This is a UOA from my car about a month ago.
Oil suggestions for supercharged Subaru BRZ
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Originally Posted By: Shannow
No, HTHS is the viscosity at 150C, and 10^6s^-1 shear rate...it's purely viscosity, not a "tendency" for anything
Originally Posted By: Shannow
The "minimum" HTHS specifications (well actually the HTHS specs themselves) only came into existance after multigrades were marketted, and some with excessive temporary shear properties caused problems.
Which is it? Were there tendencies of some oils to shear down, showing up on HTHS? Or not? You seem to be all over the place on this.
No, HTHS is the viscosity at 150C, and 10^6s^-1 shear rate...it's purely viscosity, not a "tendency" for anything
Originally Posted By: Shannow
The "minimum" HTHS specifications (well actually the HTHS specs themselves) only came into existance after multigrades were marketted, and some with excessive temporary shear properties caused problems.
Which is it? Were there tendencies of some oils to shear down, showing up on HTHS? Or not? You seem to be all over the place on this.
Originally Posted By: Cjsporl
This is a UOA from my car about a month ago.
That AFR ratio is not correct. This Run did not have the AFR sensor hooked up.
This is a UOA from my car about a month ago.
That AFR ratio is not correct. This Run did not have the AFR sensor hooked up.
Originally Posted By: ElastoHydro
Originally Posted By: Shannow
No, HTHS is the viscosity at 150C, and 10^6s^-1 shear rate...it's purely viscosity, not a "tendency" for anything
Originally Posted By: Shannow
The "minimum" HTHS specifications (well actually the HTHS specs themselves) only came into existance after multigrades were marketted, and some with excessive temporary shear properties caused problems.
Which is it? Were there tendencies of some oils to shear down, showing up on HTHS? Or not? You seem to be all over the place on this.
you need to brush up on reading and comprehension.
HTHS IS viscosity measured at at the specified shear rate.
HTHS came into being as with the advent of VIIs, oils had lower viscosities at higher shear rates, than at the KV style shear rates.
It was not a "tendency" (your words), they had different measured viscosities under different shear rates...which Newtonian fluids didn't.
Originally Posted By: Shannow
No, HTHS is the viscosity at 150C, and 10^6s^-1 shear rate...it's purely viscosity, not a "tendency" for anything
Originally Posted By: Shannow
The "minimum" HTHS specifications (well actually the HTHS specs themselves) only came into existance after multigrades were marketted, and some with excessive temporary shear properties caused problems.
Which is it? Were there tendencies of some oils to shear down, showing up on HTHS? Or not? You seem to be all over the place on this.
you need to brush up on reading and comprehension.
HTHS IS viscosity measured at at the specified shear rate.
HTHS came into being as with the advent of VIIs, oils had lower viscosities at higher shear rates, than at the KV style shear rates.
It was not a "tendency" (your words), they had different measured viscosities under different shear rates...which Newtonian fluids didn't.
Originally Posted By: Shannow
Originally Posted By: ElastoHydro
Originally Posted By: Shannow
No, HTHS is the viscosity at 150C, and 10^6s^-1 shear rate...it's purely viscosity, not a "tendency" for anything
Originally Posted By: Shannow
The "minimum" HTHS specifications (well actually the HTHS specs themselves) only came into existance after multigrades were marketted, and some with excessive temporary shear properties caused problems.
Which is it? Were there tendencies of some oils to shear down, showing up on HTHS? Or not? You seem to be all over the place on this.
you need to brush up on reading and comprehension.
HTHS IS viscosity measured at at the specified shear rate.
HTHS came into being as with the advent of VIIs, oils had lower viscosities at higher shear rates, than at the KV style shear rates.
It was not a "tendency" (your words), they had different measured viscosities under different shear rates...which Newtonian fluids didn't.
Shannow is confusing us. One minute we read HTHS is just another way to measure the same viscosity, then he says there is tendency for multi-grade oils to demonstrate shear as seen in the difference between KV100 and HTHS. There is a tendency for some oils to shear down more than others, and thats what HTHS tells us.
