Widman viscosity graph

[Audi Junkie]

I can get SynPower 0w-20 within walking distance.


As for different w ratings and viscs, there is a lot of misunderstanding out there. Some viscs lines cross twice!

 

[sunfire]

Originally Posted By: Audi Junkie
I can get SynPower 0w-20 within walking distance.


Where?

 

[Audi Junkie]

A Speed Shop chain in PA, A&A. Some VR-1 Synth oils, Roush SynPower, a lot of oddball performance oils.

 

[Audi Junkie]

fwiw, PP 5w-30 is thinner than M1 0w-30.

 

[zoomzoom]

I wish that oil companies would give us viscosity for their oil at 0C as well

 

[CATERHAM]

Captain Howdy, your RP XPR 0W-10 PDS fig's are incorrect.
The correct spec's are:
Vis @ 100C is 6.5 cSt
Vis @ 40C is 35.2 cSt
VI .......... 140

 

[Captain Howdy]

Well now, that changes everything. I'm not surprised at my error. I was attempting to cross reference using the viscosity chart. Thanks a bunch for the numbers.

 

[CATERHAM]

Your welcome.
I saw your UOA posting on this oil and others.
I see you've modified your '02 Sentra; larger capacity sump etc.
Did you install an oil temp gauge? Do you know what sort of oil temp's you generally see?
What size and type of engine do you have? Estimated power and rev range?

 

[Jim 5]

Originally Posted By: Bryanccfshr
I agree, Very low Viscosity index. You ought to run the minimum temperature to -35Celsius . 0 is simply the freezing point.


I would like to see this as well. My cars see -35C in the winter time, and they all sit outside. 0w-20 is looking pretty good though.

 

[XS650]

Originally Posted By: Jim 5
Originally Posted By: Bryanccfshr
I agree, Very low Viscosity index. You ought to run the minimum temperature to -35Celsius . 0 is simply the freezing point.


I would like to see this as well. My cars see -35C in the winter time, and they all sit outside. 0w-20 is looking pretty good though.


If you extrapolate it that far below 40C it will be a meaningless number.

 

[Captain Howdy]

Originally Posted By: CATERHAM
Your welcome.
I saw your UOA posting on this oil and others.
I see you've modified your '02 Sentra; larger capacity sump etc.
Did you install an oil temp gauge? Do you know what sort of oil temp's you generally see?
What size and type of engine do you have? Estimated power and rev range?



The engine is the Nissan 2.5L QR25DE. With mods I'm guessing 165 horses at the wheels. The rev tops out at 6250.

I did install oil pressure and temp gauges. They're mounted about half way up the block using an adapter. Both gauges lead to the adapter. The pressure gauge seems to work fine. Starting at about 80 to 90 pounds and settling to 20 pounds when at full temp. The 0w-10 weight oil settled slightly lower than the 0w-20.

I don't have much confidence in the temp gauge. Especially in the winter. But on the highway in summer it runs at 180 F. From the highway to city traffic it will go over 200 f. It seems pretty worthless in the winter, hardly ever reaching over 140 F. I should have had it mounted in the oil pan.

 

[CATERHAM]

Thanks Captain.
You're right the best location for the oil temp sensor is the bottom of the sump. If you have a horizontal drain plug, drilling out the plug for the sensor works well.
Having said that, your oil temp readings sound about right. My temps in my Caterham and Bimmer show a similar pattern.
About 180F on the street and that can take 1/2 hour of highway speeds to attain and in the winter it's very hard to get any temperature into the oil.
If the people on this website knew that in all likelihood the oil temps in normally aspirated engines frequently does not get to the optimum 210F I think there would be less resistance to 20 wt oil.
At 180F the operational kinematic viscosity of the PP 0W-20 is 12.6 cSt using the Widman chart or effectively a light 40 wt oil and at 140F it's 21.9 cSt, a 60 wt oil. So, in effect the PP 0W-20 is too heavy an oil in your Sentra and very much so in the winter.
The RP 0W-10 was actually a good choice being effective a 30 wt (9.7 cSt) oil at 180F but still too heavy at 140F effectively a 50 wt (17.5 cSt) oil.