Quote:
Originally Posted by bluesubie
Keep in mind that the history that we have on Subaru boxer oil choices, and the preference to run Rotella T6 5W-40, is in turbocharged Subaru's that have historically allowed 5W-40 and even 50 grades in severe conditions. You're talking about 2.5T's pumping out 265-305 hp and 244-290 lb ft of tq in stock trim. Post 2011, turbocharged Subaru's now all spec 5W-30 with xW-40 no longer being allowed except for replenishment (not that I agree with that for the reasons you already mentioned!).
Given that many GF5 5W-30's will shear to a 20 grade in a turbocharged Subaru (and possibly even a BRZ/FR-S), how much more bearing protection can one expect from an xW-30 anyway? 50 bucks says that n/a Subaru's will be back-specced to 0W-16 when the new GF6 spec comes out. 
-Dennis |
A good 0w30 won't shear to 20w, I am chosing 0w20, my only concern is HTHS and rod bearings. Time will tell what's the right choice.
Best data we have right now is the UOA of 0w20 Sustina showing no copper bearing wear. Hope the less expensive 0w20's perform as well.