Porsche 911 Turbo User Handbook Manual page 17

Lightweight design. rods. For optimum durability, we've
used forged aluminium pistons
The six-cylinder boxer engine is a running in Nikasil-coated aluminium
compact unit offering excellent liners and cooled via individual
cylinder charging and torque-curve oil-spray jets. The results: lower
characteristics as well as first-rate frictional resistance and a lengthy
balance with minimal vibration. service life – even when subjected
The alloy crankcase consists of to heavy use.
two main sections, each containing
one bank of cylinders. The crank- The cylinder heads are made
shaft runs in eight main bearings from an extremely heat-resistant
and is driven by forged connecting lightweight alloy. Each cylinder
bank has two overhead camshafts
driving a set of four valves (two
inlet and two exhaust) on each
individual cylinder. The valves are
arranged in a 'V' formation and
have a highly efficient dual-spring
closing action enabling higher
engine speeds. Performance is
enhanced with the aid of both
Variable Turbine Geometry (VTG –
see page 42) and VarioCam Plus
(variable valve timing and lift on
· 40 ·
the inlet side – see page 48). The
benefits are not only greater power
and torque, but also better fuel
economy and lower emissions.
Dry-sump lubrication.
This racing technology uses a
separate oil reservoir to ensure
consistent oil pressures throughout
the engine, even during prolonged
periods of lateral load.
After passing through the engine,
every drop of oil is returned
directly to the external reservoir.
The flow is driven by two scavenge
pumps in each cylinder head by means of a dedicated oil-feed
and a further two pumps in the pump. With a further scavenge
crankcase. Gas is removed from pump in each of the twin turbo-
the returning oil by means of a charger units, the 911 Turbo has
defoaming device in the reservoir. a total of nine separate pumps
As a result, the oil level in the driving the lubrication system.
reservoir remains virtually constant
at all times. The oil is returned to The oil level can be checked from
the lubrication points in the engine inside the car via the standard
911 Turbo |
Main rotating assembly and valve gear
on-board computer. This solution
is not only cleaner and more
convenient than a conventional
dipstick, it is also much more
accurate.
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Drive