I will never understand oil....
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This is essentially the reason why many of their vehicles are spec'd for 40 wt. oils. The ACEA sequences are designed for gasoline/diesel engines for lubricant availability purposes. If the U.S. had a similar mix of gas/diesel vehicles and the same availability issues, we would be running 40 wt. oil also. Engine wear protection has far more to do with design than the viscosity of oil. BTW, there is research in Europe to design diesel engines to run on 20 wt. They too have "CAFE" like requirements. Economy and environmental concerns/regulations are not just a U.S. issue.
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Originally Posted By: river_rat
I'm lost now...
I figure even 80°-90°F at start-up is "cold" to the oil, isn't it?
So isn't a 0W just that much better starting flow, even in the summertime? (if the oil is otherwise equal quality)
0w is describing the pumping properties of the oil @ -40F
If the "W" rating was some "otherwise always equal" deal, there would be absolutely no reason for NOT using a 40 weight across the board on any engine.
Now the 0w-X may have a broader VI that will make it easier to pump (less horsepower required/lost) when compared to a 5w- or 10w of the same grade ..but that difference is marginal compared to a 0w-20 vs. a 0w-40. The difference in visc between 40C and 100C is ....
Typical Properties
Mobil 1 0W-40
Value
Viscosity, ASTM D 445
cSt @ 40º C 78.3
cSt @ 100º C 14
Typical Properties
Mobil 1 0W-20
SAE Grade 0W-20
Viscosity, ASTM D 445
cSt @ 40ºC 45.5
cSt @ 100ºC 8.6
They're both "0w" oils. Yet the 0w-40 has a 40C visc that is 5.5 times as much as its 100C visc ...which is nearly twice as high as the 0w-20's 100C visc. Every step of the way ...in any sensible flow scenario ..that heavier oil will tax h.p. for h.p MORE than the lighter fluid. As you go colder the divergence between the two broadens.
Essentially if there are two fluids that have a 40C visc of equal numbers, you can throw the "W" out of the picture. At that point ..at that time, they're both taxing the engine to pump the stuff to the same level (mostly-some alterations may apply). That is, 60cSt is 60cSt @ xxyyz temp regardless if it's got a -00000000000000000W on the front end of it.
I'm lost now...
I figure even 80°-90°F at start-up is "cold" to the oil, isn't it?
So isn't a 0W just that much better starting flow, even in the summertime? (if the oil is otherwise equal quality)
0w is describing the pumping properties of the oil @ -40F
If the "W" rating was some "otherwise always equal" deal, there would be absolutely no reason for NOT using a 40 weight across the board on any engine.
Now the 0w-X may have a broader VI that will make it easier to pump (less horsepower required/lost) when compared to a 5w- or 10w of the same grade ..but that difference is marginal compared to a 0w-20 vs. a 0w-40. The difference in visc between 40C and 100C is ....
Typical Properties
Mobil 1 0W-40
Value
Viscosity, ASTM D 445
cSt @ 40º C 78.3
cSt @ 100º C 14
Typical Properties
Mobil 1 0W-20
SAE Grade 0W-20
Viscosity, ASTM D 445
cSt @ 40ºC 45.5
cSt @ 100ºC 8.6
They're both "0w" oils. Yet the 0w-40 has a 40C visc that is 5.5 times as much as its 100C visc ...which is nearly twice as high as the 0w-20's 100C visc. Every step of the way ...in any sensible flow scenario ..that heavier oil will tax h.p. for h.p MORE than the lighter fluid. As you go colder the divergence between the two broadens.
Essentially if there are two fluids that have a 40C visc of equal numbers, you can throw the "W" out of the picture. At that point ..at that time, they're both taxing the engine to pump the stuff to the same level (mostly-some alterations may apply). That is, 60cSt is 60cSt @ xxyyz temp regardless if it's got a -00000000000000000W on the front end of it.
