Re: It is not how far you drive per day but how hot the engine gets during that drive... |  |  |
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| Oil talk Jim in Iowa - Sunday, 6 October, 2013, at 4:22:58 pm |
I had a question on a recent oil test report, so I called the lab. As long as I had the lab tech on the phone, I asked a bunch of general questions that I'd been pondering.
There may be no area in the automotive world as varied as oil advice. Porsche AG has a list of approved oils. In the U.S., most dealers and owners use Mobil 1, and it's factory fill. Some people think this list is a good guide, others call it (or Mobil, in particular) a marketing scheme.
The PCA's tech editor Alan Caldwell (a retired Boeing engineer) did an extensive look at oils, and concluded that so long as the oil is Porsche-approved, and the second number in the formulation is 40 or higher, change at factory intervals, and you are good to go.
Excellence magazine's tech staff recommends using Motul, often with much more frequent than the factory recommended change intervals. You'll see a bunch of other places recommend changing oil every 3K miles.
One really interesting question I saw posed at the 2009 Mobil 1 Parade tech session, during the 9x7 generation of cars, Porsche shortened the drain interval. I forget the exact number, but maybe it went from 15K down to 12K, something like that. Someone in the audience asked was that interval change due to the high frequency of ethanol in most U.S. gasoline, and as the alcohol is a solvent, does it strip the lubrication from the cylinder walls faster and break the oil down more quickly? Nobody answered that question, unfortunately.
Then of course there is the lowering of the ZDDP levels in oil in the last few years, a source of great consternation.
To paraphrase Mobil's position, they told us that there are only two mass producers of the synthetic oil base stock in the world, Exxon-Mobil was one, and I forget the other, it might have been Royal Dutch Shell. So all of the various boutique oils are using one of the major's base stock, and putting in their own additive package.
As to the ZDDP drop, Mobil says that's due to the EPA getting after the SAE (Society of Automotive Engineers), who do the oil certification. The EPA wants more life out of catalytic converters, I want to say a certain amount of effectiveness at 10 years instead of 8. The zinc and phosphorus metals build-up inside the cat, reducing its effectiveness over time.
Mobil says that ZDDP is a very cost-effective anti-wear additive, hence its widespread use. It's a relatively old additive, dating back to the late 1940s. They note that it's not the *only* anti-wear additive in the oil formulation array, nor is it magic, there are others, but they are generally newer and more expensive. ZDDP was popular because it works, and is low oost.
The engines reportedly most prone to wear issues are those with "flat tappet' engines, such as the original Beetle. Mobil said that no Porsche motor from the 911 (1964) onward has that flat tappet condition (not sure on 356s).
Some users have become fixated on reduced levels of ZDDP as being the potiential cause for many ills. Hemming's, the classic car car magazine, even markets a self-branded oil with high levels of ZDDP, "to protect your engine."
Mobil, being aware of this stumbling block, has their "Racing" line of Mobil 1, so anyone insistent upon high ZDDP levels can get it. The EPA generally won't concern themselves with a "racing' labeled product, as they assume that's for off-road use, or small potatoes on road.
So that brings me to the lab again. When I asked what levels of increased wear were they seeing with these newer low ZDDP oils, the answer is "None." They base their judgment of how an oil is doing upon the wear metals coming out of the engine, and the measured characteristics of the oil. So it's interesting to see that wear metals are no different with lower ZDDP.
Moreover, the flat tappet engines that have people so worried about wear, they're not showing up with any elevation in wear metals, either. When I asked for possible reasons why, he said they were using other anti-wear agents to replace the ZDDP, most often molybendum.
My next question was how do the various Porsche-approved synthetic oils do in their wear metals profile? Is Motul or Shell Helix, for example, better than Mobil 1? He said their lab hasn't seen any significant differences, they all do a fairly equal, excellent job. It's also interesting to note that the unit location averages in your oil report are for your type of engine, not all engines. So if you've got a 3.2L M96, they'll show you averages for other 3.2L M96s. I asked how big the population was for that group, and he said around 200 motors.
