Subaru 2.5 STi/Forester - GC or XD-3 good?

y_p_w · May 24, 2005

quote:

Originally posted by bluesubie:
The oil coolers and the water cooled turbo's definitely help! Yeah yeah, DCCD, 6 speed and Brembo's. Showoff!

Only if we had the Forester STi here!

As to not following the manual, I'm on the fence on that one. The manual specifies "recommended viscosities" but not "required viscosities". Don't remember what it says about starburst oils. IMO, if it comes down to engine failure, your relationship with a dealer might be helful. I go to mine for services that I don't perform myself (spark plugs, brakes, etc.).

I remember using 0w30 oil in my '95 Integra GS-R after the warranty period was over. I called Acura technical support and got some vague reccommendation that only the oil weight listed in the manual were appropriate. Of course it would be possible to take a 0w30 oil and relabel it as 5w30, so what's the point? The SAE viscosity scales may be outdated to a point.

ringmaster · Jul 11, 2005

quote:

Originally posted by olympic:
GC and XD3 are excellent choices and would work fine in your car. Personally I would start with the 0w30 XD3 since it's nearly a 40wt as is.

There is one big word of caution here though, neither oil carries the proper API ratings for your car, so if you blow the engine or turbo, Subaru could use that against you to deny warranty. Auto manufacturers are getting pretty sticky about these things lately so it's definitely something to keep in mind.

The XD-3 0W30 is quite heavy isn't it. I wonder if it would rob some power compared to true automotive oils?
I hadn't considered this API point. Not that I am too worried about the warranty (I have done lots of power mods!) but I might be better of going with the Motul 8100 0W40 for a "one oil does it all" solution that I can run year round.

Can anyone suggest a better alternative than the 8100?

ringmaster · Jul 11, 2005

Oh no

In an old topic Tooslick wrote:

quote:

ANY 0w-40 will shear like crazy in ANY turbo (it has to), so 0w-40 in a turbo is "contra-indicated", as my doctor friends would say. It provides NO additional protection to an A3/B4 rated 10w30 - and the high polymer content leads directly to high temp piston deposits in the ring grooves and on the piston skirts.

Tooslick

This is bad news for me who had planned on using either XD-3 or 8100 0W40 in my highly stressed, high boost, high RPM Subaru turbo engine! Is it true? All the new Porsches (911 turbo, Cayenne, Carrera GT) run Mobil 1 0W40 from the factory....can 0W40 really be that bad?

DaveJ · Jul 11, 2005

I watched a Car & Driver Tv on Speed channel where they took a bone stock 2005 Forester XT and put a $6000 kit from a place called Moto GP or something like that. It made a STi killer out of a econo-box SUV. Over 400 HP, 6 speed, 18 inch rims and wide/low prof tires. Back to oils. I have a friend of the family that is doing a long term test on a 2004 WRX and Torco SR-1 5W20. He has done a few used oil analysis but I dont have the data, sorry. I do know he likes the extra power the Torco gave him over others he has tested. He is a driving fool and has over 45K miles on it. DaveJ

Palut · Jul 11, 2005

Ringmaster, the XD-3 Extra is designed for use in heavy duty, turbocharged diesel engines. While we haven't seen many used oil analysis of the XD-3 0W-40, I can't imagine an oil built to handle that kind of service would shear much.

Don't let the diesel ratings scare you off, they mean that the oil is better, not worse. As long as the oil's sulfated ash rating comes in at or below 1.5%, you don't need to worry.

I believe that the 0W-40 Tooslick refers to is the Mobil 1 0W-40 that's notorious for shearing down. It simply wasn't designed for use in a heavy duty application. It's designed for use in smaller gas engines, and doesn't need to be quite so robust.

Santo Fontana · Jul 11, 2005

quote:

Originally posted by y_p_w:
I wouldn't think so with the standard oil cooler (oil to coolant heat exchanger) which regulates the oil temps close to the thermostat temp. The filter mounts directly onto the cooler, and you should see an inlet/outlet for the coolant. I'd think that with the oil cooler, your oil temps might be lower than a NA 2.5 (w/o oil cooler) on a hot day.

In my experience the oil gets about 25f hotter than the coolant once warmed up. Driving on the highway I usually see 190f coolant temp and about 215f oil temps. Oil temp taken from plug in block under the intercooler and coolant temp from scan tool. (02 wrx)

Ziggyrama · Jul 12, 2005

I'm running 5W-40 Amsoil EU formula in my 04 WRX and the car runs awesome on it. I did not go through the winter with this oil yet but I do not anticipate any problems. I am also running 15psi of boost with a remapped ECU (Cobb stage I) versus 13.5 stock, so I am excercising my oil more then normal people would. I should get the test done to really know if things are ok but the car just sounds healthy and the power delivery is just awesome. This oil is supposed to be very sheer stable.

ringmaster · Jul 21, 2005

Thanks for the replies. Obviously I need an oil that is very sheer stable and some on here have suggested that oils with a wide spread (0W40) are not sheer stable, however I have no data to confirm or dispute this. My #1 pick thus far is the Motul 8100 0W40 which I think looks great on paper but maybe it isn't a good turbo oil? Another oil I've been looking at is the Motul BMW LL-01 5W30 since it is on the heavier side for a 30wt.

