Oil Recommendation E85 Subaru STI

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Hey folks - I've done some searching and have found very little info on here about Subaru's in general
I'll get the questionnaire first


1. What kind of vehicle you have
2004 Subaru STI (USDM) EJ257 engine has been rebuilt using Forged Pistons and Rods. The car is running a slightly larger than stock turbo ( Blouch 16G XTR Blouch 16G XTR). I'm also running E85 Fuel on a daily basis. The car also runs an aftermarket oil pan with an additional 1 quart capacity.

2. What your owner's manual says -- not just viscosity, but certifications (look for acronyms like API SM, ILSAC GF-4, etc.) and change intervals as well
I'm so far from original, I don't think this is super relevant, but 5W30 ILSAC GF-3
Interval is ~4000 miles per Subaru service bulletin years ago

3. Where you live
Silicon Valley

4. How you drive (easy? hard? fast? slow?)
The car is now having a 50-mile roundtrip commute in heavy bay area traffic. When I have room to run the car gets driven hard seeing canyon runs and autocross.

5. What your daily drive is like (short trips? long trips? city? highway?)
see above

6. Whether your car has any known problems

No


Here's the situation, for years my Subaru has been mostly a weekend/nights car. In the past, I've always used Torco, Redline or Amsoil for my motor oil. Figured they were overkill, but here we are. Subaru STI's have a short oil change cycle of 4000 miles, this isn't due to old thinking, that is the actual factory recommendation.
I've recently taken a new job that's about 25 miles away and have to use this car to commute (
frown.gif
). Now that I'm putting 1000+ miles per month on the car I'm really not wanting to spend $14/quart on oil; so am considering some less expensive options.
My company has a deal with Castrol (no not German) where I can buy it CHEAP so I'm leaning towards Edge.
I have nothing technical to back this up, but Mobil 1 is universally reviled in the Subaru community. Something about the formulation supposedly eats rod/main bearings.

I've built a spreadsheet trying to compare oils and that hasn't gone well.
Spreadsheet

When I asked the engine builder about what to use, his answer was a rather ambiguous "use Motul, Torco, Redline... they are all fine "
I'd love a recommendation from the pros
 
Those engines DO NOT LIKE 5W30. Subaru states in the owners manual there are certain conditions that warrants a thicker oil.
I owned an 07' WRX which I bought new and use to go on the NASIOC website. I would use any 0W40 that meets the Porsche A40 spec in your STi
such as Castrol Edge 0W40. It is a true synthetic PAO oil made in Europe and available cheap in 5 quart jugs at Walmart.
There is no need to use Rotella 5W40 which is a popular choice among turbo Subaru owners. It's good, but not as good as something meeting the Porsche spec.
 
Castrol, Mobil, Pennzoil 0W-40 if you want to try a Euro PCMO.

Delvac, Delo, Rotella 5W-40 if you want to try an HDEO.

Either would be fine choices.
 
Originally Posted By: rooflessVW
Castrol, Mobil, Pennzoil 0W-40 if you want to try a Euro PCMO.

Delvac, Delo, Rotella 5W-40 if you want to try an HDEO.

Either would be fine choices.


ditto
 
Originally Posted By: rooflessVW
Castrol, Mobil, Pennzoil 0W-40 if you want to try a Euro PCMO.

Delvac, Delo, Rotella 5W-40 if you want to try an HDEO.

Either would be fine choices.
These oils, plus a really good tune for E85 and possibly another tune for premium in case you are too far away from any E85.
 
1. 2010 Forester 2.5
2.OM for 2010 Forester on (p 11-1 states: "5w30 is preferred" p 11-2 states that:If the vehicle is used in desert areas, in
areas with very high temperatures, or is
used for heavy-duty applications, use of
oil with the following grade and viscosities
is recommended.
API classification SM (or SL):
SAE viscosity No.: 30, 40, 10W-50,
20W-40, 20W-50."
I chose to go with what the OM states as the "preferred" choice. SAE 5w30 Perthaps if I lived in a hot desert like Palm Springs CA I would go with a 5w40.

I try to do OCI every 5K using 5w30 conventional TSC or travelers oil I have pushed the OCI to 7k a couple of times, but try to do my OCI right at 5k. Am over right now but it is too darn cold in my unheated garage so I will wait a month or 2 for temps to warm up. it is not going to harm it any and I have Zero desire to change oil while laying on my ice cold garage floor in 10 degree temps.
3. Lincoln NE
4.About 75% city 25% interstate driving in temp ranges from -17 to +100 temps rain, snow, ice, and dry. seldom drive on gravel roads and mostly on flat areas.. not many steep grades here in eastern NE.
6. No problems with my Forester.
 
Aren't the dexos oils supposed to have E85 usage in mind? Any synthetic dexos oil will probably work fine in your E85 Subaru
smile.gif


You may want to get a UOA done at the end of the OCI
 
Originally Posted By: fozzdesy2001
Originally Posted By: rooflessVW
Castrol, Mobil, Pennzoil 0W-40 if you want to try a Euro PCMO.

Delvac, Delo, Rotella 5W-40 if you want to try an HDEO.

Either would be fine choices.
These oils, plus a really good tune for E85 and possibly another tune for premium in case you are too far away from any E85.


For the record, I run a flex fuel kit and a custom tune from https://www.delicioustuning.com/
Same guy who tunes Ken Block's cars
 
Non turbo, 2.5 with 4EAT. It is the standard no frills 2010 forester, just the way I like it, but I would not complain if it had the heated seats during this current cold snap.
 
Ended up ordering the Castrol 5W40
Meets the Porsche A40 spec and is specified as meeting later Subaru EJ257 engine specs. Seems hard to go wrong.
The numbers are pretty impressive
https://msdspds.castrol.com/bpglis/Fusio...BPXE-AA5D4U.pdf

The 0W40 is interesting, that may be the way I go next time. I like that the 5W40 has a Subaru approval
 
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^^It meets A3/B4, BMW-LL01, A40 and has a HTHS of 3.7. nothing wrong with that for a turbo boxer. One thing to remember is that E85 is 'more likely' to contaminate your sump with fuel. However since you're doing 25mile trips on the highway, the oil temp will flash off any volatiles.

regrds
Jordan
 
Originally Posted By: Konstantine
Why not use the manufacturer recommended 30 grade? Are you using it on the track?

He's probably running at least 100hp over factory; I'd wager even more than that. With that you can expect higher bearing loads AND increased fuel contamination. He's also running E85 which isn't nice to oil.

He could run Redline or an A3/B4 5W-30, but those have a similar viscosity and HTHS to the Castrol 5W-40 he's already bought.
 
it's 95% street car.
Factory engine has cast pistons, a different turbo and doesn't run on E85.
 
Originally Posted By: bulwnkl
Best choice by far is Renewable Lubricants 5W40HD

What makes it "best" over something like Mobil Delvac 1?
 
If I had a dollar for every person recommending weak sauce islac 5W30 to a WRX owner with mods on bitog...

Glad you went with the 40 grade edge OP. Last oil slip up of the week went to someone recommending a thinner viscosity using two completely different engines as their reasons. This week goes to the poster hinting to use the same viscosity as their naturally aspirated non modded version of your engine. Pffft, turbo, E85 big deal!
 
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