Rotella T Synthetic in a 2.5l Turbo STi?

[LoubaruNW]

I'm was planning on switching my slightly modified 07 Subaru WRX STi to Rotella synthetic. I just wanted to hear everyone's opinions first. Incase you don't know, these cars come with a 2.5l turbo horizontal motor, they make ~300hp stock.

I bought the car new and have been running Castrol dino up until now (10k miles). I'm planning on changing the oil to synthetic before I do a track day in a few week. The car is boosting ~18psi and making around 350-380hp to the crank, so its nothing to crazy for one of these cars. Oh, and I have no cats.

What do you guys think about Rotella for my set up? If you don't like Rotella, what other oils would you recommend?

 

[JAG]

I think it's a good choice in either the old API CI-4+/SL spec or the new CJ-4/SM spec. The new version meeting API CJ-4/SM spec recently showed up at stores.

 

[marco246]

I consider Shell Rotella T Synthetic 5W-40 to be the closest thing to a universal motor oil on the market. It will work well in virtually any application. Admittedly it will be better in some applications than in others. But the price is right, the quality high, and the availability good.

I have it three applications as of now: '71 Alfa Romeo 1750, '87 Ferrari 328, and '04 John Deere 4610 (Yanmar diesel). I am sure it will work well in your Subie.

Cheers!
Mark

 

[Saab9-3]

Great oil, if you want other options, I know the Subie guys up here love MOTUL for there high power sti's. But its quite pricey.

 

[Volvohead]

RTS is a great budget oil. Plenty robust for a mildly modded WRX.

Other great picks are RL, Delvac 1, M1 0w-40 and GC. Between RL and Motul 300V (both are POEs), I think RL is the better value.

I might not run the RTS or M1 0w-40 as long as the others, though. The 0w-40 shears down too quickly for my tastes.

All will give you plenty of protection with mods. The RL might do it a little thinner than the others, which can help performance getting that big blower up faster. Definitely like the RL if you're tracking, too. Then I'd run it in a 5 or 10w-30. It can handle it.

 

[[RT] ProjUltraZ]

the 06 and up WRX STis are gorgeous and fast, i drove one and loved it, what is it spec'd for? 5W-30?

 

[LoubaruNW]

Thanks for the quick replies guys! Great info.

ProjUltraZ, yes the 2.5l turbo subies are pretty fast, fast enough for me at least (for now...)! The car is spec'd out for 5W-30 and the Rotella Sythn is 5w-40. I doubt this will be a problem though, don't a lot of car companies spec 5w-30 to get better gas mileage?

I would run GC, but I can't find it anywhere near me. I may look into running AMSoil or Motul in the future, but I can't help but feeling like I'm waisting money running $7-9 a qt oil. I guess with a relatively expensive car I probably should just suck it up and bite the bullet...

 

[Volvohead]

Originally Posted By: LoubaruNW
. . . I may look into running AMSoil or Motul in the future, but I can't help but feeling like I'm waisting money running $7-9 a qt oil. I guess with a relatively expensive car I probably should just suck it up and bite the bullet...


Motul is a lot more than $9 a quart. Amsoil and RL are significantly cheaper than 300V.

Running a high end synthetic is not wasting money in a HP turbo. These are hard on oil.

All I run in our R is RL 10w-30. GC is a near 40 and would be my alternate choice. Any thicker and you start dulling turbo response.

Spool up speed is a big deal with a turbo. You don't want to go too thick or it will bog down.

 

[Saab9-3]

Dont forget, that MOTUL makes other oils than the 300v. Their Xcess 8100 5w40 would be a cheaper option which are along the same price as amsoil or RL.

Dont get me wrong Amsoil is a great product, but I dont believe you can put it in the same category as MOTUL 300v, maybe there new dominator oil would be in the same category if not better.

 

[bluesubie]

Volohead lists some great choices, IMO.

And about M1 0W40, there is a uoa on nasioc from a naturally aspirated 2.5RS that ran it for 4,300 miles and it sheared to a 30 grade. I think that can be expected. Actually, a stock Forester XT in Florida runs M1 TDT 5W40 (Delvac) and even that has sheared to a 30 grade on several runs.

5W30 isn't necessarily spec'd. The manual probably says that 5W30 is preferred for fuel economy, and that a thicker viscosity is required in high temps and in severe conditions. SAE 30, 40, 10W40 and more are all listed in the manual.

