Do I want a high HT/HS or a low one?
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It's a compromise between fuel economy and engine protection.
Nothing has a larger impact on fuel economy than HTHS.
It's impact on engine wear depends on application.
Nothing has a larger impact on fuel economy than HTHS.
It's impact on engine wear depends on application.
Driving style primarily. All your cars spec a low hths oil for CAFE ECONOMY, but look for the hidden statement SOMEWHERE in the owners manual (there is such in my 08 Toyota manual) that states, '...for severe conditions such as towing or high speed operation in high ambient temperatures a higher grade oil is required to provide adequate engine protection.' This means to me that the specd 0w/5w30/20 oils DO NOT provide adequate protection for MY agressive driving style. How about you? Gary helped me discover that my spouse is a "closet" aggressive driver and has been killing engines left and right. She drives like a Q-Tip when I'm in the car - who woulda known?
And how did you find this out about you other driver ARCO?
My '07 Corolla originally calls for 5w30 in the owner's manual, with no conditional clause about requiring a higher viscosity oil. The TSB from Toyota that now recommends 5W-20 also does not recommend a higher viscosity oil for certain situations. My '07 Chrysler calls for 5W-20 only, and does not recommend a different viscosity oil for any condition, such as towing, etc.
ARCO, that statement in your manual may be particular to that particular engine design in your Yaris (what is it, the 1NZ-FE?), and may not apply to other situations.
I question the blanket speculation that these 5W-20 oils are only for fuel economy. If the EPA estimated fuel economy numbers don't change, then doesn't it follow that the manufacturer didn't get any additional CAFE credits? For example, in 2004, all the Chrysler minivan engines required 5w30. In 2005, they were all switched to 5W-20, but the EPA numbers remained the same. So what motivated Chrysler to re-print owner manuals and oil fill caps?
To the original poster, from what I've read, as the HT/HS goes up, engine wear goes down. But this general concept applies to most everything in life. The more you brush your teeth, the cleaner they are. I brush mine twice a day, and haven't had a cavity in all of my adult years. But some will give you a scolding for not brushing after every meal. In other words, even though additional "safeguards" can offer you additional levels of protection on paper or in theory, is that level of protection meaningful/measurable in your situation?
And certainly, HT/HS isn't the only factor. Modern 5W-20 oils have shown to be very shear-stable. Most folks don't realize that the 5w30 they have in their vehicles is likely sheared down to what would be considered a 5W-20 after a few thousand miles anyway.
In the end, I think it's mostly perception. If a 5w30 makes you feel better, use it. If you're questioning a 5W-20, run it for an OCI or two and get a UOA done.
ARCO, that statement in your manual may be particular to that particular engine design in your Yaris (what is it, the 1NZ-FE?), and may not apply to other situations.
I question the blanket speculation that these 5W-20 oils are only for fuel economy. If the EPA estimated fuel economy numbers don't change, then doesn't it follow that the manufacturer didn't get any additional CAFE credits? For example, in 2004, all the Chrysler minivan engines required 5w30. In 2005, they were all switched to 5W-20, but the EPA numbers remained the same. So what motivated Chrysler to re-print owner manuals and oil fill caps?
To the original poster, from what I've read, as the HT/HS goes up, engine wear goes down. But this general concept applies to most everything in life. The more you brush your teeth, the cleaner they are. I brush mine twice a day, and haven't had a cavity in all of my adult years. But some will give you a scolding for not brushing after every meal. In other words, even though additional "safeguards" can offer you additional levels of protection on paper or in theory, is that level of protection meaningful/measurable in your situation?
And certainly, HT/HS isn't the only factor. Modern 5W-20 oils have shown to be very shear-stable. Most folks don't realize that the 5w30 they have in their vehicles is likely sheared down to what would be considered a 5W-20 after a few thousand miles anyway.
In the end, I think it's mostly perception. If a 5w30 makes you feel better, use it. If you're questioning a 5W-20, run it for an OCI or two and get a UOA done.
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To the original poster, from what I've read, as the HT/HS goes up, engine wear goes down.
