Amsoil 10w-30

[SonofJoe]

Jetronic,
If an oil contains some PPD, then the CCS and MRV tend to move it tandem. If you drop the CCS, then you automatically drop the MRV. So it's nigh on impossible to pass the CCS and fail the MRV in the way you suggest.
I can't remember exactly what happened as it was several years ago. I do sort of recall however that the customer (no names) wanted something that was basically impossible in that they wanted to tag GF-4 fuel economy onto an SL oil which also needed to meet A3/B3 (ie needed to meet 3.5 min HTHS). I had carte blanche from the customer to do whatever was needed to be done to get the pass so I probably did something dramatic and halved the usual CCS. What I forgot was that in rough terms, CCS doubles for every 5C you drop the test temperature so my oil just dropped into being an on-grade 5W30. Hence the grief from upstairs!
The irony was after all this got aired and after a lot of shouting, I got a legit pass...which the customer then completely ignored and went with what he wanted in the first place. Such is life...

 

[Jetronic]

but if you look at the CCS, the limit gets lower and lower as the grade drops, while the MRV stays the same (at lower temperatures)

13,000 for 25w
9500 for 20w
7000 for 15w
7000 for 10w
6600 for 5w
6200 for 0w

pumping viscotity all 60,000 cP.

so if they truly move in tandem, the ccs gets harder and harder to meet, esp for high HTHS oils.

 

[SonofJoe]

The Low Temperature Pumping Viscosity (or Mini Rotary Viscometer; MRV) limit of 60,000 cP max is temperature referenced just like the CCS. The MRV is always run at a temperature 5C lower than the CCS; not one single temperature. This way the two viscosities always move in sync.

 

[Jetronic]

Yes, but the relationship between the two changes, as the mrv is always 60,000 cP (at whatever the temperature of the grade is) vs the MRV at 0w being under half of what the limit for a 25w is. Hence the chance of meeting the MRV is getting harder at lower ratings, esp for high HTHS oils

And as the MRV is a dynamic rating, you have to add density into the equation, making the task at hand even harder as it gets colder.

Disregarding density, the ccs/mrv ratio for a 25w is just over 4 to 1, but for a 0w nearly 10 to 1.

Anyway, not an issue now, but if you only meet 1 of the 2 for a 5W, it's still a 10W. and if you only just got under 60000 cP, the MRV might have been above 6600 depending on what you started with.

 

[BrocLuno]

Originally Posted By: Jetronic
you could use an ester oil to dissolve the additives, if you want 100% synthetic.


Do they order their add-pak from Lubrizol (or whoever) that way ... I'll bet breakfast they don't ...

 

[Jetronic]

Originally Posted By: BrocLuno
Originally Posted By: Jetronic
you could use an ester oil to dissolve the additives, if you want 100% synthetic.


Do they order their add-pak from Lubrizol (or whoever) that way ... I'll bet breakfast they don't ...


Me too, but that doesn't mean it can't be done....