I then asked about interval changes. He said that during warranty, it's important to always follow the manufacturer's guidance. He added that 95% of the oil samples that they receive *didn't *need to have their oil changed. The oil was not worn out, nor was there too many wear particles in it. So much for the 3,000 mile oil change myth vs. data.
I asked what about time? Should engines always have their oil changed in selected time? That's usually once a year for Porsche. He said in warranty, always follow the rules. Out of warranty, mileage is more important. For automotive engines, they're so "tight' when it comes to environmental exposure (per the EPA), you don't have to worry about time so much. Now for piston-driven aviation engines, time is far more important because they're not as tightly sealed.
I said hypothetically speaking, if you bought a new Porsche, would you change the oil early, or wait for the full year or 12K miles? He said he'd be tempted to change maybe before a winter storage to get the wear metals out, but you probably don't need to do it. He said most German engines these days don't throw off much in the way of wear metals, anyway.
So it sounds as though Alan Caldwell's advice really is a safe way to go without overthinking it.
Thought you'd all be interested.
There may be no area in the automotive world as varied as oil advice. Porsche AG has a list of approved oils. In the U.S., most dealers and owners use Mobil 1, and it's factory fill. Some people think this list is a good guide, others call it (or Mobil, in particular) a marketing scheme.
The PCA's tech editor Alan Caldwell (a retired Boeing engineer) did an extensive look at oils, and concluded that so long as the oil is Porsche-approved, and the second number in the formulation is 40 or higher, change at factory intervals, and you are good to go.
Excellence magazine's tech staff recommends using Motul, often with much more frequent than the factory recommended change intervals. You'll see a bunch of other places recommend changing oil every 3K miles.
One really interesting question I saw posed at the 2009 Mobil 1 Parade tech session, during the 9x7 generation of cars, Porsche shortened the drain interval. I forget the exact number, but maybe it went from 15K down to 12K, something like that. Someone in the audience asked was that interval change due to the high frequency of ethanol in most U.S. gasoline, and as the alcohol is a solvent, does it strip the lubrication from the cylinder walls faster and break the oil down more quickly? Nobody answered that question, unfortunately.
Then of course there is the lowering of the ZDDP levels in oil in the last few years, a source of great consternation.
To paraphrase Mobil's position, they told us that there are only two mass producers of the synthetic oil base stock in the world, Exxon-Mobil was one, and I forget the other, it might have been Royal Dutch Shell. So all of the various boutique oils are using one of the major's base stock, and putting in their own additive package.
As to the ZDDP drop, Mobil says that's due to the EPA getting after the SAE (Society of Automotive Engineers), who do the oil certification. The EPA wants more life out of catalytic converters, I want to say a certain amount of effectiveness at 10 years instead of 8. The zinc and phosphorus metals build-up inside the cat, reducing its effectiveness over time.
Mobil says that ZDDP is a very cost-effective anti-wear additive, hence its widespread use. It's a relatively old additive, dating back to the late 1940s. They note that it's not the *only* anti-wear additive in the oil formulation array, nor is it magic, there are others, but they are generally newer and more expensive. ZDDP was popular because it works, and is low oost.
The engines reportedly most prone to wear issues are those with "flat tappet' engines, such as the original Beetle. Mobil said that no Porsche motor from the 911 (1964) onward has that flat tappet condition (not sure on 356s).
Some users have become fixated on reduced levels of ZDDP as being the potiential cause for many ills. Hemming's, the classic car car magazine, even markets a self-branded oil with high levels of ZDDP, "to protect your engine."
Mobil, being aware of this stumbling block, has their "Racing" line of Mobil 1, so anyone insistent upon high ZDDP levels can get it. The EPA generally won't concern themselves with a "racing' labeled product, as they assume that's for off-road use, or small potatoes on road.
So that brings me to the lab again. When I asked what levels of increased wear were they seeing with these newer low ZDDP oils, the answer is "None." They base their judgment of how an oil is doing upon the wear metals coming out of the engine, and the measured characteristics of the oil. So it's interesting to see that wear metals are no different with lower ZDDP.
