cster

Is this spec oil good for a PPP STI 2.5 engine?
Cheers

JohnD

iTrader: (5)

5W/30 is the handbook recommendation for the newage engine, although few on here would actually consider using it!
The generally accepted minimum is 5w/40 and 10w/40 or 10w50 for modified or hard used engines.
JohnD

cster

Cheers for that.

harvey

iTrader: (48)

I suggest you are at risk with that oil. 5W-30 as a minimum but I would use 5W40 or 10W 40, at least in the summer.

reiddo

I am just about to get my 2002 bugeye sti serviced with subaru before getting it remapped. I asked for fully synthetic and they said they will put 5w-30 in it. It is currently running at 300bhp and should reach 330bhp after mapping. I thrash the car a lot so think I will go buy 5ltrs of oil and give to subaru to put in it. From what i read on here 5w-30 is minimum but what should i buy to put in it?

mobil 1 seems to be a good choice but which one...

Mobil 1 5W-30
Mobil 1 10W-30
Mobil 1 15W-50
Mobil 1 High Mileage 10W-30
Mobil 1 High Mileage 10W-40

I'm leaning towards 10W-30 but any advice appreciated

cster

It seems to me that the lower number is more representative of the oils "natural" viscosity and the higher number represents the change (increase) in viscosity caused by additives which increase viscosity at higher temperatures.
It seems therefore that the higher the difference between the two numbers, the more additives have been used.
Are these additives long molecular chains which open up at high temperatures to increase viscosity?
The reason I ask, is that it seems to me that these chains would be subject to chemical/mechanical breakdown and so with time the upper temperature viscosity will drop off.
Does anyone know if this is correct - I am no expert.

JohnD

iTrader: (5)

The only actual full-synthetic I recognise in your list is the 15w/50
For summer use I would suggest something like Millers CFS 10/40 or Silkolene Pro-S 10/50 if you can get some.
The 30 part indicates the viscosity characteristics at 100degC i.e THIN! Keep the second part of the grade minimum 40


JohnD