Best proven oil for subaru STI?

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So yesterday I ordered my 2015 wrx sti... it should be here first thing March. I plan on keeping it stock and being fastidious with maintenance. I want to aim for 4000 mile oil changes, it will be daily driven.

What has been proven to be the best oil for these motors? Redline? M1 0w40? Rotella? Motul?...
 
I believe your owner's manual requires 5w-30.

There are some UOAs around here with Pennzoil Ultra with decent results at 3,500-5,000 miles.

Rotella T6 5w-40 is the proven oil. Use your own discretion.
 
I would highly recommend http://www.pqiamerica.com/June 2014/ec5w30.htm everclear has advisory in a few states and has been on "consumer alert" status quiet a few times, it couldn't fathom a better outlaw oil for your car.

on a serious note: at 4k OCI I would think anything 5w30 synthetic blend to synthetic would be more then sufficient
 
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Aren't the turbo direct injection engines still fairly new to Subaru, or at least to the WRX's? With a new'ish engine it's difficult to say what oil is proven to work for it, but in the past thicker oils like GC, and Rotella T6 5w-40 have shown to be good in turbo Subarus.

If it were my vehicle, and if it didn't violate the warranty, I'd use something like Castrol 0w-40. It's actually a very thin 40, and I believe it would protect the engine and turbo just fine. If a 40 weight isn't allowed, then I'd go with something like GC, PP 5w-30, or M1 0w-30. Any one of them should offer ample protection for a 4k mile OCI.
 
Originally Posted By: sicko
Aren't the turbo direct injection engines still fairly new to Subaru, or at least to the WRX's? With a new'ish engine it's difficult to say what oil is proven to work for it, but in the past thicker oils like GC, and Rotella T6 5w-40 have shown to be good in turbo Subarus.

If it were my vehicle, and if it didn't violate the warranty, I'd use something like Castrol 0w-40. It's actually a very thin 40, and I believe it would protect the engine and turbo just fine. If a 40 weight isn't allowed, then I'd go with something like GC, PP 5w-30, or M1 0w-30. Any one of them should offer ample protection for a 4k mile OCI.


IIRC, the 2015 WRX has the new 2.0L, while the STI uses the legacy (not the car) 2.5L engine. Someone correct me if I'm wrong.
 
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Originally Posted By: thunderfog
Originally Posted By: sicko
Aren't the turbo direct injection engines still fairly new to Subaru, or at least to the WRX's? With a new'ish engine it's difficult to say what oil is proven to work for it, but in the past thicker oils like GC, and Rotella T6 5w-40 have shown to be good in turbo Subarus.

If it were my vehicle, and if it didn't violate the warranty, I'd use something like Castrol 0w-40. It's actually a very thin 40, and I believe it would protect the engine and turbo just fine. If a 40 weight isn't allowed, then I'd go with something like GC, PP 5w-30, or M1 0w-30. Any one of them should offer ample protection for a 4k mile OCI.


IIRC, the 2015 WRX has the new 2.0L, while the STI uses the legacy (not the car) 2.5L engine. Someone correct me if I'm wrong.



I misread the Subaru website, you're absolutely right the WRX has the direct injection engine, but the STI still uses the port injection engine.
 
Mobil1 will cause it to blow up
laugh.gif


I kid, I kid.
 
You threw out some non-recommended oil types/viscosities so I guess you're open to experimenting beyond the owner's manual recommdations. The best oil is one that is not Resource Conserving, IMO. Use any GF5 5W-30 if you want an oil that will likely shear to a 20 grade (stock or modded).

If you want a 5W-30 that will have a better chance of staying in grade try Mobil 1 ESP 5W-30 or Motul X-clean 5W-30. Keep the intervals at 5,000 miles or less on these oils due to the low TBN so 4k OCI's are good. Non-certified Motul 300V or Red Line are good as well. Don't use Motul Eco-nergy 5W-30 as it is thin at operating temp.

The factory oil is a thin (low 30 grade or 20 grade) Idemitsu with higher levels of moly and ZDDP than the dealer Idemitsu. I would probably do a uoa at 3k miles on the OCI after the factory fill as there have been a few 2015 STI bearing failures.

Enjoy the car!

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Dennis
 
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Amsoil CJ4 5w40, better than rotella T6. VERY good fuel dilution resistence and viscosity retention. Check it out.
 
Rotella T6 5w-40, every 3750 miles, and subaru OEM filters only. Its a great engine, but expect turbo issues at the 100-120k mark.
 
Originally Posted By: MrWideTires
So yesterday I ordered my 2015 wrx sti... it should be here first thing March. I plan on keeping it stock and being fastidious with maintenance. I want to aim for 4000 mile oil changes, it will be daily driven. What has been proven to be the best oil for these motors? Redline? M1 0w40? Rotella? Motul?...


Congrats on the STI order... I was really considering upgrading to the 15' STI myself but will hold on to my 13' WRX for a bit longer. Your 15' still has the prev gen 2.5L and its a great engine. I've been changing my oil every 5k since new and now that I just passed the 30k marker, going to increase intervals; did an oil analysis running Purol and TBN read 4.0 so going to look at 7,000 results later. Whatever oil you choose, 4k is low for today's synthetics, try 5k at least and get oil tested later when you have some miles on the car and see how it's doing. Enjoy the new ride, sweet handling car!
 
royal purple....attend a STI club rally, It the chosen oil by the majority!!
The others that didn't use royal purple seems to use Castrol.
 
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