Engine TechThe buzz since the season opened in Australia is how much power the BMW engines were producing. Pitlane gossip pegged the number at 850 bhp, a few stronger than Ferrari and well up on the backsliding McLaren Mercedes engine.
The decline in power and reliability of McLaren's Ilmor-designed Mercedes engine surprised fans, but insiders knew the team would be directly affected by the ban on the use of beryllium for 2001. Beryllium is an element that is both strong and light, perfect for pistons in high-revving engines. But it is also incredibly toxic and expensive, so the teams decided it would be in their common interest to ban its use.
BMW didn't use any beryllium in its engine last year, because it didn't want to pursue a dead-end technology, said Mario Theissen, BMW Motorsport Director. "When we designed the first engine, we knew already that it would be banned for this season, and it didn't make sense to develop something for us to just throw it away after one season.
"I was indeed surprised by the setback McLaren was suffering from," he admitted. "[Ilmor engine designer] Mario Illien said it was mostly due to the beryllium ban. So it cost them. That was something which surprised me."
To make parts from beryllium requires strict procedures for handling the material, and the machine tools must be outfitted with vacuum equipment to prevent dust or shavings from escaping, so it is not an easy material to use. Between the difficulty of working with it, and the impending ban, what attracted Mercedes to the material?
"You have a lighter piston," said Theissen. "A lighter piston means higher revs." And revs, as we know, are the route to more horsepower when other avenues have been fully exploited.
So how is BMW able to make more power and rev its engine to 17,700 rpm (the typical redline in F1 these days) without beryllium? "To reach the same rev area without beryllium, with aluminum you need a different design," explained Theissen. "That's what we have done." He declined to elaborate on what is different about the design but did say that BMW uses only aluminum in its pistons and not some other exotic material that hasn't yet been banned.
Carbon-fiber pistons may appear to be attractive, especially to teams with budgets the size of top-tier F1 operations. Not so, says Theissen. Despite their light weight and lower requirements for lubrication, carbon fiber is too unpredictable a material for F1 engines, he said.
"The problem [with carbon-fiber pistons] is that you have to be absolutely failure-free, and process control with carbon-fiber parts is almost impossible," Theissen said. "So far, they are hand made. Each part is different."
Nevertheless, more power is available within the current engine specification, Theissen said. "If you keep these engine regulations for another 10 years, it might be possible to reach 1,000 horsepower. It won't necessarily take 10 years to get there, but I think more than 5."
How will teams get there? It is those revs again. "To achieve 1,000 horsepower you have to go beyond 20,000 rpm, and that is the reason for me to say that it is not possible in the short term."
Benetton/Renault is the only team to have really taken significant risks this season with its engine design, and through most of the season it appeared their gamble was a dismal failure. The company's wide-angle V10 was intended to help their car's handling with a lower center of gravity, but the engine was beset by problems, primarily a significant power deficit.
"It is an interesting concept, but it is difficult to really achieve much because the main-and I would say only-advantage you can get is the lower center of gravity," Theissen said. "The disadvantages are lower stiffness of the vehicle/engine structure and the biggest problem is vibrations caused by this engine."
Most teams use either 90-degree V-angle engines, or 72-degree engines. The 90-degree engine is better balanced and has a lower center of gravity, but the 72-degree layout produces evenly spaced firing pulses. Renault's engine is said to be 110 or 111 degrees, though the company will not confirm the angle.
"If you go beyond 90 degrees you get very strong vibrations. This requires a stronger and heavier rear wing beam, which eats up the advantage of the lower center of gravity." How much could a flatter engine help a race car's handling? "It is next to marginal," said Theissen. "It is hard to calculate because it depends on the track."
Seems likely. But on the other hand, Benetton has shown impressive form late in the season with a design that is early in its development cycle.