Originally Posted By: ElastoHydro
Originally Posted By: Shannow
No, HTHS is the viscosity at 150C, and 10^6s^-1 shear rate...it's purely viscosity, not a "tendency" for anything
Originally Posted By: Shannow
The "minimum" HTHS specifications (well actually the HTHS specs themselves) only came into existance after multigrades were marketted, and some with excessive temporary shear properties caused problems.
Which is it? Were there tendencies of some oils to shear down, showing up on HTHS? Or not? You seem to be all over the place on this.
you need to brush up on reading and comprehension.
HTHS IS viscosity measured at at the specified shear rate.
HTHS came into being as with the advent of VIIs, oils had lower viscosities at higher shear rates, than at the KV style shear rates.
It was not a "tendency" (your words), they had different measured viscosities under different shear rates...which Newtonian fluids didn't.
Shannow is confusing us. One minute we read HTHS is just another way to measure the same viscosity, then he says there is tendency for multi-grade oils to demonstrate shear as seen in the difference between KV100 and HTHS. There is a tendency for some oils to shear down more than others, and thats what HTHS tells us.
Originally Posted By: stickybuns
Originally Posted By: Shannow
Originally Posted By: ElastoHydro
Originally Posted By: Shannow
No, HTHS is the viscosity at 150C, and 10^6s^-1 shear rate...it's purely viscosity, not a "tendency" for anything
Originally Posted By: Shannow
The "minimum" HTHS specifications (well actually the HTHS specs themselves) only came into existance after multigrades were marketted, and some with excessive temporary shear properties caused problems.
Which is it? Were there tendencies of some oils to shear down, showing up on HTHS? Or not? You seem to be all over the place on this.
you need to brush up on reading and comprehension.
HTHS IS viscosity measured at at the specified shear rate.
HTHS came into being as with the advent of VIIs, oils had lower viscosities at higher shear rates, than at the KV style shear rates.
It was not a "tendency" (your words), they had different measured viscosities under different shear rates...which Newtonian fluids didn't.
Shannow is confusing us. One minute we read HTHS is just another way to measure the same viscosity, then he says there is tendency for multi-grade oils to demonstrate shear as seen in the difference between KV100 and HTHS. There is a tendency for some oils to shear down more than others, and thats what HTHS tells us.
The readers know the truth now. With Shannow talking out of both sides of his mouth at once, it was hard to tell. He might get better at this in the future, who knows.
Originally Posted By: Shannow
Originally Posted By: ElastoHydro
Originally Posted By: Shannow
No, HTHS is the viscosity at 150C, and 10^6s^-1 shear rate...it's purely viscosity, not a "tendency" for anything
Originally Posted By: Shannow
The "minimum" HTHS specifications (well actually the HTHS specs themselves) only came into existance after multigrades were marketted, and some with excessive temporary shear properties caused problems.
Which is it? Were there tendencies of some oils to shear down, showing up on HTHS? Or not? You seem to be all over the place on this.
you need to brush up on reading and comprehension.
HTHS IS viscosity measured at at the specified shear rate.
HTHS came into being as with the advent of VIIs, oils had lower viscosities at higher shear rates, than at the KV style shear rates.
It was not a "tendency" (your words), they had different measured viscosities under different shear rates...which Newtonian fluids didn't.
Shannow is confusing us. One minute we read HTHS is just another way to measure the same viscosity, then he says there is tendency for multi-grade oils to demonstrate shear as seen in the difference between KV100 and HTHS. There is a tendency for some oils to shear down more than others, and thats what HTHS tells us.
The readers know the truth now. With Shannow talking out of both sides of his mouth at once, it was hard to tell. He might get better at this in the future, who knows.
I'm not sure where the confusion lies. Shannow's point is clear. Years ago, there were multigrades that were exceedingly thin under operating conditions, and not by design. One could, at one time, have a 10w-40 that fulfilled the cold cranking requirements of a 10w-XX and the KV requirements of an SAE 40, yet had an HTHS of 2.9. In fact, that was allowed at one time.
