Switching from GC to PU 5W-30 on a Subaru turbo?

[DrivinWest]

I've got a 2005 Saab 9-2X Aero (mechanically almost identical to a Subaru WRX) with an upgraded turbo, ECU, etc. I've done three oil changes with GC and done a UOA on two of them. GC has performed well in my Subaru motor. No surprises there.

I just went to pick up some more GC when I saw that Pep Boys has a deal on Pennzoil Ultra (5 quarts and a PureOne filter for $32.99). Based on the buzz, I picked up some PU 5W-30 (the weight which the oil cap calls for) instead of the GC.

Based on all I've read, Subaru engines tend to do well with thicker oils, and GC's cSt of 12.2 at 100degC and many GC UOAs seem to corroborate that. Pennzoil Ultra 5W-30 is a good bit thinner with a cSt of 10.3 at the same temp (http://www.pennzoil.com/documents/PENNZOILULTRAFullSyntheticMotorOil.pdf).

Any strong opinions about using the PU instead of the GC? The car is not tracked but it is driven in a spirited manner. I live in southeast Texas where summer days routinely top 100degF for months in a stretch but the winters are nice and mild.

With a lack of PU UOAs on the 2.0L Subaru turbo engines, I'm somewhat torn. I don't mind being the guinea pig, but if making the switch stands affront to the BITOG forum's conventional wisdom, I may rethink it.

 

[Johnny]

I say go for it. It sure won't hurt anything and may be a good lesson for all of us. Will you be doing a UOA on the Ultra?

 

[Alex38]

I'd also do it. Ultra is a good oil that meets the required specs.

 

[DrivinWest]

Originally Posted By: Johnny
I say go for it. It sure won't hurt anything and may be a good lesson for all of us. Will you be doing a UOA on the Ultra?


Absolutely gonna do a UOA. It will probably be a year before I need to change it, however! I'm about to store the car for 2 months and upon return I'll probably drive little more than 100 mile a week.

 

[Johnny]

My neighbor has a new Subaru Legacy that has a turbo and he is using the 5W-30 Ultra and is very happy with its performance. Very nice car and it does not make any strange noises nor does it have any consumption with the Ultra.

 

[DrivinWest]

Good deal. Thanks for the input. I may do a UOA mid-OCI to see if there is anything out of the ordinary, but I suspect it will work well.

 

[daman]

PU is a hard oil to bet should work in that application WELL,please post back the UOA.

 

[SubLGT]

Since this is a modified engine, I say use a 5W-40, or continue with the GC.

 

[shpankey]

Go for it. Pennzoil Platinum turns in awesome UOA's, so you know at the very least, it will be as good or better than that.