Moreover, the flat tappet engines that have people so worried about wear, they're not showing up with any elevation in wear metals, either. When I asked for possible reasons why, he said they were using other anti-wear agents to replace the ZDDP, most often molybendum.
My next question was how do the various Porsche-approved synthetic oils do in their wear metals profile? Is Motul or Shell Helix, for example, better than Mobil 1? He said their lab hasn't seen any significant differences, they all do a fairly equal, excellent job. It's also interesting to note that the unit location averages in your oil report are for your type of engine, not all engines. So if you've got a 3.2L M96, they'll show you averages for other 3.2L M96s. I asked how big the population was for that group, and he said around 200 motors.
I then asked about interval changes. He said that during warranty, it's important to always follow the manufacturer's guidance. He added that 95% of the oil samples that they receive *didn't *need to have their oil changed. The oil was not worn out, nor was there too many wear particles in it. So much for the 3,000 mile oil change myth vs. data.
I asked what about time? Should engines always have their oil changed in selected time? That's usually once a year for Porsche. He said in warranty, always follow the rules. Out of warranty, mileage is more important. For automotive engines, they're so "tight' when it comes to environmental exposure (per the EPA), you don't have to worry about time so much. Now for piston-driven aviation engines, time is far more important because they're not as tightly sealed.
I said hypothetically speaking, if you bought a new Porsche, would you change the oil early, or wait for the full year or 12K miles? He said he'd be tempted to change maybe before a winter storage to get the wear metals out, but you probably don't need to do it. He said most German engines these days don't throw off much in the way of wear metals, anyway.
So it sounds as though Alan Caldwell's advice really is a safe way to go without overthinking it.
Thought you'd all be interested.
Laz - Sunday, 6 October, 2013, at 5:37:53 pm |
It might be the same for 987s and/or the latest oil change interval: every 10k but no later than every 12 months. My Honda gets its dino oil changed at 3k, but for a street Porsche motor on full synthetic, that is way too excessive. I might settle into 7500 miles for my 981. You've likely initiated a very long, and contentious thread!
| Re: Terrific writeup +1 Guenter in Ontario - Sunday, 6 October, 2013, at 7:07:32 pm |
| High levels of ZDDP can actually cause wear. The ZDDP under heat/pressure reacts... MarcW - Sunday, 6 October, 2013, at 8:59:40 pm |
with the metal it is supposed to protect, attacking the grain boundaries. The metal surface suffers from spalling and there you go. Worn out cam shaft lobe or a lifter bucket.
The Porsche engines with their light valve hardware and low spring pressure do not require the extra ZDDP that OHV engines require with their high lift cams, heavy valve hardware (remember: Lifter, push rod, rocker arm) and resulting high spring pressures to control the valves at high RPM.
An early oil change is not necessarily to get the wear metals out (although the amount of metal in the factory fill oil that came out of my Cayman S engine was enough to convince me my decision to change the oil early was the right one) but to drain the oil that is contaminated with unburned fuel and water and other byproducts of combustion. The fuel and water dilute the oil and render it less effective at protecting bearing surfaces under high pressure/high temperature usage.
Also, the other contaminates combine with the water to form acid compounds and leaving the engine sit over the winter with this acidic oil is borderline abuse imho.
The Porsche engines with their light valve hardware and low spring pressure do not require the extra ZDDP that OHV engines require with their high lift cams, heavy valve hardware (remember: Lifter, push rod, rocker arm) and resulting high spring pressures to control the valves at high RPM.
An early oil change is not necessarily to get the wear metals out (although the amount of metal in the factory fill oil that came out of my Cayman S engine was enough to convince me my decision to change the oil early was the right one) but to drain the oil that is contaminated with unburned fuel and water and other byproducts of combustion. The fuel and water dilute the oil and render it less effective at protecting bearing surfaces under high pressure/high temperature usage.
