Vehicle: 2005 Subaru Impreza WRX STi
Engine: 2.5L Turbo
Engine Mods: COBB Stage 1 (ECU reflash providing an additional 25 HP)
Fuel Type: Gasoline (Unleaded); 92 or 93 octane (mostly 92 octane)
Air Filter: OEM Paper (original from factory)
Oil Filter: OEM (Part #15208AA080)
Oil Capacity: 4.8 Quarts
Additives Used: None
Oil in Use: 10/24/06 - 08/03/07 (283 Days)
Driving Conditions: I would consider myself a semi-aggressive driver in general. This OCI included quite a bit of time spent parked in the garage while I was looking for work over the late fall and winter months. As a result, the car would sometimes sit for a week undriven and then only driven for a few miles. I tried to avoid these short-trips whenever possible, but sometimes they were inevitable. Starting at the beginning of March, the car was pressed into commuting duty once again and my normal commute consists of surface streets for about 2 miles and then highway driving for 15 miles at speeds ranging from 50 MPH - 80 MPH.
Blackstone's Comments:
Both silicon and potassium improved nicely in this sample. Wear was virtually unchanged in this sample from the last. The oil was in good shape physically, containing no moisture, fuel, or coolant. The air and oil filters are working well too. The TBN read 2.6 showing that some active additive was remaining. 1.0 is considered too low for extended use. At 27,802 miles we have no problems to report. It would've been nice to see wear drop on the shorter oil change, but nothing is high enough to show any sort of problem.
My Comments:
I was happy to see the potassium level decrease as I was (still am) worried about the possibility that the engine has a small internal coolant leak. I am due for a 30,000 mile service in approx. 2,000 miles or so at which time the coolant is due to be replaced and I believe Subaru will add some coolant "tabs" at this time as well as part of this service. I will probably mention the potential coolant leak, but I think I'll continue to play it by ear and see how my next UOA looks. There was no additional make-up oil added during this interval. The oil was replaced with Pennzoil Platinum 5W-30 which I bought for $0.99/quart at Checker's back a few months ago. I still have a pretty large stash of GC (both "green" and "gold"), so I'm not sure what I'll use at my next oil change. Just for the record, the GC used in this latest UOA was of the "green" variety.
Any and all comments are welcome.
Engine: 2.5L Turbo
Engine Mods: COBB Stage 1 (ECU reflash providing an additional 25 HP)
Fuel Type: Gasoline (Unleaded); 92 or 93 octane (mostly 92 octane)
Air Filter: OEM Paper (original from factory)
Oil Filter: OEM (Part #15208AA080)
Oil Capacity: 4.8 Quarts
Additives Used: None
Oil in Use: 10/24/06 - 08/03/07 (283 Days)
Driving Conditions: I would consider myself a semi-aggressive driver in general. This OCI included quite a bit of time spent parked in the garage while I was looking for work over the late fall and winter months. As a result, the car would sometimes sit for a week undriven and then only driven for a few miles. I tried to avoid these short-trips whenever possible, but sometimes they were inevitable. Starting at the beginning of March, the car was pressed into commuting duty once again and my normal commute consists of surface streets for about 2 miles and then highway driving for 15 miles at speeds ranging from 50 MPH - 80 MPH.
Blackstone's Comments:
Both silicon and potassium improved nicely in this sample. Wear was virtually unchanged in this sample from the last. The oil was in good shape physically, containing no moisture, fuel, or coolant. The air and oil filters are working well too. The TBN read 2.6 showing that some active additive was remaining. 1.0 is considered too low for extended use. At 27,802 miles we have no problems to report. It would've been nice to see wear drop on the shorter oil change, but nothing is high enough to show any sort of problem.
My Comments:
I was happy to see the potassium level decrease as I was (still am) worried about the possibility that the engine has a small internal coolant leak. I am due for a 30,000 mile service in approx. 2,000 miles or so at which time the coolant is due to be replaced and I believe Subaru will add some coolant "tabs" at this time as well as part of this service. I will probably mention the potential coolant leak, but I think I'll continue to play it by ear and see how my next UOA looks. There was no additional make-up oil added during this interval. The oil was replaced with Pennzoil Platinum 5W-30 which I bought for $0.99/quart at Checker's back a few months ago. I still have a pretty large stash of GC (both "green" and "gold"), so I'm not sure what I'll use at my next oil change. Just for the record, the GC used in this latest UOA was of the "green" variety.
Any and all comments are welcome.