I wouldn't necessarily put it that way. The higher the HT/HS, the more it can endure stress. That doesn't mean that anyone needs or ever reaches those stress points in their operational variable. Most of the engines that spec 20 grades have engineered out those potential stressed states with either limiting power density higher refresh rate ..or however/whatever.
To the original poster, from what I've read, as the HT/HS goes up, engine wear goes down.
I wouldn't necessarily put it that way. The higher the HT/HS, the more it can endure stress. That doesn't mean that anyone needs or ever reaches those stress points in their operational variable. Most of the engines that spec 20 grades have engineered out those potential stressed states with either limiting power density higher refresh rate ..or however/whatever.
Originally Posted By: Gary Allan
Quote:
To the original poster, from what I've read, as the HT/HS goes up, engine wear goes down.
I wouldn't necessarily put it that way. The higher the HT/HS, the more it can endure stress. That doesn't mean that anyone needs or ever reaches those stress points in their operational variable. Most of the engines that spec 20 grades have engineered out those potential stressed states with either limiting power density higher refresh rate ..or however/whatever.
I've wondered how you thought about HTHS and it's protection in "normal" cars.
What I'm getting is that a low HTHS will protect the same as a high HTHS as long as the stress levels are kept under a certain level.
The reason I disagree with this is engines do wear out, even low power density engines driven easy. There still has to be occasional metal to whatever contact. This is why I believe a higher HTHS will still protect better even in a normal engine with normal driving. I'm sure the level of extra protection goes waaaaay down under normal service but I believe it is still there.
Quote:
To the original poster, from what I've read, as the HT/HS goes up, engine wear goes down.
I wouldn't necessarily put it that way. The higher the HT/HS, the more it can endure stress. That doesn't mean that anyone needs or ever reaches those stress points in their operational variable. Most of the engines that spec 20 grades have engineered out those potential stressed states with either limiting power density higher refresh rate ..or however/whatever.
I've wondered how you thought about HTHS and it's protection in "normal" cars.
What I'm getting is that a low HTHS will protect the same as a high HTHS as long as the stress levels are kept under a certain level.
The reason I disagree with this is engines do wear out, even low power density engines driven easy. There still has to be occasional metal to whatever contact. This is why I believe a higher HTHS will still protect better even in a normal engine with normal driving. I'm sure the level of extra protection goes waaaaay down under normal service but I believe it is still there.
Originally Posted By: Gary Allan
Quote:
To the original poster, from what I've read, as the HT/HS goes up, engine wear goes down.
I wouldn't necessarily put it that way. The higher the HT/HS, the more it can endure stress. That doesn't mean that anyone needs or ever reaches those stress points in their operational variable. Most of the engines that spec 20 grades have engineered out those potential stressed states with either limiting power density higher refresh rate ..or however/whatever.
I agree.
While HT/HS is an interesting oil spec' not everyone agrees upon its importance. In most racing applications where you would think it would be an important spec' it's not even measured.
In racing applications they simply deal with the operational viscosity as measured kinematically.
Take Red Line oil for example. Their street oils have one of the highest HT/HS spec' relative to their 100C k'vis of any motor oil, but they don't even bother to measure and provide a HT/HS spec' for their race oils.
When a mfr spec's a 20 wt oil, oil temperatures are invariably well contained. High oil temps are not expected to arise in all conditions under which the vehicle is designed to operate.
Quote:
To the original poster, from what I've read, as the HT/HS goes up, engine wear goes down.
I wouldn't necessarily put it that way. The higher the HT/HS, the more it can endure stress. That doesn't mean that anyone needs or ever reaches those stress points in their operational variable. Most of the engines that spec 20 grades have engineered out those potential stressed states with either limiting power density higher refresh rate ..or however/whatever.
I agree.
While HT/HS is an interesting oil spec' not everyone agrees upon its importance. In most racing applications where you would think it would be an important spec' it's not even measured.
In racing applications they simply deal with the operational viscosity as measured kinematically.
Take Red Line oil for example. Their street oils have one of the highest HT/HS spec' relative to their 100C k'vis of any motor oil, but they don't even bother to measure and provide a HT/HS spec' for their race oils.