Also, the other contaminates combine with the water to form acid compounds and leaving the engine sit over the winter with this acidic oil is borderline abuse imho.
| Another reason to change the oil, or at least the filter Roger987 - Sunday, 6 October, 2013, at 9:21:56 pm |
| Have you ever seen evidence of spalling from ZDDP in the real-world? First hand? Papers? grant - Monday, 7 October, 2013, at 2:34:42 pm |
i frankly think its noise. But i dont really know.
I assume that the reaction against ZDDP is specifically abotu fouling cats. And, honestly, if you dont burn oil i have no idea how the ZDDP gets through the exhaust and into the cats. So i completely ignore it.
Always ready to learn though!
Grant
Grant
gee-lenahan-at-gee-mail-dot-com
I assume that the reaction against ZDDP is specifically abotu fouling cats. And, honestly, if you dont burn oil i have no idea how the ZDDP gets through the exhaust and into the cats. So i completely ignore it.
Always ready to learn though!
Grant
Grant
gee-lenahan-at-gee-mail-dot-com
| GM supposedly is the company that looked into this. Here's a link... MarcW - Monday, 7 October, 2013, at 4:35:12 pm |
| I'll follow that link, thanks. Still sounds like noise in the system at first glance. *NM* grant - Tuesday, 8 October, 2013, at 7:29:09 pm |
| Eeek! MArc, you didn't mention that they were talking about over 0.2% - that's like 10-20x grant - Tuesday, 8 October, 2013, at 7:34:54 pm |
.. most current levels. Typically people are looking for 0.05 - 0.1% ZDDP for older cars and to protect in barrier lubrication mode (which is never discussed by these articles that set up a straw-man that they can knock down). That's highly misleading on TWO counts.
True, but much in the same vein that water is poisonous to us all. it is, if you consume enough. really.
Grant
Grant
gee-lenahan-at-gee-mail-dot-com
True, but much in the same vein that water is poisonous to us all. it is, if you consume enough. really.
Grant
Grant
gee-lenahan-at-gee-mail-dot-com
| Non gas oil additives are listed by weight. For instance the amount of ZDDP in 15w-50... MarcW - Wednesday, 9 October, 2013, at 10:04:48 am |
| Thanks for posting Roger987 - Sunday, 6 October, 2013, at 9:08:01 pm |
| Re: Thanks for posting Ed B - Monday, 7 October, 2013, at 9:27:14 am |
Good info.
Unless you are flooding the engine, the amount of ethanol getting by the rings is negligible. The real problem is stop and go driving where the engine never gets completely warm to evaporate crankcase condensation.
My flat tappet engines use Brad Penn oil with high ZDDP. My 2000 Boxster S and 944T have Mobil 1 15-50. The Audis have Mobil 1 0-40 and 5-40.
The 2004 GT3 had its oil changed at 3000 miles by the previous owner to TOTAL 5-40 and again at 10000 miles by me. I'm impressed with TOTAL. In an unscientific test, the TOTAL retained its viscosity much better than the Mobil 1. I think that Mobil 1's reduced viscosity has been reported else ware.
Oil doesn't wear out, the additives do and contaminants will build up. How often you change oil depends on how the car is used. I think I'll be changing from Mobil 1 to TOTAL.
I usually change oil and filter about every 5000 miles.
Ed B
Unless you are flooding the engine, the amount of ethanol getting by the rings is negligible. The real problem is stop and go driving where the engine never gets completely warm to evaporate crankcase condensation.
My flat tappet engines use Brad Penn oil with high ZDDP. My 2000 Boxster S and 944T have Mobil 1 15-50. The Audis have Mobil 1 0-40 and 5-40.
The 2004 GT3 had its oil changed at 3000 miles by the previous owner to TOTAL 5-40 and again at 10000 miles by me. I'm impressed with TOTAL. In an unscientific test, the TOTAL retained its viscosity much better than the Mobil 1. I think that Mobil 1's reduced viscosity has been reported else ware.
Oil doesn't wear out, the additives do and contaminants will build up. How often you change oil depends on how the car is used. I think I'll be changing from Mobil 1 to TOTAL.
I usually change oil and filter about every 5000 miles.