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Use a visc calculator ..widman's. Just input the 40C/100C numbers and then plug in your desired temp.
http://widman.biz/English/Calculators/Operational.html
Assuming the calculator is debugged, 5w-20 Uniflo, with a 40C of 47cSt and a 100C of 8.3 would have a 22C visc of 107cSt.
http://widman.biz/English/Calculators/Operational.html
Assuming the calculator is debugged, 5w-20 Uniflo, with a 40C of 47cSt and a 100C of 8.3 would have a 22C visc of 107cSt.
Originally Posted By: sbergman27
Originally Posted By: Y_K
..to S-Bahn, sometimes on a bicycle.
I'm imagining Steve Austin and Jaime Sommers on a Bicycle Built For Two. I'm sure they'd surprise the Ferrari drivers, passing on the shoulder like that. ;-)
They'd burn out the bike tires!
Originally Posted By: Y_K
..to S-Bahn, sometimes on a bicycle.
I'm imagining Steve Austin and Jaime Sommers on a Bicycle Built For Two. I'm sure they'd surprise the Ferrari drivers, passing on the shoulder like that. ;-)
They'd burn out the bike tires!
Originally Posted By: Gary Allan
..but this is the 2nd time I've noted that the ONLY thing you see different between a 5w-20 and (let's go WILD) and a (proposed) 5w-60 is operating visc.
Well... oviously, it is a curve. And 40C and 100C kinematic numbers are really woefully inadequate to give us a clear picture of exactly what goes on. The curve can be extrapolated from those two points, albeit rather inaccurately.
Quote:
Most engines spend there entire lives in warm up and very few are at "operating visc" to a higher percentage of time than than they are warming up to "operating visc".
And you have data to support this claim? But let's not go off on too much of a tangent with this point because it is not the central one.
Quote:
You need to qualify that a bit more.
Why quality in this particular case? It would only cloud my meaning without clarifying anything pertinent. Because for almost the entirety of the warm up time, even 0w20 is going to be significantly thicker than, say, 0w40 is at operating temperature. (Check it out with the link I posted.) And I take the operating tempterature viscosity of the factory recommended oil to be the "desirable" viscosity for the engine. Anything thicker than that is thicker than desirable.
..but this is the 2nd time I've noted that the ONLY thing you see different between a 5w-20 and (let's go WILD) and a (proposed) 5w-60 is operating visc.
Well... oviously, it is a curve. And 40C and 100C kinematic numbers are really woefully inadequate to give us a clear picture of exactly what goes on. The curve can be extrapolated from those two points, albeit rather inaccurately.
Quote:
Most engines spend there entire lives in warm up and very few are at "operating visc" to a higher percentage of time than than they are warming up to "operating visc".
And you have data to support this claim? But let's not go off on too much of a tangent with this point because it is not the central one.
Quote:
You need to qualify that a bit more.
Why quality in this particular case? It would only cloud my meaning without clarifying anything pertinent. Because for almost the entirety of the warm up time, even 0w20 is going to be significantly thicker than, say, 0w40 is at operating temperature. (Check it out with the link I posted.) And I take the operating tempterature viscosity of the factory recommended oil to be the "desirable" viscosity for the engine. Anything thicker than that is thicker than desirable.
Originally Posted By: sbergman27
Because for almost the entirety of the warm up time, even 0w20 is going to be significantly thicker than, say, 0w40 is at operating temperature.
And note that Eneos 0w20, even with its impressive VI of 199, is still thicker than M1 5w50 is at 100C, all the way up to 65C (150F).
Because for almost the entirety of the warm up time, even 0w20 is going to be significantly thicker than, say, 0w40 is at operating temperature.
And note that Eneos 0w20, even with its impressive VI of 199, is still thicker than M1 5w50 is at 100C, all the way up to 65C (150F).
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Quote:
And you have data to support this claim? But let's not go off on too much of a tangent with this point because it is not the central one.