When a mfr spec's a 20 wt oil, oil temperatures are invariably well contained. High oil temps are not expected to arise in all conditions under which the vehicle is designed to operate.
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Quote:
I've wondered how you thought about HTHS and it's protection in "normal" cars.
My reasoning is relatively simple ..and may indeed be flawed ..at least to some extent. There are engines that specify a given HT/HS. They all tend to be (something like) a Euro-Alloy. Those designs tend to be "complete" packages. That is, (at least from my perception/impression) when you buy a higher output Teutonic Technical Marvel, it's designed for full capability 24/7/365. It's not like your GN where you've only got about 15seconds of WOT before you're letting off the throttle. For you to upgrade your GN to TTM level, you would either have to double the sump and the cooling system ..or detune the engine to lower output. They don't do this. If you've got 150mph capability ...you can run the thing @ 150mph indefinitely aside from fuel stops.
In that type of design situation, you're always factoring for the most severe service ..to make it not severe at all. They "wrap around" the design goal ..which in this case is providing (for example) a 150mph car (more than that- but
).
Ford produced something like 757hp out of the SOHC 427 in the GT for Lemans (iirc). They had to detune it to 500hp to endure 24hours.
..are you catching my reasoned drift here? There has to be states where that HT/HS is nothing more than an unneeded "reserve" ..where it's a non-factor. Just like you could probably use a common 5w30 if you didn't have high spring rates ..and never entered your higher power production levels.
I've wondered how you thought about HTHS and it's protection in "normal" cars.
My reasoning is relatively simple ..and may indeed be flawed ..at least to some extent. There are engines that specify a given HT/HS. They all tend to be (something like) a Euro-Alloy. Those designs tend to be "complete" packages. That is, (at least from my perception/impression) when you buy a higher output Teutonic Technical Marvel, it's designed for full capability 24/7/365. It's not like your GN where you've only got about 15seconds of WOT before you're letting off the throttle. For you to upgrade your GN to TTM level, you would either have to double the sump and the cooling system ..or detune the engine to lower output. They don't do this. If you've got 150mph capability ...you can run the thing @ 150mph indefinitely aside from fuel stops.
In that type of design situation, you're always factoring for the most severe service ..to make it not severe at all. They "wrap around" the design goal ..which in this case is providing (for example) a 150mph car (more than that- but
Ford produced something like 757hp out of the SOHC 427 in the GT for Lemans (iirc). They had to detune it to 500hp to endure 24hours.
..are you catching my reasoned drift here? There has to be states where that HT/HS is nothing more than an unneeded "reserve" ..where it's a non-factor. Just like you could probably use a common 5w30 if you didn't have high spring rates ..and never entered your higher power production levels.
Originally Posted By: Gary Allan
Quote:
To the original poster, from what I've read, as the HT/HS goes up, engine wear goes down.
I wouldn't necessarily put it that way. The higher the HT/HS, the more it can endure stress. That doesn't mean that anyone needs or ever reaches those stress points in their operational variable. Most of the engines that spec 20 grades have engineered out those potential stressed states with either limiting power density higher refresh rate ..or however/whatever.
Thanks, that's a much better way to say what I was trying to say. I was trying to get there when I concluded, "In other words, even though additional "safeguards" can offer you additional levels of protection on paper or in theory, is that level of protection meaningful/measurable in your situation?"
Quote:
To the original poster, from what I've read, as the HT/HS goes up, engine wear goes down.
I wouldn't necessarily put it that way. The higher the HT/HS, the more it can endure stress. That doesn't mean that anyone needs or ever reaches those stress points in their operational variable. Most of the engines that spec 20 grades have engineered out those potential stressed states with either limiting power density higher refresh rate ..or however/whatever.
Thanks, that's a much better way to say what I was trying to say. I was trying to get there when I concluded, "In other words, even though additional "safeguards" can offer you additional levels of protection on paper or in theory, is that level of protection meaningful/measurable in your situation?"
you are surmising that there must be a small incidence of film breakdown or engines would never wear.
Not true - at least nto due to HTHS related film failure
They wear whenever they startup, and/or when run too fast when cold. Neither of these is affected by HTHS. In fact, w/r/t cold flow, they are generally inversely proportional. This is why oil is such a difficult topic - it has inherent trade-offs. They are not good nor bad - they must be selected for the application.