Operational viscosity correlates very well with HTHS, and there is rather wide agreement on that point. HTHS can help discern the oil's operational viscosity, particularly in comparison to other examples of the same grade, yet quite different operating characteristics. GC 0w-30 and M1 0w-30 AFE are not functionally identical, with the former having a higher operational viscosity and higher HTHS, whereas the latter is thinner in practice and is a fuel economy type oil.
I wonder what the HTHS of a sockpuppet is.
Operational viscosity correlates very well with HTHS, and there is rather wide agreement on that point. HTHS can help discern the oil's operational viscosity, particularly in comparison to other examples of the same grade, yet quite different operating characteristics. GC 0w-30 and M1 0w-30 AFE are not functionally identical, with the former having a higher operational viscosity and higher HTHS, whereas the latter is thinner in practice and is a fuel economy type oil.
I wonder what the HTHS of a sockpuppet is.
Originally Posted By: Garak
I'm not sure where the confusion lies. Shannow's point is clear. Years ago, there were multigrades that were exceedingly thin under operating conditions, and not by design. One could, at one time, have a 10w-40 that fulfilled the cold cranking requirements of a 10w-XX and the KV requirements of an SAE 40, yet had an HTHS of 2.9. In fact, that was allowed at one time.
Operational viscosity correlates very well with HTHS, and there is rather wide agreement on that point. HTHS can help discern the oil's operational viscosity, particularly in comparison to other examples of the same grade, yet quite different operating characteristics. GC 0w-30 and M1 0w-30 AFE are not functionally identical, with the former having a higher operational viscosity and higher HTHS, whereas the latter is thinner in practice and is a fuel economy type oil.
Garak a nicely summed up and correct history lesson but it has nothing do do with this thread. That's why Shannow off topic remarks are confusing;
Back to the OP's query. With any significant performance mod' you would think an oil recommendation would be part of the package but that is not often the case.
Yes increasing the power 50% will usually just slightly increase the viscosity demands of a engine but that doesn't necessarily translate into the use of a heavier oil grade or an oil with a specific higher HTHSV rating.
The stock engine will tolerate very high oil temp's in excess of 275F without issue. The installation of one oil cooler I know of dropped the on track maximum oil temp's to 220-224F. That will result in a very large increase in operational viscosity at maximum possible oil temp's, more than enough I posit to deal with the power increase of the SC.
The all to common knee-jerk reaction of the inexperienced to blindly run or recommend a much heavier oil should be avoided. The questions one should be asking are, what will be the safe maximum oil temp' on the spec' (HTHSV 2.6cP OEM) oil or what minimum oil pressure at high rev's would represent a sufficient operational viscosity?
I'm not sure where the confusion lies. Shannow's point is clear. Years ago, there were multigrades that were exceedingly thin under operating conditions, and not by design. One could, at one time, have a 10w-40 that fulfilled the cold cranking requirements of a 10w-XX and the KV requirements of an SAE 40, yet had an HTHS of 2.9. In fact, that was allowed at one time.
Operational viscosity correlates very well with HTHS, and there is rather wide agreement on that point. HTHS can help discern the oil's operational viscosity, particularly in comparison to other examples of the same grade, yet quite different operating characteristics. GC 0w-30 and M1 0w-30 AFE are not functionally identical, with the former having a higher operational viscosity and higher HTHS, whereas the latter is thinner in practice and is a fuel economy type oil.
Garak a nicely summed up and correct history lesson but it has nothing do do with this thread. That's why Shannow off topic remarks are confusing;
Back to the OP's query. With any significant performance mod' you would think an oil recommendation would be part of the package but that is not often the case.
Yes increasing the power 50% will usually just slightly increase the viscosity demands of a engine but that doesn't necessarily translate into the use of a heavier oil grade or an oil with a specific higher HTHSV rating.
The stock engine will tolerate very high oil temp's in excess of 275F without issue. The installation of one oil cooler I know of dropped the on track maximum oil temp's to 220-224F. That will result in a very large increase in operational viscosity at maximum possible oil temp's, more than enough I posit to deal with the power increase of the SC.
The all to common knee-jerk reaction of the inexperienced to blindly run or recommend a much heavier oil should be avoided. The questions one should be asking are, what will be the safe maximum oil temp' on the spec' (HTHSV 2.6cP OEM) oil or what minimum oil pressure at high rev's would represent a sufficient operational viscosity?