Common sense. Unless you figure that the entire mass rolling fleet operates form dead cold (however warm or cold that may be) on an average of 40 minutes each and every event, then the warm up event trumps the steady state operational "at temp" duration in the lion's share of the time.
That's not a stretch in anyone's imagination.
For more (non exchanged) engines than not, the total thermal saturation, as evidenced by time to steady state oil temp is about the same regardless of ambient temp. It will tend to hover around 12-15 miles or 20 minutes.
And you have data to support this claim? But let's not go off on too much of a tangent with this point because it is not the central one.
Common sense. Unless you figure that the entire mass rolling fleet operates form dead cold (however warm or cold that may be) on an average of 40 minutes each and every event, then the warm up event trumps the steady state operational "at temp" duration in the lion's share of the time.
That's not a stretch in anyone's imagination.
For more (non exchanged) engines than not, the total thermal saturation, as evidenced by time to steady state oil temp is about the same regardless of ambient temp. It will tend to hover around 12-15 miles or 20 minutes.
Originally Posted By: Gary Allan
Quote:
And you have data to support this claim? But let's not go off on too much of a tangent with this point because it is not the central one.
Unless you figure that the entire mass rolling fleet operates form dead cold (however warm or cold that may be) on an average of 40 minutes each and every event, then the warm up event trumps the steady state operational "at temp" duration in the lion's share of the time.
Like I said, I'm not really wanting to derail the main conversation in favor of this side-point. But... you're claiming that it takes >20 minutes to warm an engine up under average conditions? (World global mean air temperature at the surface of the earth is about 14C (57F). Please define "warm up". I suspect that your definition is going to include that last 1 degree increase of oil to its final running temperature. That last few degrees is likely to take quite some time. How long from start up to when it reaches 65C, the point at which 0w20 is the same viscosity as 5w50 is at 100C, I wonder?
At any rate, this is all really irrelevant to the main point, considering the fact that even 0w20 is thicker than optimal, even for engines which call for heavy oil, until the engine is very close to its normal operating temperature, as demonstrated in my previous post. A point which you have not addressed.
Quote:
And you have data to support this claim? But let's not go off on too much of a tangent with this point because it is not the central one.
Unless you figure that the entire mass rolling fleet operates form dead cold (however warm or cold that may be) on an average of 40 minutes each and every event, then the warm up event trumps the steady state operational "at temp" duration in the lion's share of the time.
Like I said, I'm not really wanting to derail the main conversation in favor of this side-point. But... you're claiming that it takes >20 minutes to warm an engine up under average conditions? (World global mean air temperature at the surface of the earth is about 14C (57F). Please define "warm up". I suspect that your definition is going to include that last 1 degree increase of oil to its final running temperature. That last few degrees is likely to take quite some time. How long from start up to when it reaches 65C, the point at which 0w20 is the same viscosity as 5w50 is at 100C, I wonder?
At any rate, this is all really irrelevant to the main point, considering the fact that even 0w20 is thicker than optimal, even for engines which call for heavy oil, until the engine is very close to its normal operating temperature, as demonstrated in my previous post. A point which you have not addressed.
Originally Posted By: sbergman27
Originally Posted By: Gary Allan
Quote:
And you have data to support this claim? But let's not go off on too much of a tangent with this point because it is not the central one.
Unless you figure that the entire mass rolling fleet operates form dead cold (however warm or cold that may be) on an average of 40 minutes each and every event, then the warm up event trumps the steady state operational "at temp" duration in the lion's share of the time.
Like I said, I'm not really wanting to derail the main conversation in favor of this side-point. But... you're claiming that it takes >20 minutes to warm an engine up under average conditions? (World global mean air temperature at the surface of the earth is about 14C (57F). Please define "warm up". I suspect that your definition is going to include that last 1 degree increase of oil to its final running temperature. That last few degrees is likely to take quite some time. How long from start up to when it reaches 65C, the point at which 0w20 is the same viscosity as 5w50 is at 100C, I wonder?