Grant
Not true - at least nto due to HTHS related film failure
They wear whenever they startup, and/or when run too fast when cold. Neither of these is affected by HTHS. In fact, w/r/t cold flow, they are generally inversely proportional. This is why oil is such a difficult topic - it has inherent trade-offs. They are not good nor bad - they must be selected for the application.
Grant
Too much theory and not enough practice sometimes here, I say.
Originally Posted By: Gary Allan
"... Euro-Alloy... higher output Teutonic Technical Marvel, it's designed for full capability 24/7/365"
That's funny Gary - After Epolk made me cry
, you made me laugh. Thank you, and dont forget that 10w-60 castrol in your "well engineered teutonic marvel", beemer guys ...
"... Euro-Alloy... higher output Teutonic Technical Marvel, it's designed for full capability 24/7/365"
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Originally Posted By: just_me
you are surmising that there must be a small incidence of film breakdown or engines would never wear.
Not true - at least nto due to HTHS related film failure
They wear whenever they startup, and/or when run too fast when cold. Neither of these is affected by HTHS. In fact, w/r/t cold flow, they are generally inversely proportional. This is why oil is such a difficult topic - it has inherent trade-offs. They are not good nor bad - they must be selected for the application.
Grant
That's great. So if an engine is started only once in it's life, it will run forever with 0 wear...
you are surmising that there must be a small incidence of film breakdown or engines would never wear.
Not true - at least nto due to HTHS related film failure
They wear whenever they startup, and/or when run too fast when cold. Neither of these is affected by HTHS. In fact, w/r/t cold flow, they are generally inversely proportional. This is why oil is such a difficult topic - it has inherent trade-offs. They are not good nor bad - they must be selected for the application.
Grant
That's great. So if an engine is started only once in it's life, it will run forever with 0 wear...
Originally Posted By: Eddie
And how did you find this out about you other driver ARCO?
What's that? the need for thicker oil for my Yaris or that my wife is the engine destroyer in the family?
And how did you find this out about you other driver ARCO?
What's that? the need for thicker oil for my Yaris or that my wife is the engine destroyer in the family?
Originally Posted By: Audi Junkie
Too much theory and not enough practice sometimes here, I say.
Not really. I post teardown results over several engines with the thinner lower HTHS engine wearing at 5x the rate and you guys always have some theory as to why it's not the oil. I get bombarded by worthless theories when I post real world results.
Too much theory and not enough practice sometimes here, I say.
Not really. I post teardown results over several engines with the thinner lower HTHS engine wearing at 5x the rate and you guys always have some theory as to why it's not the oil. I get bombarded by worthless theories when I post real world results.
Originally Posted By: BuickGN
Originally Posted By: Audi Junkie
Too much theory and not enough practice sometimes here, I say.
Not really. I post teardown results over several engines with the thinner lower HTHS engine wearing at 5x the rate and you guys always have some theory as to why it's not the oil. I get bombarded by worthless theories when I post real world results.
That's 5 data points on high performance engines! It's a nice anecdote.
If cars were wearing their engines out on 5w-20/5w30 at statistically higher rates compared to heavier grades, we'd know about it.
Others have also posted real world results of hundreds of thousands of miles using "thin" oils, but they had no reason to tear their motors down.
Originally Posted By: Audi Junkie
Too much theory and not enough practice sometimes here, I say.
Not really. I post teardown results over several engines with the thinner lower HTHS engine wearing at 5x the rate and you guys always have some theory as to why it's not the oil. I get bombarded by worthless theories when I post real world results.
That's 5 data points on high performance engines! It's a nice anecdote.
If cars were wearing their engines out on 5w-20/5w30 at statistically higher rates compared to heavier grades, we'd know about it.
Others have also posted real world results of hundreds of thousands of miles using "thin" oils, but they had no reason to tear their motors down.