Ed B
| Re: Oil talk gedwin - Monday, 7 October, 2013, at 9:43:45 am |
"I then asked about interval changes. He said that during warranty, it's important to always follow the manufacturer's guidance. He added that 95% of the oil samples that they receive *didn't *need to have their oil changed. The oil was not worn out, nor was there too many wear particles in it. So much for the 3,000 mile oil change myth vs. data."
This is interesting. I still wish I could get a better answer regarding whether I am wasting my time changing my strictly street driven 981's oil at 5K when the interval calls for 10K. I drive far enough every day to burn off condensation, and don't mind changing more often if the engine needs it. I just don't like wasting time, money, and oil if it is not needed.
The quote above tells us to follow the manufacturers guidance, but that is a minimum, and we know that. It states that 95% of samples didn't need changing, but we don't anything about those samples (miles, usage, etc.).
This is interesting. I still wish I could get a better answer regarding whether I am wasting my time changing my strictly street driven 981's oil at 5K when the interval calls for 10K. I drive far enough every day to burn off condensation, and don't mind changing more often if the engine needs it. I just don't like wasting time, money, and oil if it is not needed.
The quote above tells us to follow the manufacturers guidance, but that is a minimum, and we know that. It states that 95% of samples didn't need changing, but we don't anything about those samples (miles, usage, etc.).
| It is not how far you drive per day but how hot the engine gets during that drive... MarcW - Monday, 7 October, 2013, at 10:07:38 am |
Quote
gedwin
"I then asked about interval changes. He said that during warranty, it's important to always follow the manufacturer's guidance. He added that 95% of the oil samples that they receive *didn't *need to have their oil changed. The oil was not worn out, nor was there too many wear particles in it. So much for the 3,000 mile oil change myth vs. data."
This is interesting. I still wish I could get a better answer regarding whether I am wasting my time changing my strictly street driven 981's oil at 5K when the interval calls for 10K. I drive far enough every day to burn off condensation, and don't mind changing more often if the engine needs it. I just don't like wasting time, money, and oil if it is not needed.
The quote above tells us to follow the manufacturers guidance, but that is a minimum, and we know that. It states that 95% of samples didn't need changing, but we don't anything about those samples (miles, usage, etc.).
At first with my new Boxster I was driving around 20 miles (round trip) for work every day. I was making 60 to 80 mile round trip drives from where I lived 20 miles east of the KC MO metro area all the way to the other side of the KC MO metro area. Then once or twice a week I was driving 150 miles to see my parents.
The trouble is this was in the dead of winter and the engine just didn't that hot. So on a whim when I had the Boxster's oil analyzed and found 7% water content after just 4K miles of driving, that's when I realized how cold these engines could run in winter conditions and that's when I decided no way I was adhering to the 15K miles oil (and 30K miles filter) service schedule.
I decided upon 5K miles.
Now about this time (March of 2002) I bought a new VW Golf TDi to use as my "winter" car. I forget now what miles VW had for the car's oil/filter service interval but there was a notice over the SM desk that VW had declared the region a severe usage region due to I guess ambient temperature, humid, traffic (traffic was horrible there though for the most part I managed to avoid driving in the worst of it), and dust in the air. Because of this VW had cut in half the recommended oil/filter service interval. I noted that the VW dealer was just across the freeway from the Porsche dealer.
To get my Boxster's engine hot enough radiator fans come on and they come on low speed when the coolant reaches 212F requires more than just driving some distance even on warm days. And if it is warm enough (or cold enough) to require I turn on the auto climate system and run the A/C forget it. The radiator fans run all the time and this keeps the engine coolant temperature quite a bit below that 212F threshold. To get the fans to come on requires no A/C (for either cooling on a hot day or heating on a cold day) and some real slow driving, like around a parking lot. I might mention the 996 is even worse, that is harder to get hot. Its aerodynamics are so good that even moving at a rather slow pace has enough air flowing through the radiators that it can take minutes of driving at slow speeds and idling before the fans come on.
| Re: It is not how far you drive per day but how hot the engine gets during that drive... gedwin - Monday, 7 October, 2013, at 1:55:27 pm |
Quote
MarcW
At first with my new Boxster I was driving around 20 miles (round trip) for work every day. I was making 60 to 80 mile round trip drives from where I lived 20 miles east of the KC MO metro area all the way to the other side of the KC MO metro area. Then once or twice a week I was driving 150 miles to see my parents.
