The IVA temperature is on the sweet spot of wear.
What's happening to our wedge when...
- Thread starter riggaz
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Originally Posted By: Clevy
I'm going the other way with this actually. The latter would be better. I don't think the viscosity index is as important as matching the oil to operating conditions rather than going thicker with a higher viscosity index.
VI means that the oil is "less wrong" at all other temperatures...as long as it holds up.
Lower VI oils will warm quicker, as they have greater internal friction.
I'm going the other way with this actually. The latter would be better. I don't think the viscosity index is as important as matching the oil to operating conditions rather than going thicker with a higher viscosity index.
VI means that the oil is "less wrong" at all other temperatures...as long as it holds up.
Lower VI oils will warm quicker, as they have greater internal friction.
Originally Posted By: Shannow
VI means that the oil is "less wrong" at all other temperatures...as long as it holds up.
That's a great way of stating that.
Originally Posted By: Shannow
Lower VI oils will warm quicker, as they have greater internal friction.
Good point.
This thread reminds me of the old days of BITOG!
VI means that the oil is "less wrong" at all other temperatures...as long as it holds up.
That's a great way of stating that.
Originally Posted By: Shannow
Lower VI oils will warm quicker, as they have greater internal friction.
Good point.
This thread reminds me of the old days of BITOG!
Originally Posted By: Shannow
Originally Posted By: Clevy
I'm going the other way with this actually. The latter would be better. I don't think the viscosity index is as important as matching the oil to operating conditions rather than going thicker with a higher viscosity index.
VI means that the oil is "less wrong" at all other temperatures...as long as it holds up.
Lower VI oils will warm quicker, as they have greater internal friction.
Alright.
So because a higher vi oil is closer to optimal viscosity and is thereby easier to pump and moves faster cold.
A lower viscosity oil is harder to pump,has more resistance to flow until hot which adds to total friction and with therefore heat up faster because it requires more energy to get to optimal,and that energy is absorbed by the oil as heat.
Am I close?
So the example above then which would be more desirable of the 2 options given?
The lower viscosity index oil or the higher,but thicker one.
Originally Posted By: Clevy
I'm going the other way with this actually. The latter would be better. I don't think the viscosity index is as important as matching the oil to operating conditions rather than going thicker with a higher viscosity index.
VI means that the oil is "less wrong" at all other temperatures...as long as it holds up.
Lower VI oils will warm quicker, as they have greater internal friction.
Alright.
So because a higher vi oil is closer to optimal viscosity and is thereby easier to pump and moves faster cold.
A lower viscosity oil is harder to pump,has more resistance to flow until hot which adds to total friction and with therefore heat up faster because it requires more energy to get to optimal,and that energy is absorbed by the oil as heat.
Am I close?
So the example above then which would be more desirable of the 2 options given?
The lower viscosity index oil or the higher,but thicker one.
Originally Posted By: riggaz
What's involved in the tests?
Good question.
Shannow. Have you got any links to any type of papers that describe and have results of different brands and grades.
Thanks in advance.
What's involved in the tests?
Good question.
Shannow. Have you got any links to any type of papers that describe and have results of different brands and grades.
Thanks in advance.
Originally Posted By: Clevy
Alright.
So because a higher vi oil is closer to optimal viscosity and is thereby easier to pump and moves faster cold.
A lower viscosity oil is harder to pump,has more resistance to flow until hot which adds to total friction and with therefore heat up faster because it requires more energy to get to optimal,and that energy is absorbed by the oil as heat.
Am I close?
So the example above then which would be more desirable of the 2 options given?
The lower viscosity index oil or the higher,but thicker one.
Assuming that you aren't at the limits of pumpability, and it's a plain, normal start at reasonable ambients, the oil pump will shift exactly the same amount per revolution for either low VI or high VI oil.
if both are in bypass on cold oil, the heat applied by the oil pump is exactly the same.
It's the work done in shearing the oil in the bearings and against cylinder walls that means that the oil that's thicker has greater drag.