For the most part HTHS is not much of a concern today for the average driver. Their was a time that the HTHS of the oil played a huge role in preventing wear especially to the rod bearing and 3.5hths was considered the norm for safe engine operation. Well a combination of tighter clearances. less tolerance stacking, and more durable tougher materials have all combined to make HTHS less of a player in the game of low engine wear! So if your vehicle specifications are in line with 5W20 or 0W20 as a growing number all then anything with an HTHS of 2.6-2.9 will more then likely get the job done. If you have an older engine then something more in line with the time period it was designed like 2.9-3.5 might be a better idea.
Back when I was a young mechanic 3.3 was my lower limit for HTHS but today I have seen my Camry do just as well on M1R0W30 which had an HTHS of around 2.9 if I recall as it did on Redline 5W40 which probablyhas an HTHS around 4.5-4.9...... The extra HTHS only does any good if you need it. So going with more then you need is only a good thing if you for see some type of extreme that would call for it as a "just in case" in the mean time most oils HTHS especialy those made of group I-III and PAO have a habit of needing to drasticly increase viscosity and drag to increase the HTHS significantly. Ester based fluids have much higher HTHS number then any other base stock for a given viscosity. THis is why Redlines 5W20 has a higher HTHS value then Mobil-1 5W30 or 10W30.
So start with OEM recommendations and then move up and down from their based on UOA. Most things are not universal for instance sometimes going to a thinner oil will reduce oil consumption more then going thicker will. While this is opposite common knowledge their are many counter intuitive things when it comes to oil for a car engine not everything is cut and dryy!
Back when I was a young mechanic 3.3 was my lower limit for HTHS but today I have seen my Camry do just as well on M1R0W30 which had an HTHS of around 2.9 if I recall as it did on Redline 5W40 which probablyhas an HTHS around 4.5-4.9...... The extra HTHS only does any good if you need it. So going with more then you need is only a good thing if you for see some type of extreme that would call for it as a "just in case" in the mean time most oils HTHS especialy those made of group I-III and PAO have a habit of needing to drasticly increase viscosity and drag to increase the HTHS significantly. Ester based fluids have much higher HTHS number then any other base stock for a given viscosity. THis is why Redlines 5W20 has a higher HTHS value then Mobil-1 5W30 or 10W30.
So start with OEM recommendations and then move up and down from their based on UOA. Most things are not universal for instance sometimes going to a thinner oil will reduce oil consumption more then going thicker will. While this is opposite common knowledge their are many counter intuitive things when it comes to oil for a car engine not everything is cut and dryy!
THe easiest way to think about HTHS is image you are shoping for a mattress. You want to put the mattress over bottles of nitro glyserine because kids keep chucking cinder blocks off the over pass and you do not want your nitro to go off.
The higher the HTHS the thicker the mattress is between that falling cider block and you bottles of active nitro in the bed of the truck. Now it might be that you can mathmaticly workout that a mattress of 4 inch's made from X type of closed cell foam will stop a cinder block tossed off the overpass at a hiegiht of 14 feet 8 inch's in a truck moveing at 70MPH. But what happens when two cinder blocks hit at the same time in the same place you see my point then the minimum just failed you and you and your truck and the 8 lanes of trafic are all now gone and their is a 22 foot deep crater where you used to be.
So really you have to take into acount the fuel milage loss if any for the added protection? How likely are you to need it? Now if you want more protection and do not want to pay for it in fuel ecconomy then you have only one choice you need to switch to an oil that is made up mostly of ester base stocks like Redline,Motul 300V, Neo etc.....
The higher the HTHS the thicker the mattress is between that falling cider block and you bottles of active nitro in the bed of the truck. Now it might be that you can mathmaticly workout that a mattress of 4 inch's made from X type of closed cell foam will stop a cinder block tossed off the overpass at a hiegiht of 14 feet 8 inch's in a truck moveing at 70MPH. But what happens when two cinder blocks hit at the same time in the same place you see my point then the minimum just failed you and you and your truck and the 8 lanes of trafic are all now gone and their is a 22 foot deep crater where you used to be.
So really you have to take into acount the fuel milage loss if any for the added protection? How likely are you to need it? Now if you want more protection and do not want to pay for it in fuel ecconomy then you have only one choice you need to switch to an oil that is made up mostly of ester base stocks like Redline,Motul 300V, Neo etc.....