At any rate, this is all really irrelevant to the main point, considering the fact that even 0w20 is thicker than optimal, even for engines which call for heavy oil, until the engine is very close to its normal operating temperature, as demonstrated in my previous post. A point which you have not addressed.
I totally agree. The viscosity numbers speak for themselves. A 0w20 has cST in the thousands when at very cold temps. From an engine perspective, such high cST's are acceptable. Therefore, there is no reason to say that a cST in the hundreds at regular cold temps is really that bad and that a 0w20 oil is better than a 5w30 oil across all starting temps.
Technically you can say it is "better", but the fact that manufacturers, oil companies and owners are all starting their engine when viscosity is in the thousands of cST's suggests that it has no real world impact.
The same can be said of those who caution against a heavier weight oil because it won't flow quickly enough. A 15w50 will flow faster at normal operating temperature than a 0w20 would at 0c. So why wouldn't the thinner 15w50 reach all the engine parts it needs to when compared to the thicker 0w20?
Originally Posted By: Gary Allan
Quote:
And you have data to support this claim? But let's not go off on too much of a tangent with this point because it is not the central one.
Unless you figure that the entire mass rolling fleet operates form dead cold (however warm or cold that may be) on an average of 40 minutes each and every event, then the warm up event trumps the steady state operational "at temp" duration in the lion's share of the time.
Like I said, I'm not really wanting to derail the main conversation in favor of this side-point. But... you're claiming that it takes >20 minutes to warm an engine up under average conditions? (World global mean air temperature at the surface of the earth is about 14C (57F). Please define "warm up". I suspect that your definition is going to include that last 1 degree increase of oil to its final running temperature. That last few degrees is likely to take quite some time. How long from start up to when it reaches 65C, the point at which 0w20 is the same viscosity as 5w50 is at 100C, I wonder?
At any rate, this is all really irrelevant to the main point, considering the fact that even 0w20 is thicker than optimal, even for engines which call for heavy oil, until the engine is very close to its normal operating temperature, as demonstrated in my previous post. A point which you have not addressed.
I totally agree. The viscosity numbers speak for themselves. A 0w20 has cST in the thousands when at very cold temps. From an engine perspective, such high cST's are acceptable. Therefore, there is no reason to say that a cST in the hundreds at regular cold temps is really that bad and that a 0w20 oil is better than a 5w30 oil across all starting temps.
Technically you can say it is "better", but the fact that manufacturers, oil companies and owners are all starting their engine when viscosity is in the thousands of cST's suggests that it has no real world impact.
The same can be said of those who caution against a heavier weight oil because it won't flow quickly enough. A 15w50 will flow faster at normal operating temperature than a 0w20 would at 0c. So why wouldn't the thinner 15w50 reach all the engine parts it needs to when compared to the thicker 0w20?
Last edited:
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Quote:
Like I said, I'm not really wanting to derail the main conversation in favor of this side-point. But... you're claiming that it takes >20 minutes to warm an engine up under average conditions?
Under just about any conditions. Even a very high output chassis (non-exchanged/non forced cooled) ..FLOORED ..won't be able to reach a normalize/terminal temp due to being unable to sustain 20 minutes @ WOT to find out what that "steady state" is. It will surely exceed the 100C/212F spec of the oil.
Quote:
I suspect that your definition is going to include that last 1 degree increase of oil to its final running temperature.
Not mine. SAE's
Quote:
That last few degrees is likely to take quite some time.
The last few degrees (as in single digit increments) take a long time to pass.
Quote:
How long from start up to when it reaches 65C, the point at which 0w20 is the same viscosity as 5w50 is at 100C, I wonder?
Probably (in a non-exchanged engine) about the halfway mark. In my experience 155F-165f+/- would be at the 9 mile mark for an absolute cold start. That would mark the onset of "tapering off" of the rate of change. Up to that point it was fairly linear at least from 70F - to that point (gauge started @ 70F).
