Making Sense of New Oil Specifications: GM dexos and API SN Plus

As engine-operating conditions grow more severe, so do the demands placed on your motor oil. New engine hardware such as turbochargers, direct injection and variable valve timing (VVT) place increased stress on your engine oil. This, in turn, has led to the introduction of more strict more oil specifications.

Here’s what we’re going to cover:

Improved fuel economy

Corporate Average Fuel Economy (CAFE) standards require a fleet-wide average of 54.5 mpg by 2025 in the United States (although the Trump administration is expected to relax those standards). To meet these requirements the automotive industry has focused on smaller, more fuel-efficient engines. In fact, by 2020, industry experts predict that almost every new vehicle will feature gasoline direct-injection technology (GDI). The vast majority will also be turbocharged (T-GDI).

Severe operating conditions

Smaller, more-efficient engines that make the power and torque of higher-displacement engines undergo more severe operating conditions that can lead to…

  • Severe engine knock, also called low-speed pre-ignition (LSPI)
  • Increased engine temperatures
  • Compromised fuel injectors
  • Increased wear and deposits if the oil isn’t up to snuff

The biggest motor-oil-related challenge on the horizon is LSPI, which can destroy pistons and connecting rods.

LSPILSPI, cracked pistons & rods

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 T-GDI 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.

Oil can help 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.

New oil specifications: GM dexos and API SN Plus

Next-generation motor oils need to pass an LSPI test to meet these new demands. General Motors was first out of the gate and required oils to pass its own LSPI test. The updated GM dexos1 specification (known as dexos1 Gen 2) took effect Aug. 31, 2017.

The new American Petroleum Institute (API) specification, API SN Plus, is slated to go into effect as early as May 2018. Lastly, the International Lubricants Standardization and Approval Committee (ILSAC), which for the most part mirrors/honors the API specifications, will have its GF-6 performance specifications set to take effect in mid-2019.

LSPI Chart

Relax…for now

For now, you don’t have to worry too much about LSPI. Your vehicle’s computer is programmed to avoid operating conditions that lead to LSPI. But, operating your engine under those conditions does promise fuel economy gains. And, once oils hit the market that combat LSPI, you can bet the vehicle manufacturers will reprogram their vehicles to take advantage in their never-ending quest for better fuel economy.

AMSOIL prepared for the change

We’ve already reformulated Signature Series Synthetic Motor Oil, XL Synthetic Motor Oil and OE Synthetic Motor Oil to address LSPI.

AMSOIL achieved 100 percent protection against LSPI in the engine test required by GM’s dexos1 Gen 2 specification.*

When the API SN Plus specification goes into effect, AMSOIL motor oils will be recommended for use where the API SN Plus is required.

Check out this page to learn more about LSPI.

*Based on independent testing of Signature Series 5W-30, XL 5W-30 and OE 5W-30 in the LSPI engine test as required for the GM dexos1® Gen 2 specification.

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Comments

    1. Hi Dennis,

      You’re perfectly safe using AMSOIL synthetic motor oil in your GM vehicle that calls for an oil that meets the dexos1 Gen 2 specification. Our oils meet or exceed the performance requirements stipulated by dexos1 Gen 2, and are backward compatible with GM dexos1. You can use it without fear of losing your new-vehicle warranty. If someone at the dealership or mechanic tells you otherwise, call us at 715-399-TECH and we’ll set the record straight.

      While AMSOIL synthetic motor oils meet or exceed dexos1 Gen 2 and are recommended in engines calling for that spec, they aren’t on GM’s list of approved oils for the simple reason that we refuse to pay GM the exorbitant fee it charges to appear on its approved list. Doing so would incur higher costs, which inevitably end up passed on to you. It would also allow GM access to our motor oil formulations and hinder our ability to adjust our motor oils periodically for better performance when new lubricant technology emerges. Simply put, we formulate for performance, not third-party approvals.

      Thanks.

  1. Will zinc/phosphorus again be decreased in SP motor oil?
    I can not beLIEVE they haven’t come up with a cat conv friendly substitute to protect the flat tappet cams on very old cars. Will i be able to use SP oil in a 60’s chevy 250 strait 6 motor or a ’74 pontiac 8:1 compression 400 cubic inch v8? Or should i go with high zinc oil like Brad Penn’s, a zinc additive?

    1. Joe,

      Call AMSOIL Tech Services at 715-399-TECH and they’ll be happy to provide product recommendations for your vehicles.

      Thanks.

  2. Hello Amsoil Team,

    Thanks for all the great products you have provided my family over the years, I know all of my long running engines and transmissions are a direct result of the fluids you provide. However, it is with great sadness that I might have to discontinue use of your products if the new DEXOS standards are not applied to your product lines.

    I recently purchased a new GM vehicle (2018 Equinox w/ 2.0T X-LGT engine) and they are really pushing the “DEXOS Approved” standards to comply with warranty and the maint schedule. I fear using Non-DEXOS approved fluids with this new, fragile turbo engine in case there is an issue, whether it’s the manufacturers fault or not.

    I’ve had many new vehicles in my lifetime, but this time the cost of failure would really be a tragic event (financially). Manufacturers are looking for any excuse in the book to deny a claim or refuse warranty coverage.

    So, please tell me that your new SS formulas (due out in Sept 2017) will come with the DEXOS Approved label so I can continue using your products!!!

    As always, THANKS!!

    Joe

    1. Hi Joe, thank you for your comment! The new AMSOIL formulations are formulated to meet and exceed the dexos1® Gen 2 specification. The approved emblem will not be on the front label, since our products are not licensed to the dexos1® specification, nor are they required to be licensed. It is not lawful for GM to deny OEM warranty coverage to someone using a non-licensed dexos1® product. AMSOIL uses specifications like dexos® as a minimum standard, then builds protection that goes beyond the minimum standard. This is why many of our product claims are based on dexos® standards, like the low-speed pre-ignition claim above in the post.

  3. Hi Amsoil team,

    The new, reformulated SS that you are about to introduce at the end of September – will it be immediately available to European distributors as well?

    My oil change will come up most likely around September/October time frame so I am wondering, if I should stick to the old SS this one time or hold off for the reformulated one?

    1. Hi Mick,

      Yes, when reformulated Signature Series Synthetic Motor Oil is introduced, it’ll be available to everyone. In the meantime, however, you’re perfectly fine using the current formulation.

      Thanks.

  4. Hi,

    Is Amsoil Signature Series (with such a high Calcium PPM number) safe to use in direct injection, turbo charged engines, like new Honda 1.5 turbo Civic?

    1. Hi Mick,

      Although calcium has quickly become known to the public as a potential promoter of LSPI, it is not the sole reason for its occurrence. Formulations contain a number of different additives that must be managed to control LSPI. That said, LSPI occurs in vehicles with a software update that will not take place until LSPI-promoting oils are cycled out of the marketplace. That said, AMSOIL Signature Series is perfectly safe to use in today’s turbocharged direct-injected engines.

      Josh

  5. When are you guys planning to come up with new formulation for SS oils? I’m currently using 0W20 SS in my Turbo 1.5DI and wonder how that high Ca is affecting my engine in terms of LSPI event frequency…

    1. Hi Sergey,

      Reformulated Signature Series Synthetic Motor Oil is scheduled for introduction in September, 2017. Check back here on the AMSOIL blog or amsoil.com for an announcement then.

      Thanks.

  6. What about Those new CVP transmissions Dana is about unleash. Will you have a CVP fluid for those?

    1. Hi James,

      We don’t have any current plans for a product for CVP transmissions, but if demand increases, we’ll certainly consider it.

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