we get into the -20 F in wisconsin. LE won't work here in winter.

 

[QUOTE=xviper,Jun 7 2006, 10:31 AM] No, it doesn't make mention about any seasonal variation in diff fluid, but .............

He also made mention (at some point) that he doesn't recommend the LE when the car is operated in climates like mine where we routinely get sub freezing temps.

 

I wonder why they would use the (almost) boiling point of water (100*C) as the determination temp. Having monitored my diff temps under all sorts of driving conditions, I have never seen it go over 80*C (175*F) and most average driving scenarios, it's between 50*C to 70*C.
Can you explain what those numbers mean. Does it mean that the temp of the fluid must get up to 210 before you even see a viscosity of SAE 90? And for how long before you reach that temp, does the fluid stay "thick as molassus"? This is one area, I'm not well verse in.

 

xviper: got this from a google search

Viscosity: This is the SUS viscosity at 210 degrees. It is the standard SAE viscosity measure; SUS is the unit of viscosity. This value should remain within its grade, or plus or minus 20%, whichever is greater.

Dunno how "valid" it is..

 

xviper Posted on Jun 9 2006, 05:14 PM
This is the way I understand it: (I could be wrong)
Viscosity is a temperature related value and determines how the flowrate of a fluid behaves during temerature changes. IMO they picked 100C because celsius is the official temerature in science and 100 is .. kinda hot? They had to pick something.
One could measure (Kinematic) viscosity by letting the oil gravity drop through a small diameter tube, changing oil temperature gives different values.
Dynamic viscosity is the way the fluid particals themselfs are able / willing to move in relation to eachother, almost like transferring torque in our Torsen diff.
Anyway... SAE 90 says someting about how thick / thin that oil is at certain temps.
If you have 2 temperature points, cold and warm, you have 2 viscosity values, but I dont think you can draw a straight line between them, its curved, especially at the colder temps.

If you want to know how thick / thin an oil is at any given temperature you can't know that from SAE 90 alone, you will have to do a full temp range and take measurements.
I just picked up 2 bottles of LE-607, they were in the boot for half an hour driving home, it was 22 C outside. Berlina The fluid was certanly not as molasses, but also not as thin as my beloved 0W-40 I also put a bottle in the freezer (-18C) to see in the morning how thick it turns out to be.

 

[QUOTE=xviper,Jun 9 2006, 10:14 AM] I wonder why they would use the (almost) boiling point of water (100*C) as the determination temp.

 

does it matter if your FI assuming ther's more stress on the rear due to more power....... if so what diff oil is reccomened for FI s2k's?

 

You are beginning to seem more and more like me.
I once put two bottles of oil into the freezer just to see which one flowed better when cold. 10W30 dino oil and 10W30 synthetic. Nice to see I'm not the only one to do goofy things at home.

 

I don't believe I've ever seen any recommendations for rear diffs on F.I. S's.
I've been using the Mobil 1 75W90 synthetic all along and even under F.I. the analysis came back steller. I believe that attention to regular changes is just as important as what you use.

 

xviper: obviously you would reccomend mobil1 over redline?