Quote:
At any rate, this is all really irrelevant to the main point, considering the fact that even 0w20 is thicker than optimal, even for engines which call for heavy oil, until the engine is very close to its normal operating temperature, as demonstrated in my previous post. A point which you have not addressed.
Why do I sense an argument when I've done nothing but agree with you?
Now if you want ME to extend that to lighter oils in heavier oil spec'd engine, I'll remind you that I use a 0w-10 oil in a spec'd 30 weight engine. I throw the whole thing out the window.
I have no problem with your assertion with proper qualifications.
Like I said, I'm not really wanting to derail the main conversation in favor of this side-point. But... you're claiming that it takes >20 minutes to warm an engine up under average conditions?
Under just about any conditions. Even a very high output chassis (non-exchanged/non forced cooled) ..FLOORED ..won't be able to reach a normalize/terminal temp due to being unable to sustain 20 minutes @ WOT to find out what that "steady state" is. It will surely exceed the 100C/212F spec of the oil.
Quote:
I suspect that your definition is going to include that last 1 degree increase of oil to its final running temperature.
Not mine. SAE's
Quote:
That last few degrees is likely to take quite some time.
The last few degrees (as in single digit increments) take a long time to pass.
Quote:
How long from start up to when it reaches 65C, the point at which 0w20 is the same viscosity as 5w50 is at 100C, I wonder?
Probably (in a non-exchanged engine) about the halfway mark. In my experience 155F-165f+/- would be at the 9 mile mark for an absolute cold start. That would mark the onset of "tapering off" of the rate of change. Up to that point it was fairly linear at least from 70F - to that point (gauge started @ 70F).
Quote:
At any rate, this is all really irrelevant to the main point, considering the fact that even 0w20 is thicker than optimal, even for engines which call for heavy oil, until the engine is very close to its normal operating temperature, as demonstrated in my previous post. A point which you have not addressed.
Why do I sense an argument when I've done nothing but agree with you?
Now if you want ME to extend that to lighter oils in heavier oil spec'd engine, I'll remind you that I use a 0w-10 oil in a spec'd 30 weight engine. I throw the whole thing out the window.
I have no problem with your assertion with proper qualifications.
A couple thing I noticed:
1) US have different fuel that gives different demand in oil quality (not as robust, cheaper to buy)
2) US have different population, who tends to overbuy torque so the engine doesn't work as hard (i.e. V6 3.5L is typical in US, but 1.6L is in Europe)
3) US have fuel economy requirement, so manufactures go for fuel economy rather than protection in the trade off.
1) US have different fuel that gives different demand in oil quality (not as robust, cheaper to buy)
2) US have different population, who tends to overbuy torque so the engine doesn't work as hard (i.e. V6 3.5L is typical in US, but 1.6L is in Europe)
3) US have fuel economy requirement, so manufactures go for fuel economy rather than protection in the trade off.
This may be useful for some. An update in almost done:
http://ferrarichat.com/forum/faq.php?faq=new_faq_item#faq_haas_articles
https://bobistheoilguy.com/forums/threads/link-to-aehaas-writings.18776/
aehaas
http://ferrarichat.com/forum/faq.php?faq=new_faq_item#faq_haas_articles
https://bobistheoilguy.com/forums/threads/link-to-aehaas-writings.18776/
aehaas
Originally Posted By: PandaBear
A couple thing I noticed:
1) US have different fuel that gives different demand in oil quality (not as robust, cheaper to buy)
2) US have different population, who tends to overbuy torque so the engine doesn't work as hard (i.e. V6 3.5L is typical in US, but 1.6L is in Europe)
3) US have fuel economy requirement, so manufactures go for fuel economy rather than protection in the trade off.
Great points. Point 3 works in a strange way though. In Europe, there is a (market driven) fuel economy requirement because the price of gas is so high. This means people buy smaller engines and smaller cars.