Can anyone else comment?

Garandman · Jul 22, 2005

quote:

Originally posted by ringmaster:
I have a brand new 2005 Forester XT ....

The car will be driven hard, in a far more spirited manner than most Foresters will ever be...think STi driver

....

Wow, I thought all the young, immature drivers bought VW Jettas....No worries as even breaking almost every motoring law, as long as you stop occasionally at stop signs and drive less than 40 mph over the speed limit you won't be stressing the engine at all like you might in a neighborhood Autocross. And btw since you are so spirited you might give competition driving a go and show everyone just how good you are.

Where do you live? The Subaru boxer motors can be very noisy in cold starts, because of the layout, differential expansion, and other reasons unknown.

Some oils result in disturbing cold start noises. Others don't. I'd post on ultimatesubaru.net and see what people have learned.

I have a 97 OBW with 156K miles on it, but it's a DOHC engine and not turbocharged. Just about any standard oil but Castrol was horrible on cold start.

ringmaster · Jul 23, 2005

quote:

Originally posted by Garandman:

quote:

Originally posted by ringmaster:
I have a brand new 2005 Forester XT ....

The car will be driven hard, in a far more spirited manner than most Foresters will ever be...think STi driver

....

Click to expand...

Wow, I thought all the young, immature drivers bought VW Jettas....No worries as even breaking almost every motoring law, as long as you stop occasionally at stop signs and drive less than 40 mph over the speed limit you won't be stressing the engine at all like you might in a neighborhood Autocross. And btw since you are so spirited you might give competition driving a go and show everyone just how good you are.

Where do you live? The Subaru boxer motors can be very noisy in cold starts, because of the layout, differential expansion, and other reasons unknown.

Some oils result in disturbing cold start noises. Others don't. I'd post on ultimatesubaru.net and see what people have learned.

I have a 97 OBW with 156K miles on it, but it's a DOHC engine and not turbocharged. Just about any standard oil but Castrol was horrible on cold start.

Thank you for taking the time to write one of the most useless posts ever! Young is relative, I am paid to instruct high performance track driving (need some lessons?) and I don't break the local traffic laws. So much for your brilliant and totally off topic assumptions

Can anyone else shed some light on which high quality, full synthetic oils I should consider for my 2.5L turbo Subie engine? Cost (up to $15L) is not an issue, I want the best oil available.

Thank you

melayout · Jul 23, 2005

I've got an 05 Legacy GT and I'm trying 5W-40 Mobil 1 Truck and SUV since 5/10W-30 is consumed too much to my liking under hard driving.

If you want the best, get some Motul, it's what the SWRT uses.

Edit: I switched to synthetic(Mobil 1 10w30) at 7500 miles.

AndyH · Jul 24, 2005

quote:

Originally posted by ringmaster:
Can anyone else shed some light on which high quality, full synthetic oils I should consider for my 2.5L turbo Subie engine? Cost (up to $15L) is not an issue, I want the best oil available.[/QB]

I's still suggest German Castrol Syntec 0w-30. I just filled my STi with this oil and so-far, so-good. Smooth running engine and a slightly quieter engine. Will see how it holds up over my planned 5,000 mile OCI. Should be readily available up there in Canada at Wal-Mart and Canadian Tire (I believe).

ringmaster · Jul 24, 2005

quote:

Originally posted by melayout:
I've got an 05 Legacy GT and I'm trying 5W-40 Mobil 1 Truck and SUV since 5/10W-30 is consumed too much to my liking under hard driving.

If you want the best, get some Motul, it's what the SWRT uses.

How much of the M1 30wt was your 2.5L consuming?

I am leaning towards Motul and so far my choice would be the 8100 0W40, however a few poster have suggested that any 0W40 is a poor choice (sheer wise I think) in a turbo engine

melayout · Jul 24, 2005

1qt/5k miles, then now in the summer it has gone up to 2-3qts/4k miles. According to the number of people bitching online and statistics, it seems almost all cases of significant oil consumption is with Mobil 1. Still I'm trying 5W-40 Mobil 1 because I like its excellent detergency and active additives.

Yeah 0W-40 is not very shear stable. If you specifically want a 40 weight, go for a 5W-40, but if you want a 40 weight because you're worried about oil consumption try a non-Mobil 1 5w30 or 10w30 oil first.

Garandman · Jul 27, 2005

Sir, where do you instruct high performance driving?
I took from your post and the fact it was a Forester that you were going to be driving it on the street.

The competition drivers and instructors I know drive quite cautiously on the street. When racing you know the driver next to you is not drunk, blind, or chatting on a cell phone.

Nonetheless YMMV in terms of cold starts and Subarus.

Subaru 2.5 STi/Forester - GC or XD-3 good?

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