Well, when you mainatain viscosity, friction is reduced. When foaming begins, theres a higher rate of friction being generated, because vescosity is lost. I beleive he did, but I don't recall the results. I t must have been positive because I would have not taken the risk with my machines. I will contact him and get you a better answer.

 

THanks. I wonder if this pertains too the whole Castrol lineup? I run Castrol semi-synthetic 10-30 lately.