Difference between SL and SM ratings

[dsmith41]

In somewhat simple terms, could someone tell me the difference between the SL and SM API ratings?

Would there be a difference in performance in an engine manufactured in 2004 using an SL oil vs. a SM oil?

 

[Johnny248]

amount of zinc and phosphorus?

 

[ZZman]

Yes they lowered the amount of ZDDP to protect the emission system.

For all automotive engines presently in use. Introduced November 30, 2004. SM oils are designed to provide improved oxidation resistence, improved deposit protection, better wear protection, and better low-temperature performance over the life of the oil.

**Difference in performance......I say No.

 

[dsmith41]

Originally Posted By: ZZman
Yes they lowered the amount of ZDDP to protect the emission system.

For all automotive engines presently in use. Introduced November 30, 2004. SM oils are designed to provide improved oxidation resistence, improved deposit protection, better wear protection, and better low-temperature performance over the life of the oil.

**Difference in performance......I say No.


Okay, I suspected there would be little to no preformance difference.

So if ZDDP levels are down but the new SM oils are supposed to offer better wear protection, how is that? If remember correctly, ZDDP is an anti-wear additive. Did they increase other anti-wear additives to make up for the loss of ZDDP? What additives are up?

 

[heavyhitter]

Originally Posted By: ZZman
Yes they lowered the amount of ZDDP to protect the emission system.

For all automotive engines presently in use. Introduced November 30, 2004. SM oils are designed to provide improved oxidation resistence, improved deposit protection, better wear protection, and better low-temperature performance over the life of the oil.

**Difference in performance......I say No.


+1 here is your answer

 

[jorton]

Originally Posted By: ZZman
SM oils are designed to provide improved oxidation resistence,


And if I remember right, zddp is the antioxidant.

 

[heavyhitter]

Originally Posted By: dsmith41
Originally Posted By: ZZman
Yes they lowered the amount of ZDDP to protect the emission system.

For all automotive engines presently in use. Introduced November 30, 2004. SM oils are designed to provide improved oxidation resistence, improved deposit protection, better wear protection, and better low-temperature performance over the life of the oil.

**Difference in performance......I say No.


Okay, I suspected there would be little to no preformance difference.

So if ZDDP levels are down but the new SM oils are supposed to offer better wear protection, how is that? If remember correctly, ZDDP is an anti-wear additive. Did they increase other anti-wear additives to make up for the loss of ZDDP? What additives are up?


Yes ZDDP is an anti wear ad but it is a last resort additive. I your engine is pushed to the limit to use up all your ZDDP then you have A LOT more to worry about than if it is SL or SM rated.

 

[Audi Junkie]

Look at the spider graphs here:

http://www.lubrizol.com/EuropeanEngineOils/RelativePerformanceToolIntro.html

In the Passenger Oils under API specs.

Of course, different synth oils and blends can ~exceed~ the spec, it's really just for dino oils. That's the problem with API, nothing that indicates an extended drain oil, only the oems and ACEA do that.

 

[jorton]

Originally Posted By: dsmith41
Did they increase other anti-wear additives to make up for the loss of ZDDP?


boron
sodium
calcium

 

[ZZman]

I think with the better base oils and combinations they use and because if you increase things like better protection from oxidation and deposits your wear goes down.