Porsche 911 Turbo User Handbook Manual page 14

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1. Oil scavenge pump
2. Oil pressure pump
(obscured)
3. Engine oil reservoir
(dry-sump lubrication)
4. Camshaft adjuster
Lightweight, high strength.
(VarioCam Plus)
5. Intake camshaft
Compared to conventional
6. Tappets (with hydraulic
engines of similar displacement,
valve clearance adjustment)
the 911 Turbo engine has a
7. Valve springs
wondrously compact design.
8. Intake valves
Its two banks of cylinders are
9. Nikasil-coated cylinder bore
located on a horizontal plane,
10. Forged aluminum piston
lowering its center of gravity.
11. Forged connecting rod
This "boxer" cylinder arrangement
12. Crankshaft
also provides good balance and
13. Camshaft drive chain
reduced vibration.
14. Camshaft drive chain
tensioner with guide rail
Its compactness is complemented
15. Single-spark ignition coil
by lightweight materials. The
16. Spark plug
crankcase, for example, is a
17. Exhaust-gas turbocharger
lightweight alloy constructed in
with Variable Turbine
two main sections, one for each
Geometry (VTG)
bank of cylinders. The pistons are
18. Exhaust system
aluminum. The cylinder heads are
19. Catalytic converter
made from a lightweight alloy
20. Pressure pipe
which is extremely resistant to
21. Throttle valve (electronically
high temperature.
actuated)
22. Plenum chamber
Frictional resistance is also notable.
23. Ancillary drive belt
The pistons run in Nikasil-coated
24. Fluid reservoir for
aluminum liners, featuring
power-steering system
individual oil-spray cooling.
As in all 911 engines, dry-sump
The 911 Turbo I Performance
lubrication ensures consistent
oiling. Vibration is further minimized
by a crankshaft running on eight
main bearings.
Each bank of cylinders 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" configuration and feature a
highly efficient dual-spring design.
These time-proven elements
of Porsche engine design
provide the ideal platform
for performance-enhancing
technologies, such as VarioCam
Plus and Variable Turbine Geometry.
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