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P1546 Hybrid Front Wheel Drive Touring Car Gearbox

The P1546 gearbox is a high performance Hybrid front wheel drive touring car gearbox that has been designed specifically for the 2022 British Touring Car Championship.

The P1546 makes use of the existing and well proven P1046 FWD BTCC specification gearbox, which has been adapted to fit the Cosworth developed TOCA hybrid system and is compatible with the currently homologated engines. The 50 volt hybrid system enables the driver to utilise a push-to-pass or defend functionality, giving a 15 metre gain per lap in a single deployment. Electric only running in the pit-lane is also available.

The 70 kW electric motor is integrated into the transmission, driving directly onto the input shaft, in a P2.5 configuration, with energy recovery achieved by harvesting the reverse torque from the gearbox to the electric motor, ultimately feeding back into the Delta Motorsport batteries. Gearing from the gearbox to the motor is through a 1:1 ratio, spinning the motor at the same speed as the four cylinder I.C. engine. Race-Tech Hybrid BTCC magazine article can be viewed via this link.

The gearchange system incorporates Xtrac’s polynomial barrel track design and low inertia gearchange rack to improve gearchange response and driver feel. The gears are arranged to allow the overlap of barrel track profiles. The low positioning of the gear cluster enables easy removal from the car under the chassis rail, and lowers the centre of gravity. The gear cluster is fully exposed when removed from the gearbox allowing quick inspection, and easy access for ratio changes.


  • 450Nm (332lbf ft) maximum input torque capacity
  • 70 kW axial flux synchronous motor driven through 1:1 gear train from input shaft
  • 6 speeds with sequential gearchange selection
  • Suits installations with gearbox on L.H. side
  • Aluminium L169 castings, with ‘O’-Ring face sealing
  • Lubrication is via single stage eccentric lobe pump, configured for use with an external cooler
  • Differential is an Xtrac cassette type plate unit with a choice of ramp angles, plate and preload settings. (Quick change diff cassette is easy to remove)
  • Bell crank actuated low inertia gearchange rack reduces wear and improves gearchange
  • Xtrac ’Pin pawl’ ratchet and pawl gearchange assembly with low inertia polynomial barrel
  • Left hand output flange is integral with the differential, to suit GI 82 size tripode joint
  • Clutch release slave cylinder (AP CP3859-1250)
  • Gearbox weight is approximately 39kg (86lb) – Excluding Electric Motor (+7 kg)

The Gearbox Offers The Following Benefits

  • Light, positive sequential gearchange
  • Easily removable cluster for ratio changes
  • Easily removable differential with externally adjustable differential pre load
  • Cost effective, reliable, lightweight solution

Option Summary

  • Cross shaft assembly
  • Super polished gear ratios (Xtrem Process)
  • Internally re-circulating oil pump system
  • In car gear lever
  • Gearchange potentiometer, mounting and display

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