Originally Posted By: CATERHAM
That's why Shannow off topic remarks are confusing;
Back to the OP's query.
You consider answering the OPS query WRT oil viscosity for HIS CURRENT engine with "use TGMO but redesign your engine with an oil cooler",,,to be "reamining on topic" ?
That's why Shannow off topic remarks are confusing;
Back to the OP's query.
You consider answering the OPS query WRT oil viscosity for HIS CURRENT engine with "use TGMO but redesign your engine with an oil cooler",,,to be "reamining on topic" ?
Originally Posted By: Shannow
Originally Posted By: CATERHAM
That's why Shannow off topic remarks are confusing;
Back to the OP's query.
You consider answering the OPS query WRT oil viscosity for HIS CURRENT engine with "use TGMO but redesign your engine with an oil cooler",,,to be "reamining on topic" ?
caterham is on topic. Whats your problem? These forums work better if you're not argumentative to the point of strange behavior. I agree with caterham's analysis in this case. His point about an oil cooler is excellent. That would allow the OP's Subaru to see street duty with higher fuel efficiency from a thinner oil while limiting the max oil temp on track day to prevent thermal gradients from stressing the daily-driver he has got a lot of money into.
Originally Posted By: CATERHAM
That's why Shannow off topic remarks are confusing;
Back to the OP's query.
You consider answering the OPS query WRT oil viscosity for HIS CURRENT engine with "use TGMO but redesign your engine with an oil cooler",,,to be "reamining on topic" ?
caterham is on topic. Whats your problem? These forums work better if you're not argumentative to the point of strange behavior. I agree with caterham's analysis in this case. His point about an oil cooler is excellent. That would allow the OP's Subaru to see street duty with higher fuel efficiency from a thinner oil while limiting the max oil temp on track day to prevent thermal gradients from stressing the daily-driver he has got a lot of money into.
Xw20 in a supercharged FA20 is a fool's move. There, I just said it. Period.
"Will it blow up?"
No, you want explosions, light some fireworks.
Unfortunately, accelerated engine wear is not as dramatic, sudden (or even noticeable) as some here would like. And further, it's not as obvious as glancing at a UOA either.
And due to the lack of a spectacular failure, others automatically take that proof that 20 "likely" should be "adequate" (contingent on bulk oil temperature and existence of backpressure, of course).
Ya, right. The first thing I want when I spend big bucks on engine power modifications is play russian roulette with FE-specific oil viscosities FOR THE THRILLS.
Are you kidding? You'd wager others' equipment on your on pride?
Subaru even goes out of their way to suggest a heavier grade when you drive hard or track their STOCK ASPIRATED ENGINE, but guys here want to embolden the OP to use 20 in a SUPERCHARGED version of that same engine, that Subaru advises an uprated viscosity even without any power adders.
Really?? Good luck with that.
"Will it blow up?"
No, you want explosions, light some fireworks.
Unfortunately, accelerated engine wear is not as dramatic, sudden (or even noticeable) as some here would like. And further, it's not as obvious as glancing at a UOA either.
And due to the lack of a spectacular failure, others automatically take that proof that 20 "likely" should be "adequate" (contingent on bulk oil temperature and existence of backpressure, of course).
Ya, right. The first thing I want when I spend big bucks on engine power modifications is play russian roulette with FE-specific oil viscosities FOR THE THRILLS.
Are you kidding? You'd wager others' equipment on your on pride?
Subaru even goes out of their way to suggest a heavier grade when you drive hard or track their STOCK ASPIRATED ENGINE, but guys here want to embolden the OP to use 20 in a SUPERCHARGED version of that same engine, that Subaru advises an uprated viscosity even without any power adders.
Really?? Good luck with that.
Originally Posted By: Shannow
Originally Posted By: CATERHAM
That's why Shannow off topic remarks are confusing;
Back to the OP's query.
You consider answering the OPS query WRT oil viscosity for HIS CURRENT engine with "use TGMO but redesign your engine with an oil cooler",,,to be "reamining on topic" ?