The trouble is this was in the dead of winter and the engine just didn't that hot. So on a whim when I had the Boxster's oil analyzed and found 7% water content after just 4K miles of driving, that's when I realized how cold these engines could run in winter conditions and that's when I decided no way I was adhering to the 15K miles oil (and 30K miles filter) service schedule.
I decided upon 5K miles.
Now about this time (March of 2002) I bought a new VW Golf TDi to use as my "winter" car. I forget now what miles VW had for the car's oil/filter service interval but there was a notice over the SM desk that VW had declared the region a severe usage region due to I guess ambient temperature, humid, traffic (traffic was horrible there though for the most part I managed to avoid driving in the worst of it), and dust in the air. Because of this VW had cut in half the recommended oil/filter service interval. I noted that the VW dealer was just across the freeway from the Porsche dealer.
To get my Boxster's engine hot enough radiator fans come on and they come on low speed when the coolant reaches 212F requires more than just driving some distance even on warm days. And if it is warm enough (or cold enough) to require I turn on the auto climate system and run the A/C forget it. The radiator fans run all the time and this keeps the engine coolant temperature quite a bit below that 212F threshold. To get the fans to come on requires no A/C (for either cooling on a hot day or heating on a cold day) and some real slow driving, like around a parking lot. I might mention the 996 is even worse, that is harder to get hot. Its aerodynamics are so good that even moving at a rather slow pace has enough air flowing through the radiators that it can take minutes of driving at slow speeds and idling before the fans come on.[/quote]
Thanks Marc. I'm reaching full oil and coolant temp each time I drive it, and driving for about 45 minutes after that. That's both summer and winter, year round, every day, twice a day. So I think I should be clearing out the water content. If not, then it would seem most people would have it worse than me, and Porsche would recommend shorter intervals based on that. But who really knows.
Also, I don't believe that you need to see 212F to remove the water, IF you drive long enough. Water can steam off without boiling, just takes longer. At least this is my experience with many other vehicles.
I guess I can answer my own question by putting 10K on the oil, then send it out for analysis. Then I would know for sure.
| I used to put cardboard on my radiator in the winter. After reading that, i may again! *NM* grant - Thursday, 10 October, 2013, at 8:18:39 pm |
| Yea, its that "area under the curve" bit - it comes down to grant - Monday, 7 October, 2013, at 2:31:48 pm |
..boiling off water
.. boiling off lighter acids (some dont boil off)
.. circulating sufficient hot, detergent oil to carry away lots of stuff that otherwise sits, adheres, gums, etc
So its some mysterious combination of hot and time.
I wish i knew the specifics, btu i deal with "hot" and "for a while"
Grant
Grant
gee-lenahan-at-gee-mail-dot-com
.. boiling off lighter acids (some dont boil off)
.. circulating sufficient hot, detergent oil to carry away lots of stuff that otherwise sits, adheres, gums, etc
So its some mysterious combination of hot and time.
I wish i knew the specifics, btu i deal with "hot" and "for a while"
Grant
Grant
gee-lenahan-at-gee-mail-dot-com
| Why is my used oil black? Bruce In Philly (2000 S Boxster, now '09 C2S) - Monday, 7 October, 2013, at 2:12:26 pm |
| those are detergents doing their job.... grant - Monday, 7 October, 2013, at 2:27:46 pm |
| Hoo boy - lots of good advice here - but also lots of "except that..." grant - Monday, 7 October, 2013, at 2:25:34 pm |
I dont have timeo go through this line by line, but there are a bunch of subtle points being lost.
I recently arranged for one of the lead formulation guys from BP lubricants (aka Castrol, BP) in to speak to NNJR-PCA. Note that BP makes its own base stock adn holds some of the patents. Part of what he did was dissect A40 and ask "why?".
