Sauber's 16.000-Rpm Triple Ready To Rock!
SAUBER'S 16.000-RPM TRIPLE READY TO ROCK!
ROUNDUP
SAUBER’S NEW 968CC Mk. II Triple made its racetrack debut last October at the Malaysian Grand Prix. Its three high-revving cylinders filled the air with a shattering four-stroke howl.
The maker’s full name is Sauber Petronas Engineering, which is a Malaysian-backed, Swiss-based engineering company that has been active in Formula One. The company has developed the 93 x 47.5mm engine for the stated reason of showcasing SPE’s engineering. It is, in effect, three cylinders from a 3-liter F-l V-IO car engine, packaged for motorcycle use. Former 500cc GP rider Niall Mackenzie rode the reportedly Harris-framed prototype, with revs limited to 13,000 rpm.
SPE’s famed Japanese engineering chief, Osamu Goto, was originally with Honda’s F-l program, then moved to Ferrari and is now with Sauber. Why a Triple, rather than a Four like Yamaha’s YZR-M1, or a V-Five like Honda’s RC21IV?
“Honda and Yamaha are wrong,” Goto said, indicating that these designs are overweight and commercially motivated. It has been obvious from the start that production machines would be spun off from the Japanese four-stroke GP bikes. “We were able to think only about the technical reasons (for design),” Goto continued, noting that extra cylinders will cost those makers more than 20 pounds. Don’t more and smaller cylinders mean higher revs and more power? Goto asserted that more than 220 horsepower (“What we believe is necessary.”) would be superfluous.
Because the Kenny Roberts team also receives support from Petronas, a Southeast Asian oil company, rumors marry the Sauber engine to a future KR chassis. Not so, says Roberts, insisting that Team Roberts is an engineering company and would build its own four-stroke engine if the need arose.
Although information about F-l engines is intentionally vague, assertions that more than 800 bhp is now available from the best designs are viewed more as inert gas than fact. A more realistic figure would be 750, so three cylinders might make 225 bhp. Those aspiring to enter MotoGP now have the example of the 190-bhp Yamaha, which has lapped faster as its peak power was reduced and its powerband reshaped to control wheelspin. Only Honda is still confidently talking about 248 bhp. The pivotal issue is the control of wheelspin during off-corner acceleration, and Goto’s remarks show that he knows races aren’t won in dyno rooms.
The Mk. I Sauber Triple was tall at 22 inches. Assembled in September, 2000, and dyno-run the following December, it revved to 16,000 rpm and developed some 200 bhp at 15,000 rpm. The 120-degree crankpin arrangement yields a powerful rocking motion that required a balance shaft. To allow operation at 18,000 revs, the Mk. I version employed pneumatic valve closers in place of metal springs. Now that power has been demoted, the pneumatic closers have been replaced by conventional coil springs, and engine height has been cut by 2 inches. Four narrow-angle radial valves are used in each cylinder.
The engine’s three large oval intake stacks face forward at a 42-degree downdraft angle. In the latest version, the cylinder is slightly inclined backward to provide better packaging for the airbox. Mackenzie found the bike a handful. “It picks up the revs so quick from 10,500 that it’s hard to catch,” he said. Later, in a private Sepang test, revs were to be raised gradually to 16,000. Having missed the declaration date for next season, the Sauber will not be eligible to race until 2003.
Modulating torque to control wheelspin will be the central problem of the new 990cc fourstrokes. Yamaha hopes to achieve this with a negative-slope, dirttrack-style torque curve. The others may use electronics to prevent runaway spin, yet somehow retain throttle steering. It will be a battle of invisible technologies.
Kevin Cameron