Originally Posted By: BuickGN
Originally Posted By: Audi Junkie
Too much theory and not enough practice sometimes here, I say.
Not really. I post teardown results over several engines with the thinner lower HTHS engine wearing at 5x the rate and you guys always have some theory as to why it's not the oil. I get bombarded by worthless theories when I post real world results.
I have 19 years of cold starts and 300,000+ miles on my still hard working Toyota with 4.5 HTHS oil. 11 years of more than one cold start per day and 214,000+ miles on my Cavalier. My son in law has either a 2007 or 2008(he bought it in like September of 2007 so I don't remember which) Chrysler V6 engine van which runs in city traffic in DC, Arlington, Fairfax, and Manassas, runs to Orlando, Hally, Conn., Middlesboro, KY, 2-3 times a month, and now has 14X,000, 4.5 HTHS trouble free miles on it. It replaced another Chrysler van, which replaced a Ford van. He averages about 76,000 miles a year.
I am convinced beyond any doubt that life starts with a 100C cSt of at least 12.5, an HTHS of at least 3.5, and gets better up the line.
Gary said it is margins, and I believe he is exactly correct. I have my two trucks and car engines(and transmissions) protected from situations and circumstances they will likely never see/experience. If I found an oil that I really believed would give me like 1% more protection than what I now use, I would change out tomorrow.
When I bought my 1986 Toyota truck I assumed I would not need another truck for 200,000, and I would have those 200,000 miles trouble free service. I now have like 301,327 miles. When I bought my wife's 1999 Cavalier, I assumed I would not need to look at another car for 200,000 miles. It now has 214,000+ miles. When her Cavalier reached 200,000 miles, my wife reminded me that she got a new vehicle. She wanted a full size pickup with a camper pac so I bought a 2008 Silverado pickup. I assumed 250,000 miles trouble free from engine or transmission. It gets like 8,000 miles a year so I expect it to be around for a very long time.
Gary, I agree with all you say about margins. But, you know the type of nut case that I am.
I have hunted whitetail deer and feral hogs since 1958. As I got older with more serious medical problems, I have had to go to a much smaller, lighter rifle. I had Silas Silkiss build me a 458 Barnes magnum.
Originally Posted By: Audi Junkie
Too much theory and not enough practice sometimes here, I say.
Not really. I post teardown results over several engines with the thinner lower HTHS engine wearing at 5x the rate and you guys always have some theory as to why it's not the oil. I get bombarded by worthless theories when I post real world results.
I have 19 years of cold starts and 300,000+ miles on my still hard working Toyota with 4.5 HTHS oil. 11 years of more than one cold start per day and 214,000+ miles on my Cavalier. My son in law has either a 2007 or 2008(he bought it in like September of 2007 so I don't remember which) Chrysler V6 engine van which runs in city traffic in DC, Arlington, Fairfax, and Manassas, runs to Orlando, Hally, Conn., Middlesboro, KY, 2-3 times a month, and now has 14X,000, 4.5 HTHS trouble free miles on it. It replaced another Chrysler van, which replaced a Ford van. He averages about 76,000 miles a year.
I am convinced beyond any doubt that life starts with a 100C cSt of at least 12.5, an HTHS of at least 3.5, and gets better up the line.
Gary said it is margins, and I believe he is exactly correct. I have my two trucks and car engines(and transmissions) protected from situations and circumstances they will likely never see/experience. If I found an oil that I really believed would give me like 1% more protection than what I now use, I would change out tomorrow.
When I bought my 1986 Toyota truck I assumed I would not need another truck for 200,000, and I would have those 200,000 miles trouble free service. I now have like 301,327 miles. When I bought my wife's 1999 Cavalier, I assumed I would not need to look at another car for 200,000 miles. It now has 214,000+ miles. When her Cavalier reached 200,000 miles, my wife reminded me that she got a new vehicle. She wanted a full size pickup with a camper pac so I bought a 2008 Silverado pickup. I assumed 250,000 miles trouble free from engine or transmission. It gets like 8,000 miles a year so I expect it to be around for a very long time.
Gary, I agree with all you say about margins. But, you know the type of nut case that I am.
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