The New API SN PLUS Formulation and Why You Should Care

When it comes to turbocharged engines, it's all about performance, which is why automakers are spearheading the newest supplemental motor oil specification - API SN PLUS - to protect against Low-Speed-Pre-Ignition (LSPI) - a condition found within Turbocharged Gasoline Direct Injection (TGDI) engines. LPSI occurs prior to spark ignition in turbocharged, downsized gasoline engines at low speeds and under high loads. It is considered to be a "premature combustion event" that can lead to high cylinder pressures resulting in heavy engine knock. In a video on knock by Engineering Explained host, Jason Fenske, he explains how "Engine knock, or pinging, occurs when a separate pocket of air-fuel mixture ignites after the spark has ignited the air-fuel mixture within the combustion chamber. (It) can be prevented using higher octane fuels, retarding ignition timing, or by using a lower compression ratio, among other solutions." The newest solution? API SN PLUS motor oils. 

Why the Formulation Change?

The industry was in need of the API SN PLUS supplemental motor oil specification to complement existing parameters and to address the growing impact of Low-Speed-Pre-Ignition (LSPI) - a common condition in TGDI engines who are highly susceptible to knock based on high pressures from turbocharging and direct fuel injection into the combustion chamber. It is believed that the primary culprit for LSPI is motor oil properties, and automakers have been eager to have a supplemental motor oil specification to combat the effects and protect turbocharged engines. The new specification - API SN PLUS includes additional testing for not only API SN, but an extra test for LSPI.

Does Your Vehicle Need API SN PLUS Oil

By reading your owner's manual for your vehicle you can ascertain whether or not your engine is turbocharged and requires API SN PLUS. Not all engines require the additional protection against knock, idle stop and Low-Speed-Pre-Ignition (LSPI), but many products now either meet or exceed API SN standards to offer the widest spectrum of protection for consumers. An SCL consultant can assist you in understanding whether or not your engine requires API SN PLUS, it's benefits and potential hazards if not implemented.

The Bottom Line

With the ever increasing desire to boost fuel economy while adequately meeting emissions standards, automotive and lubricant technology continues to evolve. Automakers and OEMs are asking more and more from lubricants to perform better while simultaneously offering top-of-the-line engine protection. Enhancing the performance of your engine and protecting against conditions like idle stop, Low-Speed-Pre-Ignition (LSPI) and turbocharging is a top priority. That is why automakers are driving the implementation of the new API SN PLUS as a supplemental motor oil specification. Over time, as specifications change, formulations change and technology changes, SCL will be here to keep you informed about what you need to optimize your engine's performance and prolong engine life.