four; and also fastest in overall top speed. Surprisingly, the current 500cc two-stroke fared rather badly in this simulation, victim of its relatively narrow power band, and requiring one extra gear change as a result. Wheelspin simulations showed, not unexpectedly, that the 500 twostroke suffered the most problems, and the in-line four was almost as bad, with the triple better and the Vtwins untroubled. 3 . ENGINE WEIGHT Although overall minimum weight is specified in the regulations, the lighter the engine, the more latitude designers have in other areas. Naturally, the 90-degree V-twin was best, the requirement for a balance shaft spoiling the game for the 60-degree V-twin. Add the exhaust, hoy;ever, and the triple's simple and light three-into-one system made it almost equal to the best. I • nlll_s Sauber Is planning on running Its three-eylinder four-stroke In next year's Grand Prix Series. (Below) The triple sits next to a current Yfour two-stroke. WIth exhausts, the two-stroke weighs gS.8 pounds; the Sauber tourstroke engine _Ighs 110 pounds. They also considered how amenable the engine layout was to shifting the position and the weight forward, which is the usual goal in racing bikes. Here the V-twin and Vfour layouts fell short, where the inline triple and four were the best. Relative to the two-stroke 500, overall weight is surprisingly similar. With exhausts, the two-stroke tipped the scales at 96.8 pounds, the SPE triple at 110 pounds. 4 - CRANKSHAFT HEIGHT AND WIDTH The placement of the heaviest component of the engine is important for weight distribution, and is deter- mined to a large extent by its width each end must allow a 60-degree lean angle with the suspension fully compressed. The triple engine and the 60-degree V-twin were about equal on height, with the width of all the V-engines dictated by the gearbox, the triple a little wider, and the fours the worst. 5 . ENGINE OVERALL HEIGHT AND SIZE The tallest engines were the V-twin and the in-line four, rather surprisingly, the triple coming in next, and the V-four the most compact. The impact is on aerodynamics, with the in-line four recording the worst drag figures.

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