The 8HP ZF automatic transmission has been an integral part of the BMW M235i Racing Cup since the 2014 season. For the forthcoming 2016 season, ZF is introducing the next evolution: the 8P45R motorsport transmission.
The 8P45R had its first successful track appearance at the VLN race end of October at the Nürburgring. ZF states that it has paved the way for automatic transmissions in motorsport with the 8HP during the 2014 season, with the automatic transmission allowing ‘drivers to stay almost completely focused on their environment and on the track.’ ZF claims that the risk of mechanical damage, as a result of mis-shifts is also excluded as are fatal blockages and dynamically unbalancing shocks on the driven axle.
The 8P45R’s redesign sees it gain new ratios, shift points and an improved shift speed. By omitting the 8HP’s converter and other reduction measures, ZF claim a 15% weight reduction. The previous unit’s internal power losses were also reduced.
The design retains the fundamental design and assembly scheme of the 8HP however, which comprises of four planetary gear sets and five shift elements. One of several new features is the omission of a converter in the transmission. The pulling away or drive-off process is implemented by internal shift elements. A vibration damper upstream from the transmission input prevents damage through engine oscillations. The gear ratio spacing is closer and the rev drops between gears have been reduced. Only the first six gears of the former 8HP transmission were used when racing. In the new transmission all eight gears are utilized.
ZF plans the transmission’s market launch in the second quarter of 2016. Initially, the 8P45R transmission is exclusively available for the BMW M235i Racing. The company states that it also envisages its use in other manufacturers’ competition cars.