Help me understand cold behavior between two 5-40s

[MinamiKotaro]

Mag1 Euro 5-40
Viscosity @ 40°C cSt: 76.77
Viscosity @ 100°C cSt: 12.95
Pumping Viscosity at (°C), cP: 28,400 (-35)
High Temperature / High Shear Vis at 150°C, cP: 3.7
Viscosity Index: 170

Mag1 All-Fleet 5-40
Viscosity @ 40°C cSt: 87.75
Viscosity @ 100°C cSt: 14.76
Pumping Viscosity at (°C), cP: 24,113 (-35)
High Temperature / High Shear Vis at 150°C, cP: 3.5
Viscosity Index: 177

The Euro has lower viscosity at 40C and 100C but ends up 4300 cP higher at -35. Does this indicate that the All-Fleet, despite being somewhat more viscous at 40C and 100C, would actually be a thinner oil at startup under all conditions, or only at extreme cold?

 

[Brybo86]

I would go with the euro spec.... how often does it get to -35 in tennessee?

 

[MinamiKotaro]

I'm using them both in different applications. I was wondering if the pumping viscosity test is only applicable for extreme cold or if a better result there can be taken to imply better cold start performance even at "normal" temperatures.

 

[dave1251]

There both close enough in anything but the arctic your engines could not tell you the difference.

 

[chubbs1]

The Mag 1 all fleet has a higher VI and better extreme cold flow characteristics. How much VII and PPD's to make the Allfleet meet the viscometrics vs if it is a better base make up is the million dollar question. I would use the "flip the coin" method.

 

[MinamiKotaro]

Ok. So the Euro, being an a3/b4 oil designed for long drains, has a thicker base stock as insurance against viscosity loss. The All-Fleet has a thinner base stock with more VI improvers. They each take a bit different route to get to 5-40.