Amsoil 5-40 European blend,Severe duty 75-90 in the diff, Synchromesh MTF in the tranny. Great stuff!

 

Mobile 1

 

Have any of you ever changed your engine oil?
And did it the proper way: with the oil being HOT?
Did you notice how thin the oil was pouring out the drain hole?
Did that scare you at all?
No?

Then why are you scared to use a 5W-30 or a 0W-30?
Because: "OMG, that's WAY to thin!!"
No it isnt!
Its just not too thick when cold

I'm not FI'd or anything.
If I was and I would have an oil cooled turbo I would use a proven full synthetic oil, 5W or 0W-30 and an oil cooler.
German Castrol 0W-30 is almost a 40 weight (when hot) and a true syn oil.
Good stuff.
Check out BITOG's page on GC:
http://www.bobistheoilguy.com/forums/ubbth...43&nt=8&fpart=1

 

Yes, I always change my oil while the oil is at minimum 130F or greater. I fail to see your point though?

I think what you are trying to say is that over 100C Castrol 0W-30 has a viscosity vs temperature curve that resembles 40 weight oil.


What I worry about is that the viscosity at my new average operating temperature. I am also interested in several other important points such as the flash point, the amounts of Zinc / Phosphorus and other material properties.

The problem is that even if you have all the variables such as average oil temperature you still have to get all the test data from the oil manufactures. For now I will continue to use 10W-30 Mobile 1. Form the published data I could find I could not find any material data that made the Amsoil better. In fact on paper Mobile looked to be the better choice.

The car is garage kept and not driven in the winter so a 5W oil would not be necessary or a smart choice. I may look into a 40 weight for summer operation if I do not add an oil cooler.

I did find infromation on the new Mobile Racing oil which looks promising.
http://www.mobiloil.com/USA-English/MotorO...acing_Oils.aspx

 

I try out different ones all the time. I think I have Rotella 10-40 at the moment.

 

dsddcd Posted on Dec 27 2008, 06:57 AM

That oil pouring out of the drain hole is pretty thin.
Because its hot / at operating temp (= 80-90C / 176-190F)
Now, for arguments sake lets say its 100C (all oil data is given at 40C and 100C)
If that oil is a xxW-30 oil it will be around 10.5 cSt.
cSt = centi Stoke = a way to describe kinematic (= flowing) viscosity.
Just remember: water H2O (at sea leavel at 20C) is 1 cSt.
That same fresh xxW-30 oil, pouring out of the bottle at room temp (20C) into your engine, will be around 145 cSt.
See ?
That's 14x as thick.
Is that a problem?
Will your engine self destruct when you start it?
No.
That same xxW-30 oil in the sump during a colder start (10C) will be around 250 cSt.
See ?
Is that a problem?
Not really, but your engine lives and works best with oil being 18! times as thin.

So my point was/is: 0W/5W oils aren't any thinner than 10W oils when at operating temp.
250 aint thinner than 10,5
They are (or better: can be) thinner during a cold start.

Now.. not all oils are the same and yes, it depends on the starting temps IF a 5W oil will be usefully thinner.
In fact, some 5W oils are thicker than 10W oils at 20C.
Oil formulations, base stocks, the list is endless, make every oil different and just by looking at the bottle one can not see how thick or thin it really is.
Full syn 0W-xx oils usually are thinner than their mineral (dino) counterparts.
Thinner across the board.

 

Nice Chart By the way, that info is not easy to find.

I am not concerned with the startup, there is enough Zinc/phosphorus or other additives in most oils that it is not an issue.

What I was trying to say is which Viscosity to use due to the elevated oil temperature s I am experiencing. My problem is how to choose the correct weight at my operating temperature. Hopefully the oil does not get above 200-240F during harder driving. If that is the case then I will have no problem sticking with the 30w.

I am probably more worried about the flash point and % sulfated ash. As the oil passes through the turbo I am sure it gets into the 300F range. I did find a nice reference at the link below. It is interesting to note that all the oils with no 0% Sulfated ash have no zinc. This is why I was interested in the newer Mobile racing oils. For the sake of talking it is important to note that with a catalytic converters you want to maintain lower levels of Zinc/phosphorus (ZDDP). Any oil with an "SL" or

 

Here is another off the shelf Mobile with ZDDP, that looks very promising. Just a note for everyone else stay clear of Energy/Fuel Concerving if you care more about your engine that catalytic converter.

http://www.mobiloil.com/USA-English/MotorO...il_1_0W-40.aspx

Your Castorl 0W-30 is also in the same category

 

To be honest I wouldn't focus too much on ZDDP levels as its
Found here:
http://www.sciencedirect.com/science?_ob=A...deb20afdc15da32
As far as I know ZDDP is used to reduce cam wear, especially the flat tapped cam designs and it helps in those area's during engine break-in.
Anyway's.. it's a boundry lubricant and the last thing you want is to have that happen to the parts that get more load being boosted: (IMO) crank & connecting rods.
Not so much (if at all) the cam shafts and "our" roller followers.

A proven true syn (grp IV & V base stock with low VI) in 0/5/10W-30 and an oil cooler would be what I would get.
For N/A cars the same, without the oil cooler.

 

go for 10-30