What is the difference between SP and SN engine oil?
2 Answers
Engine oil SP and SN differ in terms of grade, oil film, protective performance, and phosphorus content. Below is the relevant information about engine oil: Differences between SP and SN engine oil: Engine oil serves functions such as lubrication and wear reduction, auxiliary cooling, sealing and leak prevention, rust and corrosion protection, and shock absorption. The grades of SP and SN engine oil are different: SP is currently the highest grade for gasoline engine oil; SN is the second grade. Oil film: SP has a stronger oil film; SN's oil film is relatively weaker. Protective performance: SP offers stronger protective performance; SN's protective performance is average. The thickness (phosphorus content) also differs, with SP engine oil having slightly less phosphorus content, which can reduce damage to the three-way catalytic converter. In terms of noise reduction, fuel consumption, and acceleration performance, SP engine oil generally shows stable improvements over SN engine oil. Can SP and SN be mixed? Different grades of the same brand of engine oil should not be mixed. SP and SN contain different types and proportions of additives. Mixing them may cause chemical reactions under high temperatures in the engine cylinder, leading to reduced lubrication effectiveness and potential engine damage.
Engine oil standards are constantly being updated, with SP being the successor to SN, primarily designed to protect newer generation engines. My car is turbocharged, so I pay special attention to this. SP is significantly better than SN in terms of resisting low-speed pre-ignition, which prevents sudden knocking in the engine during low-speed, high-load conditions—this can cause serious engine damage. Additionally, SP offers upgraded protection for timing chains, reducing wear and extending chain life. In terms of cleanliness, SP provides superior deposit control, helping to reduce carbon buildup. Many China VI vehicles now recommend using SP-grade oil, especially those with turbocharging or direct injection technology. Although it's a bit more expensive, the long-term benefits for engine health are worth it. Since switching to SP in my turbocharged car, I've noticed a clear improvement in idle stability.