The Dutch engineer Witteveen made himself known at Sachs, then Gilera, and then by considerably improving the Yamaha engines used in Grands Prix in the Bimota frames designed by Massimo Tamburini and then driven in 250 and 350 cm3 by Randy Mamola, Jon Ekerold, Michel Rougerie, Marco Lucchinelli, and Eric Saul, among others.
The success was such that Ivano Beggio, the President and son of the founder of Aprilia, recruited him to head the competition department of the Noale manufacturer. Jan Witteveen, at the head of “Reparto Corse” from 1989 to 2004, brought the brand more than 120 GP victories and 23 World Champion titles.
Jan was asked why Ducati chose a V4 for the World Superbike Championship, over the inline 4s from BMW, Honda, Kawasaki and Yamaha. In MotoGP, Aprilia, Ducati, Honda and KTM use a V4, unlike in-line engines from Suzuki and Yamaha.
“An important point is the cost. The V-engine is more expensive because you need the camshaft control system twice. With the inline engine, you can control all four cylinders with just one, explained the Batavian technician to Ivo Schützbach from Speedweek. com.
“The advantage of the V-engine is that you can use a larger airbox and it's closer to the intake tracts. This makes the airflow almost straight, which is not possible with an inline engine, so it has a lower fuel-air fill. »
“The V-engine is also narrower, which makes it more aerodynamic and gives you more power. The in-line engine is easier to build. It requires fewer parts, so it is cheaper, but has aerodynamic disadvantages due to its width. »
“Another advantage is that when using a counter-rotating crankshaft, the gyroscopic effect is greater than with a V-shaped engine, the forces from the wheels, rotating " forward ", are therefore partially canceled. »
Superbikes do not have the same requirements in this area as MotoGP which, according to Witteveen, “ fight with too much power ". In addition, the concept of the complete range being marketed plays a decisive role for Superbikes. “Honda had V4 engines in the production range, but they are all gone. The Japanese are very cost oriented, especially Honda. Honda wants to produce cheaply and maintain a low selling price, while maintaining a certain profit margin. »
“Most motorcycles in the 1cc sports segment are sold by BMW,” says Witteveen. “ They do it well and keep their concept with the in-line four-cylinder. Additionally, the Superbike World Championship now allows technical solutions that are prohibited in the MotoGP category, such as variable intake control. »
“The problem is always the engine speed, so the control desmodromic valves from Ducati is a great advantage. BMW may have gained a few hundred laps thanks to the ShiftCam system and its valve control, but they will never match Ducati's numbers. This system is particularly useful in the lower rev range. »
“As the rpm increases, the valve lift must be shorter, otherwise the valve springs start to beat. Up to 15 rpm this is possible with conventional systems, beyond that, no. »
Jan Witteveen
Photos © Ducati
