Originally Posted By: CATERHAM
I have given you the data before when you high-jacked that PP 0W-20 vs TGMO thread a while back with a similar M1 praising rant, which you have conveniently chosen to forget. Anyway here it is again.
M1 has a CCS @-35C of 4110cP. Source PQIA.
Sustina's CCS @-35C is 3550cP from the same source you got their MRV.
I would like to see PQIA's data for CCS for Sustina (though I doubt we are going to). I know it is a standardized test but still. Also, CCS and MRV are measured using two very different methods, which may help explain the difference.
The reason I am taking issue with this (and I know, you'll say to fit my agenda but there is more than that):
Quaker State 0w-20:
http://www.pqiamerica.com/June 2014/quakerstate.htm
CCS: 5,958cP according to the PQIA.
According to the SOPUS data sheet:
http://www.epc.shell.com/Docs/GPCDOC_X_cbe_24855_key_140003587108_201007020117.pdf
It should be 4,840cP (which aligns reasonably well with the other values from the PQIA test)
or: 6,070cP (this data doesn't align as well
) if we use this PDS:
http://www.epc.shell.com/Docs/GPCDOC_GTDS_Quaker_State_Ultimate_Durability_0W-20_Full_Synthetic_Motor_Oil_%28SN_GF-5_2013%29_%28en%29_TDS.pdf
And even with the above data, it gets more curious
The older QS 0w-20 with the 4,840cP CCS has an MRV of 17,500cP
The newer QS 0w-20 with the 6,070cP CCS has an MRV of 15,000cP
Which easily explains the difference in CCS between M1 0w-20 and Sustina on the CCS test if the data IS accurate
Originally Posted By: CATERHAM
Despite M1 having a 4% lower MRV it's CCS viscosity is already 14% higher at -35C and that viscosity trend continues to 0C where Sustina is 50% lighter.
No, this just means it has a higher CCS @ -35C than it has MRV at -35C. They are two different testing methods.
Originally Posted By: CATERHAM
So much for relying the MRV spec' to predict viscosities at warmer temp's.
Not quite. If we use MRV, the difference remains. If we use CCS, the difference remains. We just get different results for the two different testing methodologies.
A good read on this (which explores the limits of CCS and MRV and actually gives some exceptional examples, like a 4.0L engine that the oil will not pump in above 30,000cP MRV, despite the newer limit, established in 1995, of 60,000cP, which applied to newer engines):
here:
CCS and MRV differences
Originally Posted By: CATERHAM
MRV and CCS spec's aren't very relevant at temp's warmer than -30C for 0W-XX oils. You agree that using a viscosity calculator KV40/KV100 spec's will predict viscosity down to at least 0C. The ultra high VI 0W-20s like TGMO, MGMO and SynGard are 40% or more lighter at that temperature and that head start advantage as temp's decline further should hold up until at least -30C if the Sustina spec's are anything to go by.
I would say they begin to lose relevance around -15C, which, between that point, and 0C, there is a crossover between that testing methodology and calculated visc from a calc.
Once we are below 0C, the thickening characteristics of the lubricants will vary greatly depending on the base oil blend and how it is additized. A quick glance at some of the XOM Chemical PDS's for their excellent PAO base oils demonstrates part of that. But we've been over that before, it is amazing stuff.
I would love to have the equipment to plot each of those products in 5C increments down from 40C to the MRV temp to see how the curves look. I'm sure you'd be interested in that data as well.
Originally Posted By: CATERHAM
Since this thread is about RP 0W-20 it is 12% lighter than M1 at 0C and it's MRV is 20,000cP, typical for a 0W-20. The 34,000cP figure is for their 0W-40, they have obviously been transposed. RP's lower 0C viscosity advantage vs M1 should be good to at least -10C and perhaps lower, it is really hard to predict short of actually trying both oils in a car with an OP gauge.
If the 0w-40 and 0w-20 have been transposed, then so have the 5w-20 and 5w-40. Look at those values too. Also, if you believe this is in error, Royal Purple should be contacted. As it stands, those are the values on the sheet, so they are what we have to go by. Based on those numbers, the cold temperature performance for the 0w-20 is comparatively awful.
And that 12% is insignificant; a few cSt. The big difference is below 0C if the PDS is accurate, which I have no reason to believe it isn't at this point, given the other values on it.
Originally Posted By: CATERHAM
The other thing to remember when choosing any 0W-20 regardless of what it's MRV/CCS spec's are, if the start-up temp' are below -30C you're starting the engine well within the cold cranking and borderline pumping limits of the oil. Once the engine fires up what's important next is how quickly the oil warms up and thins out. Since the high VI oils are so much lighter as you approach 0C the oil pump will come out of bypass mode sooner on idle and you'll be able to use progressively more rev's out of bypass as the oil continues to warn up and thin out.
But once the oil begins warming, the viscosity drop is dramatic regardless. I'm not concerned about how quickly it goes from 400cP to 100cP for example, I'm more concerned with how quickly it goes from my start-up temp, which, if it is -35C, could be 10's of thousands of cP to that 400cP number. That is going to happen a lot quicker with an oil with superior CCS/MRV specs; that curve is less steep. An excellent example of that would be Sustina vs the QS product I mentioned earlier which is literally twice as heavy. Based on MRV, the Sustina is going to be half as thick right up to -15C (roughly). If we use CCS, there is a similar difference between the Sustina and the newer QS 0w-20, with the CCS being almost double that of the Sustina product. It will hold that advantage the entire way to operating temperature (getting progressively less significant of course but still). If we choose two random data points closer to 0C, the Sustina product could be 400cP whilst the QS product is still 800cP.
And of course the other factor is how well the oils that are reliant on base oil VI hold up over time vs oils that are additized to perform a certain way. That's a curious situation that I think we also need to ponder. How well things like PPD's age and how it affects this data over an OCI.
