In telephone conference calls Dec. 14 and 18, the committee continued its work to draft an API SN category for ballot. API SN will be an upgrade of the current API SM category, identified by the API Donut trademark. It is intended to address the full spectrum of engine oil viscosity grades, including those not covered under the ILSAC specification, such as SAE 10W-40.

In addition the committee is working on a ballot for an “SN Resource Conserving” category, to replace today’s SM Energy Conserving designation. Subject to committee approval, these new categories will be balloted immediately, with an eye to commercial introduction in the fall.

For the new API SN category, the Lubricants Committee proposed, engine oil performance requirements will follow the same pattern as earlier API S category upgrades and their GF counterparts. That is, all engine oil performance parameters for both the API and ILSAC categories would be equivalent, except that SN does not include fuel economy as measured by the Sequence VID test and wear as measured by the Sequence IIIGA test on aged oil.

In addition, some bench tests are not required in API SN or their limits are somewhat relaxed. There is no phosphorus maximum (although there is a 0.06 percent weight minimum), nor are there any limits for sulfur content. Finally, there is no requirement for phosphorus retention.

The proposed API SN Resource Conserving category is somewhat more demanding. API has determined that along with improved fuel economy, these engine oils must offer greater engine durability and emissions system protection. In order to recognize these added requirements, the term “Resource Conserving” has been introduced to replace “Fuel Economy.”

The SN Resource Conserving category includes all of the remaining performance requirements of ILSAC GF-5 including the Sequence VID, except for the TEOST 33 high-temperature deposit test and the low-temperature gelation index. Limits for the TEOST MHT-5 deposit test are relaxed to 45 mg maximum (versus the GF-5 limit of 35 mg). Oils meeting these requirements will be able to display “Resource Conserving” in the bottom half of the API Donut, and SN in the top half.

Provided the API SN and API SN Resource Conserving categories are balloted successfully, they will begin licensing on Oct. 1, 2010. However, oils which already meet the requirements of SN or SN Resource Conserving may be labeled as API SM or API SM Energy Conserving beginning Jan. 1, since the new category is backward compatible.

The Vote on GF-5
The final tally was 10 approved (two with comments, one of them largely editorial) and two abstentions on the GF-5 limits proposed by the ILSAC/Oil Committee, which represents both oil marketers and automotive manufacturers.

Shell (approved with comments) and Infineum (abstained) said that a GF-5 category reference oil should be made available. Both believe that SAE XW-20 grade oils’ performance in the Sequence VID test for fuel economy and the Sequence IIIG for weighted piston deposits are important reference points. (ExxonMobil abstained based on the same concerns.) If a reference oil meeting only one of the test requirements — fuel economy or piston deposits — were used to calibrate engine test stands, it would be difficult to tell if the results were affected by changes in test severity.

A category reference oil helps solve this, by meeting all requirements for the given standard. It allows anyone to test for severity shifts in specific tests or test stands. It also helps reduce the risk that candidate oils may be rejected or approved by mistake.

On the question of text language for GF-5 to be included in API Document 1509, which governs the engine oil licensing system, the vote was 12 approvals (one with comments) and one abstention.

Shell expressed some interest in developing Sequence VID limits that would correlate to current GF-4 limits, which are based on the Sequence VIB test. ExxonMobil abstained, due to the proposal that GF-5 oils may enter the market labeled as GF-4 oils beginning Jan. 1, 2010. The company would prefer to see that date be pushed off to June 1. It feels that an orderly changeover to GF-5 oils will not occur if some products are marketed too soon as “meets the requirements of GF-5,” and dilute the Oct. 1 launch.