‘Dedicated racing oil can improve the engine’s performance, and increase protection too’
Nowadays lubricants are a liquid construction and design element in modern internal combustion engines. With a dedicated racing oil formula, you are able to improve the overall engine performance and protection, the two basic criteria to finish the race on the top of the podium. And this is what race engineers around the world really appreciate, but how does it work?
The right blend
Basically, the two main components of engines oils are the base stock and the additive package. This is also valid for racing engine oil formulations.
With the right choice of base stocks combined with the dedicated additive package you can achieve a big advantage – optimised performance and protection. At full throttle, the racing oil formulation in the lubrication circuit is permanently under high thermal, mechanical stress and pollution. The quality of the base stock in combination with the additive package has a big impact on the condition and performance of the engine oil during the race. During operation the viscosity of the lubricant is affected by three criteria:
shear stability
fuel dilution
temperature
A very shear stable formulation is crucial to maintain viscosity and at least oil pressure during the race. With the right pre-choice of viscosity grade you can compensate the income of unburned fuel, which is diluting the engine oil. This is absolutely crucial for engines running with an enriched air-fuel ratio at full engine speed. The temperature aspect can be also covered by the choice of the right viscosity grade. The higher the number of the high-temperature viscosity grade the higher the viscosity and oil pressure at high temperatures.
Feel the force
But how do you gain more power output by the lubricant? In the internal combustion engine, we have approximately 10% of friction losses indicated from moving parts in the lubrication circuit and the lubricant itself. If we are able to reduce these internal friction losses, we recover mechanical energy and increase the power output. To optimise this we need to know the more detailed friction losses distribution at different operating modes and where we have the highest friction losses, eg at 1,000rpm in idling mode 45% from friction losses coming from the piston, piston ring and cylinder liner, another
30% from the timing system, 10% from the crankshaft and con-rod bearings, 8% from the oil pump and 7% from others. But, at idling, you will not win a race.
At 6000rpm the distribution of friction losses looks totally different: 40% coming from the crankshaft and con-rod bearing, that means four times higher, another 35% from piston, piston ring and cylinder liner, just 10% from the timing system, 10% from the oil pump and 5% from others.
Bearing friction losses are four times higher at high engine speed therefore the right lubricant can reduce the bearing losses. By using a lubricant with a low-traction coefficient, the internal friction losses can be reduced and mechanical energy can be recovered.
This can bring up to 7.2 horsepower more, as proved in a test performed on a 3.6-litre Porsche Cup racing engine.
Turn on the heat
Thermal stability is another key criterion for racing oils. At high operating temperatures, the lubricant is evaporating. The lower the evaporation loss of the racing oil formulation the lower the internal oil consumption of the engine.
This has been tested with a 24-hour engine bench test and the oil consumption for 24 hours (more than 3000 miles) was just 0.6 litre per hour. The combination of best performing synthetic base oils including esters, which provide a polarity effect, ensure optimised lubrication even at extremely high operating temperatures (oil temperature up to 150-160 °C in peaks). The polarity effect improves the heat transfer and reduces the oil temperature. Furthermore wear and tear during the cold start is reduced as well.
Finally all components of the formulation – base stock and additive package – interact with the surface during the operation either to protect or enhance performance, make movement easier. This material surface of the lubrication circuit is constant and not expandable. The balance of base stock and additives is carefully adjusted according to the technical constraint related to the application and has significant impact on the overall performance of the racing lubricant as well.
For nearly 50 years Motul has been mastering top oil formulations. The current 300V Motorsport Line is based on ESTER Core technology and provides a variety of viscosities for all engines.