Installing an oil cooler has no more to do with "redesign your engine", than running a heavier than specified oil grade and it is a far better solution to high oil temp's.
Going into the history of 30 grade and 40 grade oils clearly has nothing to do with this thread.
Originally Posted By: CATERHAM
That's why Shannow off topic remarks are confusing;
Back to the OP's query.
You consider answering the OPS query WRT oil viscosity for HIS CURRENT engine with "use TGMO but redesign your engine with an oil cooler",,,to be "reamining on topic" ?
Installing an oil cooler has no more to do with "redesign your engine", than running a heavier than specified oil grade and it is a far better solution to high oil temp's.
Going into the history of 30 grade and 40 grade oils clearly has nothing to do with this thread.
Originally Posted By: boundarylayer
His point about an oil cooler is excellent. That would allow the OP's Subaru to see street duty with higher fuel efficiency from a thinner oil while limiting the max oil temp on track day to prevent thermal gradients from stressing the daily-driver he has got a lot of money into.
Because FE is his prime concern, that's why OP installed a SC, for better FE.
He's also going to change his tires to super hard, 175/80/13 for better FE.
And sure, why not! The differences are HUGE and the risk to the mechanicals is totally worth it, that's how much fuel he can potentially save sticking with 0w20...........
no, but seriously, RE: the bolded portion of the quote, google this term: "temperature rise"
His point about an oil cooler is excellent. That would allow the OP's Subaru to see street duty with higher fuel efficiency from a thinner oil while limiting the max oil temp on track day to prevent thermal gradients from stressing the daily-driver he has got a lot of money into.
Because FE is his prime concern, that's why OP installed a SC, for better FE.
He's also going to change his tires to super hard, 175/80/13 for better FE.
And sure, why not! The differences are HUGE and the risk to the mechanicals is totally worth it, that's how much fuel he can potentially save sticking with 0w20...........
no, but seriously, RE: the bolded portion of the quote, google this term: "temperature rise"
An oil cooler and xW-20 would be fine on track day. Its the temperature that thins oils out and makes it necessary to go high-viscosity if you don't have an oil cooler, just physics. I would have a tendency to go to a 10w-30 synthetic name brand though just to be sure, with or without an oil cooler. Maybe even add some LubroMoly MoS2 additive to be doubly sure.
Originally Posted By: jrustles
Originally Posted By: boundarylayer
His point about an oil cooler is excellent. That would allow the OP's Subaru to see street duty with higher fuel efficiency from a thinner oil while limiting the max oil temp on track day to prevent thermal gradients from stressing the daily-driver he has got a lot of money into.
Because FE is his prime concern, that's why OP installed a SC, for better FE.
He's also going to change his tires to super hard, 175/80/13 for better FE.
And sure, why not! The differences are HUGE and the risk to the mechanicals is totally worth it, that's how much fuel he can potentially save sticking with 0w20...........
no, but seriously, RE: the bolded portion of the quote, google this term: "temperature rise"
Wow, somebody is going nuts. Read what was said about lowering oil temperatures with an oil cooler. It keeps seals from frying and reduces hot spots. And learn not to be a douche.
Originally Posted By: boundarylayer
His point about an oil cooler is excellent. That would allow the OP's Subaru to see street duty with higher fuel efficiency from a thinner oil while limiting the max oil temp on track day to prevent thermal gradients from stressing the daily-driver he has got a lot of money into.
Because FE is his prime concern, that's why OP installed a SC, for better FE.
He's also going to change his tires to super hard, 175/80/13 for better FE.
And sure, why not! The differences are HUGE and the risk to the mechanicals is totally worth it, that's how much fuel he can potentially save sticking with 0w20...........
no, but seriously, RE: the bolded portion of the quote, google this term: "temperature rise"
Wow, somebody is going nuts. Read what was said about lowering oil temperatures with an oil cooler. It keeps seals from frying and reduces hot spots. And learn not to be a douche.
>going nuts
>douche
ya, so anyway, did you google temperature rise yet?
you also have to read the results
EDIT: okay, sorry, I'll try to be less of a douche and address what you wrote (clearly from not reading about temperature rise).