I also think that there is less sustained highway driving in Europe than US, and therefore the average mileage on an European car is less than an American car. So smaller engines fit the power and fuel economy requirements of the driving environment. I remember having a Saab Turbo rental in the UK and I could rarely do anything with it that exploited it's power. I have a 300hp car in the US and I find it useful every day I drive.
But this driving difference ie US mainly highway and long distance, Europe mainly city and short distance, together with smaller engines, I think means they favor heavier weight oils. The smaller engine and smaller car size achieves the fuel economy requirements, while the thicker oil does not impact it very much while making the car last longer.
And don't forget to add to the mix that there are more diesels and turbos.
A couple thing I noticed:
1) US have different fuel that gives different demand in oil quality (not as robust, cheaper to buy)
2) US have different population, who tends to overbuy torque so the engine doesn't work as hard (i.e. V6 3.5L is typical in US, but 1.6L is in Europe)
3) US have fuel economy requirement, so manufactures go for fuel economy rather than protection in the trade off.
Great points. Point 3 works in a strange way though. In Europe, there is a (market driven) fuel economy requirement because the price of gas is so high. This means people buy smaller engines and smaller cars.
I also think that there is less sustained highway driving in Europe than US, and therefore the average mileage on an European car is less than an American car. So smaller engines fit the power and fuel economy requirements of the driving environment. I remember having a Saab Turbo rental in the UK and I could rarely do anything with it that exploited it's power. I have a 300hp car in the US and I find it useful every day I drive.
But this driving difference ie US mainly highway and long distance, Europe mainly city and short distance, together with smaller engines, I think means they favor heavier weight oils. The smaller engine and smaller car size achieves the fuel economy requirements, while the thicker oil does not impact it very much while making the car last longer.
And don't forget to add to the mix that there are more diesels and turbos.
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Originally Posted By: Benzadmiral
Originally Posted By: sbergman27
Originally Posted By: Y_K
..to S-Bahn, sometimes on a bicycle.
I'm imagining Steve Austin and Jaime Sommers on a Bicycle Built For Two. I'm sure they'd surprise the Ferrari drivers, passing on the shoulder like that. ;-)
They'd burn out the bike tires!
I see I'm not the only one stuck on the idea of Steve Austin on a bicycle. Move over Lance, we have a new world champion cyclist.
Originally Posted By: sbergman27
Originally Posted By: Y_K
..to S-Bahn, sometimes on a bicycle.
I'm imagining Steve Austin and Jaime Sommers on a Bicycle Built For Two. I'm sure they'd surprise the Ferrari drivers, passing on the shoulder like that. ;-)
They'd burn out the bike tires!
I see I'm not the only one stuck on the idea of Steve Austin on a bicycle. Move over Lance, we have a new world champion cyclist.
Hi Gary,
I agree with everything you've said.
But I will add that the SAE grading system has been criticized on a number of fronts particularily in classifying many upscale synthetic oils.
An example of that is the synthetic Bruceblend 0W-10 oil you've been running in an engine spec'd for a 30wt. It sounds extreme but on closer examination not really. You've mentioned before that the estimated HTHS vis for the custom oil to be around 2.6 cP which is typical of many 20wt oils. Since the HTHS vis correlates better with actual operating viscosity than the kinematic 100C viscosity spec', the reality is your running an oil with the operating viscosity of a 'fresh' 20wt oil.
A 30wt oil must have a virgin HTHS vis >2.9 cP. Since most auto manufactures allow for at least 10% shear, that >2.9 cP specified oil could shear down into the 2.6 cP range before condemnation, or to the point where your presumably shear stable 0W-10 has started.
To answer the OP's question, most modern passenger car engines have similar operating viscosity requirements.
Different oil grades are recommended to cover a variety of operating conditions that can affect the minimum operating viscosity requirements for a particular engine in widely varing conditions.
