'Blends' - same ccs value was regular 'W' oils?

[addyguy]

...confusing title....let me explain my question, something I'm very curious about!

If you blend two oils together, they can 'become' a different viscosity...I know not literally, but close. Example, if you blend 5W-20 equally with a 15w40, you get something akin to a '10W-30'.

What I'm wondering is will that '10W-30 blend' actually meet the ccs values for a 10w30 oil? A 10w30 oil, by definition, has a ccs value of less that 7000cp @-25C. If I blend a 5W-20 with a 15w40 and 'create' a 10w30, would that blend have a ccs value in that range?

'5W' oils are ccs tested at -30C; '15W' oils are ccs tested at -20C, do the two even out in the middle?

 

[dparm]

Interesting question. I doubt it's linear at very low temperatures, unlike high temperatures. I'd guess exponential/logarithmic.

 

[Quattro Pete]

Without an actual CCS test performed, there is no telling. However, I'd expect it'd be somewhere near.

 

[KCJeep]

In my experience no. You can blend and modify to your hearts content, and the blend you mentioned would be similar to a 10w30 hot but it would most likely have inferior cold start characteristics compared to an over the counter 10w30.

It seems to be quite easy to modify full temp viscosity but things seem to go south the colder it gets as far as getting a predictable and satisfying result. Just the real life observation experiences of a self confessed addicted blender.

 

[jrustles]

Originally Posted By: addyguy
...confusing title....let me explain my question, something I'm very curious about!

If you blend two oils together, they can 'become' a different viscosity...I know not literally, but close. Example, if you blend 5W-20 equally with a 15w40, you get something akin to a '10W-30'.

What I'm wondering is will that '10W-30 blend' actually meet the ccs values for a 10w30 oil? A 10w30 oil, by definition, has a ccs value of less that 7000cp @-25C. If I blend a 5W-20 with a 15w40 and 'create' a 10w30, would that blend have a ccs value in that range?

'5W' oils are ccs tested at -30C; '15W' oils are ccs tested at -20C, do the two even out in the middle?


Interesting thing to consider.
Wouldn't it depend on the chemistry of the oils being mixed?

For example, does one or the other rely on higher vis base oil and PPDs or low vis base oil with VIIs. Diluting PPDs would certainly degrade CCS beyond an average one might expect from mixing, even moreso if blending lower group oils that are prone to crystallization.