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7 stricter quality criteria for ILSAC GF-6 - the latest quality specification for engine oils.

Typically, car users distinguish engine oils by their viscosity (e.g. 5W-30, 0W-20 or 5W-40), considering this parameter as a quality indicator. This is not a sufficient factor to justify the compatibility of the oil with the engine. That's why quality standards are listed in the vehicle's owner's manual. These standards are defined by international automotive associations: the European ACEA, the American API and the Japanese-American ILSAC. The latter is very often used by Japanese and Korean manufacturers. ILSAC has been improving and tightening the requirements in its quality specifications for over 30 years. To obtain ILSAC, the oil undergoes several laboratory and dyno tests on 5 different engines. ELF presents 7 more stringent requirements according to the ILSAC GF-6 vs GF-5 specifications, which very well illustrate the increase in the technological level of current engines and lubricants.

The graphic above shows the evolution of the ILSAC association's oil standards GF-6 versus GF-5. The corners of the individual areas (purple, green and orange) illustrate the 7 criteria. These are the increase in viscosity, the impact of the oil on driving economy, maintaining engine economy, preventing the formation of high-temperature deposits, oil evaporation, timing chain wear and the occurrence of the LSPI phenomenon.

The difference between these requirements for the GF-5 standard (green) and GF-6 (orange) shows the incredible technological development of combustion engines over the last few years, and the resulting increase in requirements for the oils used.

1. Increase in viscosity

Nowadays, the use of dowsizing has become very common. Smaller engines achieve high power. This means an increased thermal load on the oil. The oil then tends to oxidize and increase its viscosity. This requirement significantly limits the possibility of viscosity increases, which must mean the use of better base oils, antioxidant additives and soot dispersion additives.

2. Driving economy

The purpose of oil is to reduce friction in the engine. The use of appropriate viscosity, friction modifiers and a reduced HTHS coefficient will contribute to reducing friction in the engine and increasing its efficiency, which translates into lower fuel consumption.

3. Maintaining engine economy

Here, an important criterion tightens the requirements that despite long and hard engine operation, oil meeting the latest GF-6 standard should still ensure the reduction of fuel consumption.

4. Preventing the formation of high-temperature deposits

Carbon deposits are specific types of high-temperature deposits. For obvious reasons, the most exposed places in the engine are around the piston rings and around the exhaust or turbo valves. In this case, appropriate quality oils can also limit this phenomenon.

5. Oil evaporation

The latest GF-6 standard ensures the lowest oil evaporation from the combustion chamber. This reduces contamination of the intake and exhaust valves and the catalytic converter.

6. Timing chain protection

In the case of chain timing drives, the chain is lubricated with engine oil, which must also ensure its protection, cooling and cleaning. For example, soot, which is also produced in direct injection gasoline engines, tends to settle in various places in the engine, including: just on the timing chain. This is particularly harmful in the area of the pins connecting the chain links, because it causes them to wear out, which in turn leads to an increase in chain’s length.

7. Protection against LSPI phenomenon

An increasingly common problem faced by combustion engine designers is the phenomenon of LSPI pre- ignition. This phenomenon has become particularly intense with the advent of downsizing and direct injection technology in forced induction (supercharged, turbocharged) gasoline engines. It can most often be observed in the low speed range (1500-2000 rpm), with a heavy engine load and a high charge. Premature ignition is caused by, among others: unburnt fuel and glowing oil particles present in the combustion chamber. LSPI results in the piston skirt hitting the cylinder liner, which leads to serious engine damage. Oils that reduce the LSPI phenomenon have a formula that limits the formation of the above-mentioned particles, which can glow inside the cylinder and additionally have an extinguishing effect on the fuel diluted in the oil layer on the liner or piston rings.

The latest ILSAC GF-6 standard is divided into two types: GF-6A and GF-6B. The ILSAC GF-6A standard (e.g.: ELF Evolution FULL-TECH VSX 0W-20, ELF Evolution FULL-TECH VCX 0W-20, ELF Evolution 900 USX 5W-30) is characterized by: - backward compatibility with older engines - greater ability to mitigate LSPI phenomena - good economy of engine operation (VIE tests). The GF-6A standard is used in SAE viscosities 0W-20, 5W-20, 0W-30, 5W-30 and 10W-30. For XW-20, minimum HTHS = 2.6; for XW-30, minimum HTHS = 2.9*

The ILSAC GF-6B standard (e.g. ELF Evolution R-Tech ELITE FE 0W-16) is characterized by: - no backward compatibility with older engines - greater ability to mitigate the LSPI phenomenon - good economy of engine operation (VIF tests) This standard is only applicable in SAE 0W-16 viscosity with a minimum HTHS = 2.4 *.

Published on 11/09/2023
1 min reading time

New engine design solutions, exhaust emission standards, and increased amounts of biocomponents in fuel have resulted in very stringent requirements for the quality of engine oils over the last few years. When selecting engine oil, relying solely on oil viscosity is no longer sufficient. It is very important to check the vehicle's user manual or the oil manufacturer's website (https://elf.com.pl/dobierz-olej-0) what is the required specification or approval of the oil and select the appropriate oil that meets a given standard. Without it, we will not only shorten the engine's life, but may also lead to its rapid destruction by the dangerous LSPI phenomenon. Andrzej Husiatyński, TotalEnergies Technical Department.

*HTHS – (High Temperature High Shear) is a measure of dynamic viscosity at 150 degrees Celsius at very high rpm's. The shear resistance of the oil film is measured. The lower the HTHS, the lower the resistance. This translates into higher engine efficiency and lower fuel consumption. However, a smaller HTHS also means a „thinner” dynamic oil film. Therefore, the engine's design (fits, oil pump, roller pushers, etc.) must be adapted to low HTHS. The oil must be enriched with additional surface-active anti-wear additives. Low HTHS oils are not backwards compatible with older approvals and engines.