Oil Pumps for Wet and Dry Sump Porsche Engines

Prior to the introduction of the Mezger engine, the 547 “Fuhrmann” engine provided dry sump lubrication to ensure proper lubrication under all operating conditions. Engines including the pushrod horizontally opposed engine found in the 356/912, 914/4, and inline and V engines found in front engine 924 and subsequent models, feature wet sump engines. Where dry sump engines store oil in an external tank and whose oil systems are generally more complicated, wet sump engines store oil in the bottom of the engine (sump). Wet sump engines are the most common type found in modern production engines worldwide because of simplicity.

Porsche Boxster, Cayman, and 911 engines including the M96/M97 and 9A1/9A2 feature an "integrated dry sump", which in layman’s terms means these engines are wet sump. For example, in the M96 engine, camshaft driven scavenge pumps in the cylinder heads help to return oil back to the sump and the engine’s primary oil pump that is directly driven off the intermediate shaft via a hex drive that provides pressure to all oil lubricated engine components.

Both aircooled and watercooled Mezger engines features a dry sump lubrication system; the Mezger engine’s dry sump pump resides in the bottom of the engine and is driven off the intermediate shaft, which has oil-fed plain bearings on both ends. In a dry sump system, oil is stored externally. The oil tank also provides for oil de-foaming, ensuring oil supplied to the engine is thoroughly de-aerated under all operating conditions. Oil is filtered on the return (low pressure side) prior to entering the oil tank with a full-flow filter (no internal bypass). On 993 models, a secondary oil filter is used to protect the hydraulic lifters from fine particulate matter.

In the Mezger engine, the pressure side of the oil pump feeds all the main and rod bearings, chain tensioners (on models with hydraulic units), camshaft spray bars (and hydraulic valve lash adjusters, aka lifters in the 993), and piston squirters. The scavenge side of the Mezger’s oil pump returns oil from the crankcase to the external oil tank or sump.

In 2009 when Porsche released the 9A1/MA1 engine, the intermediate shaft was eliminated which means the oil pump is now driven off the crankshaft via a small chain. This new variable demand oil pump controlled by the DME provides improved scavenging and increased pressure under all operating conditions even with an "integrated dry sump" wet sump oil system. Oil starvation and pressure drops common to the previous generation of M96 and M97 engines are no longer an issue with the 9A1/MA1 and subsequent engines based on this new engine design. Starting in 2014, the 9A1-based 991 GT3 engine added dry sump lubrication with an external oil tank.

Porsche Oil Cooling

Keeping your oil cool is one way to improve oil pressure in your aircooled or watercooled engine. The ideal oil temperature is 215-225F, however without added oil cooling, it is often difficult to maintain these oil temperatures on any Porsche engine.

On aircooled Porsche 911 models without engine mounted oil coolers or those with front or fender mounted oil coolers, an external oil thermostat ensures rapid engine oil warm-up. A thermostatic switch is used on models with supplemental oil cooler fans to further assist with oil cooling. Additional oil coolers or upgrading old coolers with modernCSF oil coolers can assist with reducing oil temperature.

Modern watercooled Porsche engines utilize an oil to water heat exchanger that uses engine coolant to help warm up oil faster and stabilize oil temperatures, however additional cooling is often needed in hotter climates or if the vehicle is tracked. Larger heat exchangers can be fitted to most models along with upgradedCSF radiators, including a center radiator, to help reduce coolant temperatures, which has a direct effect in reducing engine oil temperatures.

The addition of a deep sump provides added oil volume on wet sump engines. The added oil volume also further reduces oil temperatures and also provides protection from oil starvation that can lead to catastrophic engine damage from loss of oil pressure due to oil starvation when tracking Boxster, Cayman, and 911 models with the M96/M97 engine.

Improving Engine Oil Pressure

As pressure is resistance to flow, using a larger oil pump to increase volume is commonly done to increase oil pressure in both aircooled and watercooled Porsche engines. Most engines feature a pressure relief (or bypass) which consists of a piston and spring that when a certain maximum oil pressure is met, the piston moves and can allow some of the oil from the pressure side of the oil pump to bypass the pressure circuit and return to the sump. On the VW Type 4/Porsche 914/912E engine, both larger oil pumps and high pressure oil pressure relief pistons can be fitted to increase overall oil system pressure.

Likewise, on the M96/M97 engine, Porsche released a revised 997 oil pressure relief spring and piston to help boost oil pressure which is an upgrade we recommend for all M96/M97 Boxster, Cayman, and 911 engines.

On aircooled Mezger engines, a common upgrade is to use a GT3 engine oil pump orAuto Verdi’s billet GT3 oil pumps. Auto Verdi offers a four stage pump like what is found in the 2011 Porsche 911 GT3 RS 4.0 engine.

Full Flow Oil Filtration

Even though already fitted with a spin on oil filter which provides superior oil filtration compared to a VW Type 1 engine, a popular upgrade for VW Type 4 and Porsche 914/912E engines is to modify the oil system to external full flow filtration. This ensures 100% oil the engine’s oil is filtered and also provides the opportunity to install a remote oil filter and oil cooler.