About the importance of the correct oil pressure and the different approaches to the subject.

In motorsport, attempts are always made to increase the engine power and acceleration of the vehicle. Longitudinal and lateral acceleration forces exert pressure on the engine oil, moving it in the oil pan and pushing it into the crankshaft housing. The task of the oil pump is to supply the engine with oil, to ensure constant oil pressure and thus proper lubrication. The main problem, however, is that with conventional systems, the oil often cannot be constantly extracted from the oil pan. Modified oil pans with internal baffles can improve the oil supply, but in the extreme demands of motorsports this is often not sufficient. Dry sump systems provide a remedy here. The oil pump is installed externally, which means that a smaller oil pan can be used and it is possible to lower the engine’s center of gravity.

The advantage of this? Dry sump pumps have multiple suction and discharge chambers. The oil is thus not “only” pumped to the engine, but also “actively” extracted from the oil pan. Together with an externally installed oil tank, constant lubrication is thus achieved. In most cases, so-called 3-chamber pumps are used, which use two suction chambers to draw oil from the oil pan and then pump the oil to the engine via a pressure chamber. Oil cooler, external tank and oil filter are interposed. However, there are now also various special versions that have up to six or even seven chambers. Ideal for extreme high-performance vehicles or particularly large-volume models.

What are the alternatives? From a purely technical point of view, a dry sump system is always the first choice for motor sports cars. But if such a system exceeds the possibilities of the budget, or the regulations of the racing series prevent its use, then oil pressure accumulators offer a thoroughly interesting alternative. These accumulators work like batteries and perform several tasks: they supply the engine with oil pressure during cold starts and compensate for a possible loss of pressure when cornering with high lateral acceleration forces. These systems are based on a cylinder with an internal piston that is “preloaded” on one side by means of compressed air. On the other side of the piston, compression takes place via the engine oil pressure to operating pressure. In the event of a pressure loss (e.g. in curves), this pressure is released again. Such accumulators are inserted into the pressure side of the engine oil system. A check valve ensures that the pressure is only ever delivered in the correct direction, and a stopcock guarantees that the pressure in the accumulator is maintained when the engine is switched off, thus ensuring that there is sufficient pressure for cold-start assistance.

But beware: basic things related to the oil supply and the topics of oil pressure and oil temperature are often neglected. For example, adding an oil cooler inevitably results in some pressure loss. This is especially important for dry sump systems, which often operate with very high oil flow. The pressure drop is slightly higher for a cooler with few but longer rows due to the faster oil flow. Choosing a narrower cooler with more rows will maintain optimum pressure even with high oil flow. If the cooler is used for transmission or differential oil cooling, on the other hand, it makes sense to choose a cooler with fewer rows to speed up the oil flow.

One should also not underestimate the effect of good oil line routing. Ring sections, for example, save a lot of space during installation, but have completely different flow characteristics than pipe bends. The same applies to external dry sump tanks: good tanks have a sophisticated internal design that reduces foam and bubble formation, provides optimum ventilation and stabilizes the oil in the tank against centrifugal forces. And – last but not least – of course it also depends on the oil quality used. There are huge differences between the products on offer here and often even a simple oil change brings about a noticeable improvement. For motorsport and high-performance applications, we recommend the English lubricant specialist Millers Oils based on many years of experience.