Porsche, to site one example spec's M1 0W-40 for all it's vehicles regardless os specific output. Do Porsche engine require a 40wt oil, in a word no. Porsche will allow a 16% shear before condemnation. So that fresh HTHS vis of 3.7 cP would still lubricate adequately after having sheared to 3.1 cP; the viscosity of M1 5w30 when fresh.
The problem with starting with the lighter oil is all about safety margin. If you don't routinely drive down the autobahn at 300 km/h and you are familar with what the minimum oil pressure
is for engine and you keep an eye on it, then yes a 30wt or lighter oil may be all you need. For most people it's a whole lot easier to stick with the 0W-40.
I agree with everything you've said.
But I will add that the SAE grading system has been criticized on a number of fronts particularily in classifying many upscale synthetic oils.
An example of that is the synthetic Bruceblend 0W-10 oil you've been running in an engine spec'd for a 30wt. It sounds extreme but on closer examination not really. You've mentioned before that the estimated HTHS vis for the custom oil to be around 2.6 cP which is typical of many 20wt oils. Since the HTHS vis correlates better with actual operating viscosity than the kinematic 100C viscosity spec', the reality is your running an oil with the operating viscosity of a 'fresh' 20wt oil.
A 30wt oil must have a virgin HTHS vis >2.9 cP. Since most auto manufactures allow for at least 10% shear, that >2.9 cP specified oil could shear down into the 2.6 cP range before condemnation, or to the point where your presumably shear stable 0W-10 has started.
To answer the OP's question, most modern passenger car engines have similar operating viscosity requirements.
Different oil grades are recommended to cover a variety of operating conditions that can affect the minimum operating viscosity requirements for a particular engine in widely varing conditions.
Porsche, to site one example spec's M1 0W-40 for all it's vehicles regardless os specific output. Do Porsche engine require a 40wt oil, in a word no. Porsche will allow a 16% shear before condemnation. So that fresh HTHS vis of 3.7 cP would still lubricate adequately after having sheared to 3.1 cP; the viscosity of M1 5w30 when fresh.
The problem with starting with the lighter oil is all about safety margin. If you don't routinely drive down the autobahn at 300 km/h and you are familar with what the minimum oil pressure
is for engine and you keep an eye on it, then yes a 30wt or lighter oil may be all you need. For most people it's a whole lot easier to stick with the 0W-40.
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Quote:
A 30wt oil must have a virgin HTHS vis >2.9 cP. Since most auto manufactures allow for at least 10% shear, that >2.9 cP specified oil could shear down into the 2.6 cP range before condemnation, or to the point where your presumably shear stable 0W-10 has started.
Good point. It may be more of a sensational notation difference than anything material/physical.
Quote:
To answer the OP's question, most modern passenger car engines have similar operating viscosity requirements.
Different oil grades are recommended to cover a variety of operating conditions that can affect the minimum operating viscosity requirements for a particular engine in widely varing conditions.
Our typical response is to retain the same spec, but up the refresh rate. The difference between most North American spec's and Euro's is that we tend to vary the service length, while they (used to, anyway) just buffer the lubricant spec to cover the margins at the same interval with time being an ultimate limiting factor.
A 30wt oil must have a virgin HTHS vis >2.9 cP. Since most auto manufactures allow for at least 10% shear, that >2.9 cP specified oil could shear down into the 2.6 cP range before condemnation, or to the point where your presumably shear stable 0W-10 has started.
Good point. It may be more of a sensational notation difference than anything material/physical.
Quote:
To answer the OP's question, most modern passenger car engines have similar operating viscosity requirements.
Different oil grades are recommended to cover a variety of operating conditions that can affect the minimum operating viscosity requirements for a particular engine in widely varing conditions.
Our typical response is to retain the same spec, but up the refresh rate. The difference between most North American spec's and Euro's is that we tend to vary the service length, while they (used to, anyway) just buffer the lubricant spec to cover the margins at the same interval with time being an ultimate limiting factor.
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