Acea a5/b5 vs a3/b4 cold crank pump ability

[shDK]

Hi all.

An earlyer tread mentioned something about cold crank pump ability. That made me wonder. Does anybody here know.

If we have 2 different 5w-30 oils; in this case two different European synpower . One is Acea a5/b5 the other one is a3/b4, I know the a5/b5 is lower on overall viscosity including the HTHS. But how much difference will there be on the cold crank pump ability?

Have a merry Christmas.

Søren

 

[d00df00d]

I don't think there'd be any way to tell...

 

[Clevy]

Depends on a lot of things. Viscosity index,hths,formulation etc.

Pick 2 oils to compare and it should be easier to dissect them.

 

[chrisri]

A5/B5 oil would probably have lower kinematic viscosity then A3 oil in same grade, but since both are 30 grade difference is probably small.

 

[Doog]

I doubt unless you were in a test laboratory that you could tell the difference.

 

[Shannow]

Given that it's cold temperature pumpability, regardless of what the KV100 and HTHS are, they have exactly the same limits on SAE J300 with respect to the extreme cold pumpability.

If you are needing the extreme cold end performance, the A5 is probably going to have an edge, albeit very very small, as the 5W covers the performance requirements.

Any reasonable sort of starting temperature, and the positive displacement pump will be pumping.