What mods are you running and what EM? A good tune is probably as important, or more important, than oil choice.

-Dennis

 

[Volvohead]

Originally Posted By: Saab9-3
Dont forget, that MOTUL makes other oils than the 300v. Their Xcess 8100 5w40 would be a cheaper option which are along the same price as amsoil or RL.


Might be. But the 8100 is not in the same league as 300V or RL.

Why pay for steak and get a very nice hamburger?

 

[Volvohead]

Originally Posted By: bluesubie
A good tune is probably as important, or more important, than oil choice.


With these small displacement, high HP/L blower engines, you need to more carefully match the oil to the level of tuning.

Once you start getting substantially above the design HP, you start to stress the stock internals towards their durability limits. Asking 335 or 350 (or more) hp out of a 2.5L 300 hp street block is pushing the envelope, you're risking warranty coverage, and a more robust or heavier oil may be needed. Throw in tracking, and you've got he-11's kitchen going on under the hood.

So I look at it the other way: the oil is more important than the tune. A strong oil can handle a ho-hum tune. But a weaker oil in a heavily tuned engine is playing with danger.

 

[Detroit_Doc]

Originally Posted By: Volvohead
Asking 335 or 350 (or more) hp out of a 2.5L 300 hp street block is pushing the envelope


335 or 350 at the crank is nothing for these motors. Tell that to the guys putting down 600 to the wheels.

My PE1818 turbo'd 2.0 liter WRX (~400 HP @ crank) did just fine on M1 5w30. Your turbo is spinning at well over 100,000 RPM. I would not stray too far from the recommended viscosity unless you want to replace your turbo's center section.

 

[LoubaruNW]

My mods are:

Invidia V2 DP (bellmouth)
Maddad Whisper CBE (full 3 inch, no tapers)
APS 65MM CAI
3 port boost solenoid

and I have a dual catch can set up that I'm still working on modifying and figuring out where I want to mount them, I should have these installed before I hit the track.

The tune is done by a very well known tuner via open source (Rom Raider). He has tuned 100s (if not 1,000s) of Subarus and owns 5 himself, including a ~450 (crank) hp 07 STi. The tune is pretty mild and is only boosting ~18 psi on 92 oct. I have been logging the tune and am not worried about it.

 

[LoubaruNW]

And as Doc stated, the power level I'm running is nothing for these cars.

I'll probably end up using Rotella and sending it in for a UOA. If it comes out good, I'll keep using it; if not, I'll look into Motul or another good synth.

 

[bluesubie]

Originally Posted By: Volvohead
So I look at it the other way: the oil is more important than the tune. A strong oil can handle a ho-hum tune. But a weaker oil in a heavily tuned engine is playing with danger.

Good point.

I was thinking of all of the spun bearings on Mobil1 5W30. A lot of people have had luck with it (like DetroitDoc apparently), but there was a slew of spun bearings for a while on nasioc. Unfortunately, none of those folks did any uoa's so it's hard to just blame the oil (although a lot of people do). Most were modified 2.0L's.

BTW, I had my OEM turbo replaced under warranty at 65k with a new one due to excessive oil getting past the seals. I ran GC with normal uoa's so I don't know if it was a viscosity issue or not.

It was the first that my dealer had seen on a stock engine.

Lou - Sounds like you're on the right track!

-Dennis

 

[thunderchild]

I just bought a 2009 2.5i Outback. I have alot of Rotella 5w-40 in my stash. It does say 5w-30 recommended, but I drive 100+ miles a day on the highway 95%. I think the Rotella would be great for my use. Good protection for all the driving I do especially in the summer month's. It does get hot here in MD. What is the concensous of the panel? I like this topic.

 

[bluesubie]

The n/a Subaru's are a bit easier on oil than the turbo's and do well with most any brand and viscosity! Although there's probably nothing wrong with you running RTS, IMO. I think I would try 7,500 mile OCI's. Supported by uoa, of course.

-Dennis

 

[jennings]

I'm on my second change with RTS 5w40 in my 2005 Legacy GT. I don't run my car hard, but I am happy that this oil stays around a lot better than the 5w30. With 5w30 at least a quart used between 5000 mile changes. Rotella consumption about half that.
And it sure gets nasty black over 5K miles.