Presentation and questions about a STi

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Jun 14, 2004
Hi all!

This is my firts post in this fantastic forum. I write from Europe and I would like to increase my knowledges on lubricants and so...

I have been reading long this forum and I would like you to help me choosing the best motor oil lubricant for my aplication.

I own MY03 European Impreza STi (2.0l turbo, 265 bhp stock)that would have in few weeks a turboback system, sport air filter and a reflash (~330 bhp expected). I come from a "thick-is-better" comunity, but after reading and learning (?) a lot I think I have surpassed it.

By the moment I have been useing Mobil1 with Supersynth 5w-50. First change done with 2.000 miles, the next two at 5.000 miles (each one).

The climate where I live is not too hot nor too cold, in spite of the track days can even be with very high temps even 35-40cº ambient temp(its a different area).
The car is a daily driver (at least 70 highway miles every day, usually very softly driven here, around 3000 rpm´s), with few tracks days during the year, and its also hardly driven often.

I would like to advance to a 0w-30 (the "prefered" is a 5w-30 according to the manual)as long as I can buy here the Castrol SLX 0w-30 (wich I asume that is the GC
) but here is quite expensive (88$ 4 liters) and I would like to know if there are other options.
Please note that the M1 0w-30 Racing is not available in Europe. Whould the standar M1 0w-30 be recomendable? or the Castrol RS 0w-40? any other? Would be woth it to buy the M1 R to USA? is it api aproved (I want to keep the warranty)?
Whould be the oil comsumption higher on a 0w-30? can be the oil change intervals be extended?

Thanks in advice!

[ June 22, 2004, 06:55 AM: Message edited by: tharoka ]

I think the more you read here the more you will find that there are no solid answere on a lot of questions without seeing how the particular oil does in your car, under your driving conditions and your climate.

Its pretty hard to ignore the good results of Mobil 1 especially 10W-30. And since you live in a moderate climate this could be a good choice to start with. I hasten to point out that I am not pushing Mobil 1-I have moved away from it only bc I like the Schaeffer's Blend.

Personally I see no reason to go with the 0W in your climate except for the fact that the German Castrol is 0W-30 . Sorry I don't know if that is the same as the SLX (you could do a search). I'm not sure you really require the Mobil 1 racing oil.

Are you using the 5W-50 or is that a misprint. 50 wt. seems like too thick an oil and I personally would have broken the car in on a lighter oil and posphoned track days a little longer. But that's just me.

So I guess my suggestion would be to perhaps go with the German Castrol or Mobil 1 10W-30 and do an oil analysis. You can then go from there.

Sorry for the rambling.

Al, it´s not a misprint, it is M1 with SS 5w-50. The reason of why I have choose this oil is that the whole European Impreza comunity doesn´t recomend anything less than a 15/50, 10/60 (they take you as you were crazy if you speack about a 0w-40, so with a 0w-30...) But then you begin to learn how the lubricant works and to distingish the myths from the facts. So because of M1 is very reputated, I have choose a "safe" option.

Anyway, since the biggest wear in the motor life happens during it is getting warm, why would you recomend a 10w-x?

Anyway, would be the oil consumtion vary too much between a 0w-30/10w-30 to my actual 5w-50? and as long as the most of 0w-30 are for long-life kind of services, wich usually indicated very long oil change periods (till 18000 miles in my fathers A4 2.5 tdi V6, for example), it would be possible to extend the oil change intervals (maybe till 7000 milles)?

I have no options to do oil analysis, so I need to get feedback by the moment.

Another point is that the car has not track`ed yet but it would be soon

If rambling=long post, no probs, look at mines!
For your car, this would be my preference with M1 Full Synthetic oils, with #1 being my top choice:

1# 5W-40 (Truck & SUV or Delvac)
#2 0W-40
#3 10W-30

I would not use M1 0W-30 with your turocharged engine, but German Castrol (GC)would be excellent. I have two Saabs (turbo like you) and it requires ACEA A3 rated oil. If your's does too, then read the labels.
Apologies, duplicated post

[ June 22, 2004, 09:46 AM: Message edited by: tharoka ]
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