Engine Lubrication: Description and Operation
Lubrication System
The new 911 Turbo features a completely redesigned oil supply.
This is characterised by the following items:
- Integrated dry-sump lubrication
- A total of 7 oil pumps
- Electronically demand-controlled oil pressure pump
The main difference from the previous models is in the dry-sump lubrication. In the previous models, a separate engine oil tank ensured a sufficient oil supply, even in the case of high lateral and longitudinal acceleration. In the new 911 Turbo, this task is performed by dry-sump lubrication integrated in the oil pan. This design also ensures a sufficient oil supply on race circuits, both when standard tires and sports tires (Ultra High Performance - UHP) are used.
Compared with the dry-sump lubrication with separate engine oil tank used in the previous models, the integrated dry-sump lubrication in the new 911 Turbo has the following advantages:
- Integrated dry-sump lubrication
- Reliable oil supply, even on race tracks when using standard and sports tires (UHP)
- Low weight
- Lower engine and vehicle centre of gravity
- Reduced drive power of the oil pumps
- Lower system weight and therefore lower vehicle weight
- Lower engine center of gravity and therefore lower vehicle center of gravity
Instead of the 9 oil pumps used in the previous models, the new 911 Turbo has a total of 7 oil pumps for a reliable oil supply. All extraction points in the cylinders and turbochargers have been retained. By integrating the dry-sump lubrication into the oil pan and omitting the separate engine oil tank, it has been possible to also omit two extraction pumps from the crankcase of the new 911 Turbo. These were needed in the previous models to pump the oil from the crankcase to the separate engine oil tank. Omitting these oil pumps reduces the weight and eliminates the requirement for drive power for these pumps. This in turn reduces fuel consumption and exhaust emissions.
The new 911 Turbo therefore has a total of 6 extraction pumps (previous model: 8) and one oil pressure pump as before. They are divided into 4 oil extraction pumps for the cylinder heads (2 per cylinder head), 2 oil extraction pumps for the turbocharger and one oil pressure pump.
The new oil pressure pump is an electronic demand-controlled oil pump designed to reduce the drive power and churning loss.
Another modification concerns the location of the oil extraction pumps for the cylinder heads. In the previous models, these were located directly on the cylinder heads. In the new 911 Turbo, the pumps are integrated in the extraction pump module in the oil pan. This helps to further lower the engine's center of gravity.
The compact oil supply of the integrated dry-sump lubrication has also enabled a reduction in the oil filling quantity of the new 911 Turbo from approx. 11.0 l to approx. 10.4 l (first filling). This measure helps to reduce weight compared with the previous model for a total weight saving of approx. 8.8 lbs (4 kg) in comparison to the oil supply with separate engine oil tank, primarily by omitting the separate engine oil tank and the 2 oil extraction pumps.
Another advantage is the engine's much lower center of gravity. In the previous model, the separate engine oil tank was an upright container mounted in front of the engine on the right in the direction of travel. Its center of gravity was significantly above the crankshaft. In the new 911 Turbo, the container for the oil of the integrated dry-sump lubrication is in the oil pan beneath the crankcase and therefore well below the crankshaft. Relocating the oil tank for the dry-sump lubrication has lowered its center of gravity by approx. 30 cm. This enables a lower engine center of gravity and therefore a lower vehicle center of gravity, thereby enhancing driving dynamics.
The compact design of the oil pan has allowed the ground clearance in the area of the engine to be adopted unchanged from the previous model, despite integration of the dry-sump lubrication function. Compared with a conventional oil supply with pressure-fed lubrication and a simple oil pan, the oil pan in the new 911 Turbo is a complex component. It serves as the oil tank of the integrated dry-sump lubrication and has a partition box and an additional separator plate (watertight sheet metal panel) between the crankcase and the oil pan. This largely separates the two spaces and reduces both the churning loss in the crankcase and oil foaming in the oil pan, supported by two horizontally arranged air-oil separators (swirl pots).
Main changes compared with the 911 Carrera models:
The principle of the integrated dry-sump lubrication in the new 911 Turbo is basically adopted from that of the current 911 Carrera models.
The following features have been enhanced for the new 911 Turbo compared with the current 911 Carrera models:
- 2 additional extraction pumps for the turbocharger
- Larger oil/water heat exchanger
- Control adaptation to the demand-controlled oil pump
- Positive crankcase ventilation including adaptation to the additional bearing ventilation of the turbochargers
Compared with the 911 Carrera models, the modular oil pump module in the oil pan has been extended by two stages for extraction of the turbocharger oil. In order to cope with the higher engine power and to avoid critical oil temperatures, the power of the oil-water heat exchanger in the new 911 Turbo has been increased from 25 kW (911 Carrera) to 40 kW. The control of the demand-controlled oil pump has also been modified. This now features map-specific adjustment of the oil pressure to the higher bearing and piston loads of the new 911 Turbo. Like its predecessor and the current 911 Carrera models, the new 911 Turbo also features piston spray cooling.
Oil Circuit