Originally Posted By: stickybuns
It keeps seals from frying
Seals? I didn't know frying seals was a problem. Yu'd think the Inuit peoples were getting their hands on frying pans
Quote:
and reduces hot spots. And learn not to be a douche.
But does it? Can an oil cooler reduce the amount of fuel being burned in the cylinder, and transmute the heat IMMEDIATELY and LOCALLY liberated in the process? Can stable BULK oil temperature reduce the crankpin forces/ringpack temps and impart a higher HTHSV into an oil?
>douche
ya, so anyway, did you google temperature rise yet?
you also have to read the results
EDIT: okay, sorry, I'll try to be less of a douche and address what you wrote (clearly from not reading about temperature rise).
Originally Posted By: stickybuns
It keeps seals from frying
Seals? I didn't know frying seals was a problem. Yu'd think the Inuit peoples were getting their hands on frying pans
Quote:
and reduces hot spots. And learn not to be a douche.
But does it? Can an oil cooler reduce the amount of fuel being burned in the cylinder, and transmute the heat IMMEDIATELY and LOCALLY liberated in the process? Can stable BULK oil temperature reduce the crankpin forces/ringpack temps and impart a higher HTHSV into an oil?
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Originally Posted By: jrustles
But does it? Can an oil cooler reduce the amount of fuel being burned in the cylinder, and transmute the heat IMMEDIATELY and LOCALLY liberated in the process? Can stable BULK oil temperature reduce the crankpin forces/ringpack temps and impart a higher HTHSV into an oil?
Originally Posted By: jrustles
>going nuts
>douche
Hmmm... Douche Nuts, I prefer Beer Nuts myself.
Levity. C'mon people in a bad mood, laugh a little.
An oil cooler sends cooler oil into the bearings, rings, all, so yes, more heat transfer from metal part to oil occurs. Yes the ring pack temps drop slightly too. Yes the working viscosity in the bearings is greater (you can't say HTHS visc because thats a test done at exactly 150 degC) using an oil cooler, thus increasing the oil film thickness compared to not using an oil cooler.
But does it? Can an oil cooler reduce the amount of fuel being burned in the cylinder, and transmute the heat IMMEDIATELY and LOCALLY liberated in the process? Can stable BULK oil temperature reduce the crankpin forces/ringpack temps and impart a higher HTHSV into an oil?
Originally Posted By: jrustles
>going nuts
>douche
Hmmm... Douche Nuts, I prefer Beer Nuts myself.
An oil cooler sends cooler oil into the bearings, rings, all, so yes, more heat transfer from metal part to oil occurs. Yes the ring pack temps drop slightly too. Yes the working viscosity in the bearings is greater (you can't say HTHS visc because thats a test done at exactly 150 degC) using an oil cooler, thus increasing the oil film thickness compared to not using an oil cooler.
And thus increasing the bearing drag, and reducing fuel economy...hmmm...
Given that the replacement rate of the oil in the ring belt is of the order of 10s of seconds to minutes (I posted a link to a paper a few weeks ago), I can't see a cooler materially altering the ring belt/cylinder wall temperatures.
Piston squirters may experience cooler oil tempatures, but covective heat transfer is related to T^2, with T measured in Kelivins (C+273), the percentage changes aren't anything like they could look if you think in degrees C
Given that the replacement rate of the oil in the ring belt is of the order of 10s of seconds to minutes (I posted a link to a paper a few weeks ago), I can't see a cooler materially altering the ring belt/cylinder wall temperatures.
Piston squirters may experience cooler oil tempatures, but covective heat transfer is related to T^2, with T measured in Kelivins (C+273), the percentage changes aren't anything like they could look if you think in degrees C
Elasto,
Oil coolers are a great idea, and no matter what, I wouldn't run any moderately powered engine without one.
But you're describing an abstract technicality, that specifically 'cooler' oil can take more heat before reaching it's breakdown point. No one can argue that. I mean, that's like Obama's "Change" slogan. Yeah, sure, 'change' is inevitable, regardless of whether he exists or not.
Change isn't always good or as promised.