Alright.
So because a higher vi oil is closer to optimal viscosity and is thereby easier to pump and moves faster cold.
A lower viscosity oil is harder to pump,has more resistance to flow until hot which adds to total friction and with therefore heat up faster because it requires more energy to get to optimal,and that energy is absorbed by the oil as heat.
Am I close?
So the example above then which would be more desirable of the 2 options given?
The lower viscosity index oil or the higher,but thicker one.
Assuming that you aren't at the limits of pumpability, and it's a plain, normal start at reasonable ambients, the oil pump will shift exactly the same amount per revolution for either low VI or high VI oil.
if both are in bypass on cold oil, the heat applied by the oil pump is exactly the same.
It's the work done in shearing the oil in the bearings and against cylinder walls that means that the oil that's thicker has greater drag.
Sometimes I think we try to extract too much information from VI
Too true...
and demonstrated by Chevron Phillips here, and summarised neatly in the chart that goes with it.
Both are same KV100, and both have identical KV40, and therefore have the same VI....but vastly different behaviours below freezing. Demonstrates clearly why viscosity calculators are pretty well wron.
But also draws into question why VI must use KV40 as the low point...rubbish hot day today, and the Nissan was still starting a little shy of it's KV40.
and demonstrated by Chevron Phillips here, and summarised neatly in the chart that goes with it.
Both are same KV100, and both have identical KV40, and therefore have the same VI....but vastly different behaviours below freezing. Demonstrates clearly why viscosity calculators are pretty well wron.
But also draws into question why VI must use KV40 as the low point...rubbish hot day today, and the Nissan was still starting a little shy of it's KV40.
Originally Posted By: Shannow
Originally Posted By: Clevy
Alright.
So because a higher vi oil is closer to optimal viscosity and is thereby easier to pump and moves faster cold.
A lower viscosity oil is harder to pump,has more resistance to flow until hot which adds to total friction and with therefore heat up faster because it requires more energy to get to optimal,and that energy is absorbed by the oil as heat.
Am I close?
So the example above then which would be more desirable of the 2 options given?
The lower viscosity index oil or the higher,but thicker one.
Assuming that you aren't at the limits of pumpability, and it's a plain, normal start at reasonable ambients, the oil pump will shift exactly the same amount per revolution for either low VI or high VI oil.
if both are in bypass on cold oil, the heat applied by the oil pump is exactly the same.
It's the work done in shearing the oil in the bearings and against cylinder walls that means that the oil that's thicker has greater drag.
Thank you Shannow.
Originally Posted By: Clevy
Alright.
So because a higher vi oil is closer to optimal viscosity and is thereby easier to pump and moves faster cold.
A lower viscosity oil is harder to pump,has more resistance to flow until hot which adds to total friction and with therefore heat up faster because it requires more energy to get to optimal,and that energy is absorbed by the oil as heat.
Am I close?
So the example above then which would be more desirable of the 2 options given?
The lower viscosity index oil or the higher,but thicker one.
Assuming that you aren't at the limits of pumpability, and it's a plain, normal start at reasonable ambients, the oil pump will shift exactly the same amount per revolution for either low VI or high VI oil.
if both are in bypass on cold oil, the heat applied by the oil pump is exactly the same.
It's the work done in shearing the oil in the bearings and against cylinder walls that means that the oil that's thicker has greater drag.
Thank you Shannow.
Originally Posted By: riggaz
What's involved in the tests?
Which tests precisely ?
Sequence IVA ?
http://www.infineum.com/sitecollectiondocuments/notebooks/gf5/establishedtests_sequence_iva.pdf
as bobbydavro said, the "sweetspot" for wear.
What's involved in the tests?
Which tests precisely ?
Sequence IVA ?
http://www.infineum.com/sitecollectiondocuments/notebooks/gf5/establishedtests_sequence_iva.pdf
as bobbydavro said, the "sweetspot" for wear.
Awesome thread guys
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