Buit engine 2012 Subaru STI (2.5L boxer engine, turbo)

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Hello,

I recently purchased a 2012 STI with a built 2.5L and big turbo gt35. The car runs a very conservative tune tho and has stock heads. I live in eastern Canada but i will be storing the car at the end of October so no winter driving, and the car will see some spirited driving but not abuse ( a few WOT runs every drive but not constantly). i do plan on changing the oil every 2500 miles since it is not a daily driver.

I am trying to contact the builders but no feedback yet. The previous owner says he was running 5w40 but switched to 5w20 because it looked better at oil change time.

To me it seems like 5w20 would be way too light for a built engine with forged pistons...

If you guys recommend 5w40, should i go the Shell rotella t6 ever since the new formulation? I have also been reading about the T6 5W30 Multi vehicle, should that be a good choice also? but then again maybe a 30 weight is on the light side.

Any feedback is appreciated since ive been reading alot and seem to be chasing my tail. Thank you

David
 
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I'd say go with a 40 weight maybe a euro oil. Castrol 0w40 is easily available at Canadian tire and when on sale it's around $30.
 
An A3/B4 should be a reasonable choice, and the Shell Rotella T6 Multi-Vehicle 5w-30 would be appropriate, too, given that it's got higher HTHS than the ordinary ILSAC 30 grades out there.
 
Without knowing your specifics, any 40 grade will likely work and there should be no problems extending that interval a bit IMO. In my Forester XT, which only has a Cobb Stage I OTS reflash, I ran Euro 30 grades and 40 grades in the past and currently running a blend of 10W-40 with some 10W-30 to 5k miles. Rotella 5W-40/5W-30 or any Euro 40 grade will last at least to 5k miles or more.

5W-20 or a GF5 Resource Conserving 5W-30 is too thin. I switched to 10W-40 because it seems to burn less than 0W-40, but anything is better than 5W-20! There's very little difference in the metallic additive levels in the new and old RT6 5W-40 so that's fine as well. As Garak mentioned, Rotella MV 5W-30 has a higher High Temp High Shear which will make your bearings happier than a standard 5W-30.
 
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