Valve Drive

Valve Drive







The new 911 Turbo uses a rotary-vane vane actuator, familiar from the 911 Carrera, for continuous adjustment of the intake camshaft. The adjustment range of the actuator is 40° crank angle.

The small valve lift was increased from 3.0 mm to 3.6 mm in order to make more efficient use of the advantages of VarioCam Plus with continuous camshaft adjustment and a larger adjustment range compared with the 911 Turbo (996) with respect to consumption, output and exhaust emissions. The large valve lift was left at 10.0 mm.

Valve Springs

The exhaust backpressure is also increased as a result of the increase in the boost pressure in order to achieve higher torque and power output in the middle rev range. The valve spring assembly was modified in order to ensure that the exhaust valves are reliably closed.

This was achieved by a progressive design without increasing the friction losses or producing excessive pressure at the contact point between the cam and tappet.

Flat-base Tappets

The shape of the hydraulic tappets on the exhaust side has been optimized by providing them with a reinforced base while leaving the overall weight unchanged in order to guarantee the service life of the tappets.

Camshafts

The camshafts and timing have been optimized for the new engine.







Timing in retarded setting at 1 mm valve lift and zero play:

Intake opens, large stroke 20° before TDC
Intake closes, large stroke 50° after BDC
Intake opens, small stroke 30° after TDC
Intake closes, small stroke 30° before BDC
Exhaust opens 40° before BDC
Exhaust closes 9° before TDC







Chain Drive

The timing chains have been lengthened by two chain links compared with the previous engine in order to compensate for the thermal expansion of the engine. As a result, it was also necessary to adapt the guide rails and chain tensioners.

Vacuum Pump

Similar to the current 911 generation, the new 911 Turbo also has a mechanically driven vacuum pump that uses rotary vane technology. This replaces the conventional vacuum amplifier to provide the vacuum for the brake booster and for activating various switching valves. It is located on the cylinder head of cylinder bank 1-3 and is driven by the corresponding exhaust camshaft.