Other observations about SP - they use a 2.0 EcoBoost Ford (obsolescent) to test timing chain wear. That engine never really had issues with “chain stretch” which is a colloquial term for chain wear causing timing to fall out of specification. The 3.5L V6 GTDI was the engine notorious for this!
You have to grasp that the standard 3.5L Ford engine had no such issues! It was naturally aspirated, most versions were still using port injection, and it spec’d 5W-20 oils.
Due to the lack of VIIs in 5W-20s on average, compared with 5W-30 oils - the High Temperature Full Shear was typically higher - M1, for example - in their SN formulation - the 5W-20 is near 2.1, while the 5W-30 is near 1.9. The 5W-20 is actually thicker at full temporary shear of the VII @ 302F. This seems like a small amount, a couple tenths - but you are talking about a 10% difference in the film thickness.
From there, you add in that the GTDI is probably seeing about 10X the fuel dilution - 3-5%, instead of 0.3-0.5% - and the viscosity of that 5W-30 drops significantly more.
Let’s not forget that it also happens to be equipped with a couple of very hot, small, power adders, that increase Torque near exponentially - and you have a recipe for rapid chain wear!
And so - this was the contributing factor for the development of the ILSAC GF-6 requirements and incorporation into API SP testing. There are actually 2 categories of GF-6 that vary in their requirements…
GM, on the other hand - released a new 1.4L Turbocharged Direct Injected 4-cylinder in their small platform car - state of the art - going to be the most fuel efficient - and customers were easing them around town when Boom! Engine blown while gently cruising around town for groceries! WTH? Grandma wasn’t exactly redlining this thing for all it’s worth…
Well, turns out - under moderate loads, like climbing a hill in 5th or 6th gear, at low RPMs - something caused the fuel charge to detonate like a bomb prematurely - completely shattering the piston, and occasionally ventilating the block.
GM went back and did a lot of testing in the lab. They finally tracked it down to oil in the combustion chamber being the cause. They then did a couple of years worth of testing with Afton and a couple of other additive providers - and they were able to isolate the issue as being an excess of Calcium in the oil. Apparently, in those conditions, the Calcium acts as a catalyst, setting off the reaction seen!
Interestingly, other manufacturers were seeing issues with this on some engines - but not all - and some engines prone to the issue never had problems… in spite of obscene levels of Calcium in their oil! The API testing limits calcium, and encourages magnesium as an alternative. It does not take into account the effects of Ester base stocks, nor Molybdenum.
AMSOILs Signature Series SN oil - went through the API sequence testing with a 0 instance - the only oil tested at the time to score a 0… (The limit is like 6, based on my failing memory.) That is because both Molybdenum, and Ester base stocks act as relatively extreme quenching agents for LSPI. Something around 200-250 ppm of the proper Molybdenum will almost eliminate the possibility - effective dosing for many of these higher end oils has been around 600 ppm of the finest Moly available for some time (HPL, Red Line, Driven, etc.) Ester base is typically found in oils where PAO is used, and is also an effective quenching agent. Most high level oils use 7-15% Ester in the base stock blend, and it also acts as an effective suppressant to the reaction starting.
At the time, again, if memory serves - Signature Series 5W-30 was about 550-570 ppm Moly, around 12% Ester, and sported almost 3000 ppm Calcium…
In typical API fashion - rather than let the test performance speak for itself - they changed the additive windows - and required everyone to reformulate with more expensive additive packages using less calcium based detergent, and more magnesium based detergent which is about 4X as expensive, and was abandoned by Mobil in the late 90s as being less effective than some overbased Calcium alternatives…
So…
What does any of that have to do with a 5W-40 Euro spec oil? Nothing! Not a single bit of that is applicable or helpful for a 3.0L European diesel! Nor does it affect a BMW or Mercedes 3.0L GTDI - as they never had LSPI issues in the first place - they were properly engineered and tested around the existing oils - not rushed to production half baked!
The engines designed to use A3/B4 oils simply don’t require API SP.
The reason for that specification being made in your 2022 Ram owners manual? The ONLY SP formulated A3/B4 Euro Oils in the NorthAmerican market are Pennzoil, Quaker State, and Mopar, all Shell products - nobody else saw a need to re-invent the wheel, and make massive changes to fix the problem where a problem doesn’t exist.
In effect, it is a way of forcing you to use an oil made by their oil partner, and as they offer it in 3 flavors, it’s not technically 1 specific oil, so they don’t have to provide it for you, you have to pay for it! (That’s a Shell game - pun intended!)
The proof of that requirement is in the pudding (UOAs). The factory shipped oil in the 2022s will never meet SP requirements at 2700 ppm of Calcium…
www.ram1500diesel.com
