What is the difference between API SP and SN engine oils?

[MacAdriel]

The differences between API SP and SN engine oils lie in their phosphorus content and respective advantages. Specific details are as follows: Different phosphorus content: The thickness or viscosity (phosphorus content) of engine oil varies at certain temperatures. SN engine oil has relatively lower phosphorus content. Comparing the viscosity of SN and SP oils, SP has a slightly higher viscosity value. Different advantages: SP oil forms a stronger oil film than SN, providing better protective performance. Additionally, SP offers stable improvements over SN in terms of noise reduction, fuel consumption, and acceleration performance. Notes: For most vehicles, SM grade engine oil can generally meet daily needs. M-grade engine oils feature better oxidation resistance, deposit control capability, and superior anti-wear protection, ensuring fuel efficiency and long-lasting performance. When purchasing engine oil, you can also refer to the vehicle's user manual to determine which lubrication standard should be followed. Simply choose engine oil from reputable manufacturers that meets the specified standards.

[VanOwen]

The main difference between API SP and SN lies in performance upgrades. API SN is the motor oil standard introduced in 2010 and used for many years, while SP is the updated version from 2020 designed for modern engines. SP enhances protection against low-speed pre-ignition (LSPI), especially for turbocharged vehicles, preventing piston damage. It also improves fuel efficiency and extends the lifespan of emission systems like GPFs while reducing carbon deposit buildup. SP has stricter testing requirements, including new wear protection and cleanliness tests, ensuring better stability and durability under high temperatures. For daily driving, newer cars or turbocharged models should prioritize SP, though older vehicles remain compatible. Overall, SP offers greater reliability and peace of mind—like a software update patch.

[McRuth]

When it comes to engine oil API SP and SN, I find it quite practical for daily oil selection. The SN standard is older, and many cars still use it, but the newer SP has advantages: SP provides better protection against low-speed issues in turbocharged engines, reducing the risk of sudden knocking. Additionally, it helps save a bit on fuel costs and protects the vehicle's exhaust system from clogging easily. When changing oil, it's important to note that SP can be used in older cars requiring SN, but not the other way around. So, for newer cars, it's best to opt for SP-grade oil. The price difference is minimal, and spending a little extra for long-term engine health is worth it.

[MacManuel]

From driving experience, the difference between SP and SN engine oils is quite significant. Previously, SN seemed sufficient, but SP has changed the game: SP addresses turbocharging issues in modern cars to prevent unexpected pre-ignition that could damage the engine; testing standards have been tightened to ensure the oil doesn't fail during long trips or under high temperatures. In practical oil changes, SP is compatible with older vehicles but offers better protection, like upgrading airbags.