Mobil 5w20 vs AFE 0w20 question

[buck91]

Looking at the spec sheets from Mobil these oils look extremely similar (as expected). cSt @ 100C 8.7 vs 8.9 and cSt @ 40C 49.8 vs 44.8. They list a TBN on AFE as 8.8 but do not list one for M1 5w20. Am I missing anything or are these basically the same oils? I have a full change of M1 5w20 on the shelf for my truck, and just picked up an extra 6qts of AFE at costco for about $25. Was planning on running the 6qts of AFE plus 1-2 toppers of 5w20 this winter, but looking at the specs it seems to just not matter...

 

[HTSS_TR]

Both are 20 weight therefore viscosity at operating temperature is similar, AFE has higher VI so viscosity at cold start is thinner.

 

[147_Grain]

....and AFE 5W-20 is slightly more shear stable.

0W-20 will perform better in the cold Michigan winters due to its lighter basestock which helps it flow better below zero. 5W-20 has a small edge in the summer, but either oil really doesn't matter much in the warmer.months.

 

[JR]

AFE last winter between up and thumb of Michigan. On those 25-30below mornings there was a noticeable difference over dino 5w-20.


Harvey

 

[rfeir]

No matter where you live, a 0W oil will pump a lot faster on startup. Most engine wear takes place during its initial startup.

 

[lubricatosaurus]

Originally Posted By: rfeir
No matter where you live, a 0W oil will pump a lot faster on startup. Most engine wear takes place during its initial startup.
I think you're right. It must be low temperatures that don't yet allow ZDDP to plate-up on the surface. Evidence is from http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3877139/Re:_Toyota_0w20_syn__10756_mil
which is kind of typical low iron PPM wear on a Prius, where the engine spends all day starting/stopping, yet the oil may stay kinda hot.

 

[Clevy]

Originally Posted By: rfeir
No matter where you live, a 0W oil will pump a lot faster on startup. Most engine wear takes place during its initial startup.



Absolute and complete nonsense.

A 0w isn't going to pump faster than a 10w when ambient temps are typical summer for example.
And even as the temps approach freezing there is very little difference. Why you may ask. Because a positive displacement pump moves the same volume of oil regardless of ambient temps(until extreme winter temps move in)
So on that point your wrong.
Next is wear at start up. Wrong again.
An engine wears most during warm up,not start up. Why you may ask. Because at start up the oil is very thick.so it creates a hydrodynamic layer. However during warm up this layer thins and because the anti-wear agents require heat to activate the warm oil doesn't do much.
So your wrong on both points.

 

[Clevy]

Originally Posted By: lubricatosaurus
Originally Posted By: rfeir
No matter where you live, a 0W oil will pump a lot faster on startup. Most engine wear takes place during its initial startup.
I think you're right. It must be low temperatures that don't yet allow ZDDP to plate-up on the surface. Evidence is from http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3877139/Re:_Toyota_0w20_syn__10756_mil
which is kind of typical low iron PPM wear on a Prius, where the engine spends all day starting/stopping, yet the oil may stay kinda hot.



Exactly my point. The hot oil has the additive package activated so it's doing its job. The many start/stop cycles aren't contributing to any real wear.

Kinda cans both his theories.

But that's why bitog is here. To smash oil myths and help teach.
Now if only those who hold these myths dear would learn something.

 

[Shannow]

Originally Posted By: rfeir
No matter where you live, a 0W oil will pump a lot faster on startup. Most engine wear takes place during its initial startup.


Nope, at the limits of pumpability, which is what the "W" rating is there for, an appropriate versus inappropriate choice will certainly pump better/quicker.

But at freezing temperatures, or a summer's day, the 0W WILL NOT pump faster, let alone "a lot faster" than the 5W.

As to wear, that occurs in the initial minutes of engine operation, not the few seconds between cranking and the oil light going out. It occurs even though the oil is pressurised and flowing.