Sauber GP bike run in public at Sepang

NIALL MACKENZIE gave the new Sauber-Petronas four-stroke GP machine its first public outing on the eve of the Malaysia GP at Sepang.

The Scot completed a couple of slow but impressively noisy laps on the three-cylinder bike, called the GP1.

Although not granted a place on the new combined four and two-stroke grid in 2002, the bike has certainly already won the decibel wars. The sound was less complex than the Honda V5 seen at the Twin Ring Motegi GP in Japan two weeks ago.

Mackenzie confirmed he’d been taking it easy – barely leaning off the machine in the corners. “If I’d dropped it, they’d have thrown me off the top of the Petronas Towers, ” he quipped.

The engine was limited to 13,000rpm and it proved a challenge keeping it off the rev-limiter, which would have caused an unimpresive popping and banging.

“It picks up the revs so quick from 10,500 that it’s hard to catch it, ” added Mackenzie, who is due to stay on after the Malaysian GP on Sunday for further tests, during which the rev ceiling will be raised to 16,000rpm.

After the roll-out, Petronas chief engineer Osamu Goto described the changes to the Mk2 engine, compared with the Mk1 motor shown at the first GP of the year at Suzuka.

The biggest change has been a switch from pneumatic valve springs to conventional steel items. ” To make 220 horsepower, which is what we believe is necessary, you don’t need such high revs, and steel springs are sufficient, ” he said.

The cylinders are also no longer vertical, but canted backwards by a couple of degrees. This has improved the intake path, Goto added, and ” makes it easier to adjust the engine position. ” . The Sauber motor has forward-facing air intakes, with the exhausts running straight out the rear.

The new engine is also 55mm smaller than the first motor, criticised for its tall appearance. The reduction has come half from the cylinder head, and half in the block.

Goto reiterated his reasons for choosing three cylinders. ” Ten kilos, ” he said (10kg is the weight limit difference between three and four/five-cylinder designs).

” Honda and Yamaha are wrong, ” he added. ” They have commercial reasons for their decisions, where we are able to think only about the technical reasons. ”