I'll still say that lower temporary shear to HTHS is better.
I've touched on it before (and been poopoohed a couple of times for sure) Reason being that if you take the premise that (say) 3 HTHS is needed for protection, then it's silly to be pumping 12cst oil around the galleries, which are all running in the low shear kinematic range, you are increasing the (small) power wastage, and importantly, changing the pressure distribution around the engine...furthest bearing from the pump will have a lower supply pressure than the closest, exaccerbated by the artificially high KV100 figure...
It's part of the reason why I consider oils like amsoil's SAE30 with 10W30 performance sans VII in a different league to regular multigrades.
edit: the above was the reasoning that in the recent Castrol Edge Deal in Oz, 5W40 or 5W30 A3/B4 for $27 for 5L, I chose the 5W30 for my Nissan.
I've touched on it before (and been poopoohed a couple of times for sure) Reason being that if you take the premise that (say) 3 HTHS is needed for protection, then it's silly to be pumping 12cst oil around the galleries, which are all running in the low shear kinematic range, you are increasing the (small) power wastage, and importantly, changing the pressure distribution around the engine...furthest bearing from the pump will have a lower supply pressure than the closest, exaccerbated by the artificially high KV100 figure...
It's part of the reason why I consider oils like amsoil's SAE30 with 10W30 performance sans VII in a different league to regular multigrades.
edit: the above was the reasoning that in the recent Castrol Edge Deal in Oz, 5W40 or 5W30 A3/B4 for $27 for 5L, I chose the 5W30 for my Nissan.
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