Oil coolers don't generally cool oil any lower than NOT. They nominally stabilize oil temperatures@ around NOT when more heat is input into the bulk oil. The oil itself still has to be able to complete it's journey unscathed; perform under the heat and pressure in the first place before it can get back to it's 'safe haven' to be 'reborn' if you will.
I don't think stepping out of a meat freezer vs a sauna is going to make much of a difference if I subsequently jumped into an active volcano- my fragile meat-robot would get incinerated either way, even if they returned my corpse to the freezer (with a toe tag etc). Case in point? Mammals are unsuitable for volcanoes.
Likewise, all this compensation for using the AN INCORRECT VISCOSITY FOR THE APPLICATION is NOT going to give 0w20 any more durability in service, it'll still GOING to be abused by supercharged, high-RPM 4 cylinder duty; a fantastically different condition than a Prius ICE.
Originally Posted By: Shannow
Given that the replacement rate of the oil in the ring belt is of the order of 10s of seconds to minutes (I posted a link to a paper a few weeks ago), I can't see a cooler materially altering the ring belt/cylinder wall temperatures
Good point, that's like an eternity @ 400degrees
Oil coolers are a great idea, and no matter what, I wouldn't run any moderately powered engine without one.
But you're describing an abstract technicality, that specifically 'cooler' oil can take more heat before reaching it's breakdown point. No one can argue that. I mean, that's like Obama's "Change" slogan. Yeah, sure, 'change' is inevitable, regardless of whether he exists or not.
Oil coolers don't generally cool oil any lower than NOT. They nominally stabilize oil temperatures@ around NOT when more heat is input into the bulk oil. The oil itself still has to be able to complete it's journey unscathed; perform under the heat and pressure in the first place before it can get back to it's 'safe haven' to be 'reborn' if you will.
I don't think stepping out of a meat freezer vs a sauna is going to make much of a difference if I subsequently jumped into an active volcano- my fragile meat-robot would get incinerated either way, even if they returned my corpse to the freezer (with a toe tag etc). Case in point? Mammals are unsuitable for volcanoes.
Likewise, all this compensation for using the AN INCORRECT VISCOSITY FOR THE APPLICATION is NOT going to give 0w20 any more durability in service, it'll still GOING to be abused by supercharged, high-RPM 4 cylinder duty; a fantastically different condition than a Prius ICE.
Originally Posted By: Shannow
Given that the replacement rate of the oil in the ring belt is of the order of 10s of seconds to minutes (I posted a link to a paper a few weeks ago), I can't see a cooler materially altering the ring belt/cylinder wall temperatures
Good point, that's like an eternity @ 400degrees
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Originally Posted By: Shannow
Piston squirters may experience cooler oil tempatures, but covective heat transfer is related to T^2, with T measured in Kelivins (C+273), the percentage changes aren't anything like they could look if you think in degrees C
I think you mean 'convective' spelling. The amount of heat transfered is a function of the temperature difference. Piston squirters flow up to the pistons, then carry away some heat. You can argue about how much, yet in track applications especially, its enough to matter.
And to jrustles points above, remember that cooler oil (heat removed via oil cooler) results in cooler oil hitting all the metal inside the engine. At the mass flow rates involved, it can significantly reduce internal engine temperatures as CATERHAM already noted before.
Actually, I think everyone here agrees that cooler oil cools engines, sounds like the disagreement is whether it matters enough. I think it cools enough.
Piston squirters may experience cooler oil tempatures, but covective heat transfer is related to T^2, with T measured in Kelivins (C+273), the percentage changes aren't anything like they could look if you think in degrees C
I think you mean 'convective' spelling. The amount of heat transfered is a function of the temperature difference. Piston squirters flow up to the pistons, then carry away some heat. You can argue about how much, yet in track applications especially, its enough to matter.
And to jrustles points above, remember that cooler oil (heat removed via oil cooler) results in cooler oil hitting all the metal inside the engine. At the mass flow rates involved, it can significantly reduce internal engine temperatures as CATERHAM already noted before.
Actually, I think everyone here agrees that cooler oil cools engines, sounds like the disagreement is whether it matters enough. I think it cools enough.
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