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SN PLUS

WHAT YOU NEED TO KNOW ABOUT

TECHNICAL BULLETIN

First, why did the API decide to release SN Plus ahead of the impending GF-6

update?

API SN Plus was proposed by ILSAC on July 20, 2017 and reviewed further by the industry at the API

LG Standards meeting on Aug 15, 2017. With delays in test stand development for ILSAC’s new

GF-6 performance category, GM found it necessary to release an improved engine oil specification to

address a newly discovered phenomena found in Turbo Gasoline Direct Inject (TGDI) engines called

Low Speed Pre-Ignition (LSPI). After delays in developing their own LSPI test stand, GM released the

dexos 1® Generation 2 specification in 3rd Qtr 2017. The next generation additive system showed

improvements in fuel economy, engine cleanliness, and included a new direction chemically in the

detergent system that drastically reduces occurrences of LSPI. As dexos 1® licensed engine oils,

they are recommended for use in GM automobiles. The increasing impact of LSPI left the other

OEM’s scrambling for a solution of their own. This prompted original equipment manufacturers

(OEMs) to request immediate implementation of a supplement to ILSAC GF-5 to protect turbo

gasoline direct injected (TGDI) engines from catastrophic damage. The proposed API SN Plus

supplement is not a new category and will be available alongside the current API SN and ILSAC

GF-5 categories. This unprecedented request from OEMs highlights the severity of low speed

pre-ignition (LSPI) and confirms the immediate need for higher performing lubricants to protect

against damage.

What is GF-6 and why has the test development process been so

complicated?

In 2012, the International Lubricants Standardization and Approval Committee (ILSAC) announced

they were working on a new PCMO engine oil specification to replace the current GF-5. This

specification had a planned release date of January 1, 2015 and was intended to Increase Fuel

Economy, Enhance Oil Robustness, Expand Overall Fuel Efficiency, Improve Wear Protection, and

Reduce Engine Aeration. Complications arose while developing the new engine tests as at least 3 new tests are expected to address Fuel

Economy, Wear, Oxidation & Piston Deposits, and Sludge & Varnish Formation. The new tests were needed to not only address the upgrades in

engine technology, but to also be viable for evaluating the new lower viscosity grades. These lower viscosity grades (0W-16 and below) will be

identified as GF-6b while the normal viscosity grades (0W-20 and up) will be identified as GF-6a. Finding a chemical balance that provides

adequate protection across all viscosity grades has shown to be a challenging task. What an oil needs to perform in low temperatures can be

the same components that produce ash in high temperatures and vice versa. Holistic solutions have been required to provide the robust

protection required in tomorrow’s engines.

Will Smitty’s and CAM2 offer products labeled as API SN Plus?

Yes, in an effort to remain at the forefront of passenger car lubrication, we will offer a full line of products fully licensed against the API SN Plus

supplement. These offerings and their expected date of availability will be:

0W-16 SN Plus 5/1/18 5W-20 SN Plus/ GF-5 6/1/18

0W-20 SN Plus/GF-5 dexos 1 5/1/18 5W-30 SN Plus/ GF-5 6/1/18

0W-30 SN Plus/ GF-5 5/1/18 10W-30 SN Plus/ GF-5 6/1/18

5W-20 SN Plus/ GF-5 5/1/18 10W-40 SN Plus 6/1/18

5W-30 SN Plus/ GF-5 dexos 1 5/1/18 20W-50 SN Plus 6/1/18

10W-30 SN Plus/ GF-5 5/1/18 SAE 30 / SAE 40 SN Plus 6/1/18

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Does my car require SN Plus engine oil?

Unless your automobile recently drove off the assembly line, it’s doubtful you will require the protection provided by the SN Plus

supplemental category. Although with the number of TGDI engines in service growing by the minute, you could see SN Plus oils

recommended with your next purchase.

What is LSPI?

LSPI is the spontaneous ignition of the fuel/air mixture before spark-triggered

ignition. It is another version of pre-ignition. Pre-ignition (engine knock) has

been around since the beginning of internal combustion engines. LSPI,

however, occurs under low-speed, high-torque conditions, such as taking off

from a stoplight in TGDI engines. This scenario can create conditions where

the fuel/air ignites too early in the combustion cycle, throwing off the engine’s

timing. The expanding combustion charge collides with the piston as it’s

moving up the cylinder, potentially destroying the pistons or connecting rods.

Can engine oil prevent LSPI?

Experts suggest the cause is due in part to oil/fuel droplets or deposits in the

cylinder igniting randomly. The droplets and deposits contain enough heat to

ignite the air/fuel mixture before spark-triggered ignition. Oil formulation can play a role in reducing LSPI. Certain motor oil

ingredients can promote LSPI, while others can help reduce it. It’s tempting to think, “Well, dump a bunch of ingredients into your

formulations that help reduce LSPI.” But some ingredients that help reduce LSPI have been limited over the years in motor oil

formulations for other reasons. It truly is a scientific balancing act confronting oil formulators. It’s no easy task to formulate motor

oils that deliver excellent wear protection, resist the increased heat of turbocharged engines, prevent deposits, act as a hydraulic fluid

and, now, combat LSPI. The performance of the entire formulation – not just one or two ingredients – is what counts.

What is the consequence for not using a SN Plus rated oil where required?

LSPI, or super knock, can lead to catastrophic damage to pistons and rods leading to very expensive repairs. LSPI events are known

to happen at random and in series with each other giving little warning to the driver. SN Plus rated products from Smitty’s and CAM2

provide the protection required to eliminate LSPI occurrences.

WHAT YOU NEED TO KNOW ABOUT(continued)

TECHNICAL BULLETIN

FuelInjector

PreIgnition

Intake Valve Exhaust Valve

CamShaft

SparkPlug Cam

Shaft

Piston

Air

LSPILow Speed

Pre-Ignition