0W 20 v 5W 40

[Synack]

Originally Posted by bluesubie

+1. Even in racing or with an aftermarket turbo, I would go with a more robust 0W-20 or 5W-20 than jumping up in visocisty. Something like Motul 300V 0W-20 or Red Line 0W-20 and use used oil analysis to determine how the oil is holding up under the conditions.

The M1 0W-30 that Synack mentioned is a light 30 weight and will likely shear to a 20 weight under hard use anyway.

-Dennis

I've been told that newer synthetics do not shear.

[bluesubie]

Originally Posted by Synack

I've been told that newer synthetics do not shear.

Sometimes yes, sometimes no. You really have to do a used oil analysis to find out though. I did see one uoa on the M1 0W-30 (older API SM/GF4 forumula) in a Forester turbo with a Cobb Stage I and the oil didn't shear so I guess I should have said the oil may shear.

The newer GF-5 spec oils have been showing good uoa results in Subaru turbos, but it's tough to find data on them because everyone is afraid to do uoa's on these oils. There have been a few uoa's on WRX's with Pennzoil Ultra and Platinum popping up where the oil stayed in grade.

UOA's have shown the 20 weight oils have less shear than 30 weight oils. Likely due to a more stable base stock with less viscosity modifiers used in most 0W-30's or 5W-30's. Even Rotella T6 5W-40 has sheared to a 30 weight in WRX's. Even though a BRZ/FRS is naturally aspriated, the enemy of the oil will be fuel dilution due to the direct injection. I'm looking forward to seeing more uoa's with some mileage after a few oil changes.

And besides bumping up the oil weight/grade, you can also look for oils with the highest High Temp High Shear (found on the oil manufacturers web site). This is why German Castrol Syntec 0W-30 is so popular among enthusiasts where a 5W-30 is specced (maybe overkill in a 0W-20 application). European oil ACEA A3 oil specs require an HTHS of 3.5 or higher so the oil is more stable than one geared towards fuel economy. As a comparison, M1 0W-30 has an HTHS of 3.0, M1 0W-20 has an HTHS of 2.7, and M1 5W-20 has an HTHS of 2.75.
http://www.mobil.com/USA-English/Lub...l_1_5W-20.aspx

-Dennis

[Synack]

Right on

[Jimbo]

Originally Posted by Synack

UOA?

Yeah, but I'd be real surprised to see any meaningful difference between the two oils based on the analysis.

And if there was a difference it just could be that it was normal and would have happened with either oil.

-J

[SXE10]

If you know how to read a UOA then there will be lots of meaningful data there to compare two oils.
I think bluesubie explained it quiet well

[MSTiFK8R]

I got my DEFI oil press\temp gauge installed recently

using stock fill 0W20

On a warmed engine (90С\190F oil) engine runs 1-0,9 bar \ 13-14 psi oil pressure

On the road the oil pressure seems to follow the tacho pretty fast and pretty straightforward in most cases - 2K rpm for 2bar \ 30psi , 3 for 3bar and so on till the bypass at 6 bar \ 87 psi sharp , no matter how you redline the engine

of course, when it's cold, the oil press could be higher

I wonder how safe is running 13 psi idling on this waterish 0-20W

I got used to see 30+psi idling on my EJ20T's and EJ25T's , but the oil viscosity I used was never lower than 10-40, mostly 5-50 and 15-50

[BMWDavid]

Sounds fine. 10 psi per 1000 rpm is the standard thinking on oil pressure. 13-14 psi at an idle is fine and 87 psi at redline (7400) is plenty.

[killerkid08]

congrats, we are all proving nothing.

Running PU/ M1 5w-30, nothing less.

[Huehuecoyotl]

Originally Posted by MSTiFK8R

I got my DEFI oil press\temp gauge installed recently

would love to se a pic of your gauge!

[MSTiFK8R]

Originally Posted by Huehuecoyotl

would love to se a pic of your gauge!

you are welcome

[Huehuecoyotl]

That looks really nice with the red stitches. You do it yourself?