By Gabe Rhoads
General Manager, Consumer Engine Lubricants

The solution that OEMs have demanded is at hand, with API SN Plus, the supplement to API SN and ILSAC GF-5, arriving not a moment too soon. This new requirement ensures that lubricants providing low speed pre-ignition (LSPI) mitigation performance have already begun to arrive on the market, with bottles specifically labelled for use in Gasoline Direct Injection (GDI) engines populating shops around the globe.

API SN Plus represents much needed progress for a lubricant industry that has been wrestling with ongoing test development issues for ILSAC GF-6, the next major engine oil specification. Marketable LSPI protection can’t wait any longer.

There’s more to this story, though. Our industry has been working to find the most effective LSPI solutions for several years, but the reality is that LSPI is a relatively new phenomenon within a certain set of new, still-evolving engines. And there is not necessarily widespread consensus on what, specifically, is the most effective solution for high LSPI performance.

But one thing is for sure, and it shouldn’t be overlooked: LSPI durability is a critical performance factor.

API SN Plus delivers LSPI performance to the marketplace by means of the Sequence IX test. The test is a result of significant work on the part of the broader lubricant industry, and it’s a major milestone. However, the Sequence IX test only evaluates the LSPI performance of a fresh lubricant.

As engines and lubricants advance, drain intervals are becoming longer. The lubricant industry must be sure we’re delivering all the necessary performance and protection over the course of the entire drain interval—including critically important LSPI mitigation.

At Lubrizol, we’ve been hard at work investigating the degree to which LSPI protection changes over time, and which additive solutions ensure long-term LSPI durability. Members of our research and development teams have recently published a paper in SAE International comparing a number of solutions; here’s an excerpt from the abstract:
“To quantify LSPI durability, an engine test methodology that evaluates LSPI on fresh oil, then ages the oil using a relevant duty cycle, then finally re-evaluates the aged oil for LSPI propensity was developed. Using this three-part testing protocol, four different oil formulations were evaluated. Results show that some formulating strategies work well for LSPI prevention only with fresh oil, while one prevents LSPI when fresh and aged.”

We believe that this is important work, and as we continue to develop a better understanding of LSPI and how to stop it, the industry will need to continue evolving its approaches. The evolving nature of our LSPI understanding once again highlights the lubricant industry’s need for rolling, adaptive new test development on an as-needed basis.

Our view: The lubricant industry has the responsibility to deliver solutions to OEM and consumer needs—and LSPI durability is just as important, if not more so, than initial LSPI performance.

With API SN Plus, the lubricant industry has delivered a needed win. But as we continue to better understand LSPI, we need to continue delivering better solutions—not stop with the first one that shows promise.

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