I have input from a number of labs that I have shared. I cannto share the source. Note that some A40 oils had a darn hard time passing A40 and ACEA A3/B4.
Much of thsi note is good - to a point. But certain comments worry me - such as "so long as the higher number is 40 or above" - ignores the very important contribution of the SPREAD (e.g.: 40-5 = 35) to shear stability - the higher number otherwise falls over time folks. Actualyl its the ratio of the spread to the base number. On the street none of it really matters, to be honest.
etc.
I'll get to it.
Grant
Grant
gee-lenahan-at-gee-mail-dot-com
Edited 1 time(s). Last edit at 10/07/2013 02:52PM by grant. (view changes)
I recently arranged for one of the lead formulation guys from BP lubricants (aka Castrol, BP) in to speak to NNJR-PCA. Note that BP makes its own base stock adn holds some of the patents. Part of what he did was dissect A40 and ask "why?".
I have input from a number of labs that I have shared. I cannto share the source. Note that some A40 oils had a darn hard time passing A40 and ACEA A3/B4.
Much of thsi note is good - to a point. But certain comments worry me - such as "so long as the higher number is 40 or above" - ignores the very important contribution of the SPREAD (e.g.: 40-5 = 35) to shear stability - the higher number otherwise falls over time folks. Actualyl its the ratio of the spread to the base number. On the street none of it really matters, to be honest.
etc.
I'll get to it.
Grant
Grant
gee-lenahan-at-gee-mail-dot-com
Edited 1 time(s). Last edit at 10/07/2013 02:52PM by grant. (view changes)
Laz - Monday, 7 October, 2013, at 4:31:24 pm |
| It would not be appropriate to say that, either way, no, but i can say that grant - Monday, 7 October, 2013, at 9:29:48 pm |
| Based on what oils Porsche approves all of its approved oils have an upper limjit of viscosity... MarcW - Monday, 7 October, 2013, at 4:44:45 pm |
between 40 and 50.
You keep bringing the spread between the W viscosity and the high temp viscosity. Porsche doesn't apparently feel the spread is an issue for it approves not one 10w-XX or 15w-XX or 20w-XX oil for its sports cars manufactured since circa 1985.
As for having trouble passing the "ACEA A3/B4" test specs I wonder how much these matter any more? I note Porsche doesn't approve all oils that meet these so the fact that the oils do meet this is not enough to warrant approving the oil. My thinking is likewise while some approved oils may have a trouble passing the ACEA A3/B4 tests so what? The oils meet with Porsche's approval which may not line up exactly with what is required to pass ACEA A3/B4 tests with top marks.
'course if you do not give Porsche and its approved oils list any weight (no pun intended) then the whole oil world is open to you and you can select any oil based on any criteria you want. If the spread between 0w-40 scares you, then run 10w-40. What does it matter? You've elected to go off the Porsche oils reservation so you are on your own. You can justify your decision any way you want.
You keep bringing the spread between the W viscosity and the high temp viscosity. Porsche doesn't apparently feel the spread is an issue for it approves not one 10w-XX or 15w-XX or 20w-XX oil for its sports cars manufactured since circa 1985.
As for having trouble passing the "ACEA A3/B4" test specs I wonder how much these matter any more? I note Porsche doesn't approve all oils that meet these so the fact that the oils do meet this is not enough to warrant approving the oil. My thinking is likewise while some approved oils may have a trouble passing the ACEA A3/B4 tests so what? The oils meet with Porsche's approval which may not line up exactly with what is required to pass ACEA A3/B4 tests with top marks.
'course if you do not give Porsche and its approved oils list any weight (no pun intended) then the whole oil world is open to you and you can select any oil based on any criteria you want. If the spread between 0w-40 scares you, then run 10w-40. What does it matter? You've elected to go off the Porsche oils reservation so you are on your own. You can justify your decision any way you want.
| Yea, i keep bringing it up because... grant - Tuesday, 8 October, 2013, at 8:19:34 am |
If you care about extreme performance at high heat, pressure and rpms, its about as important as it gets. A base stock that flows per the API5 template simply cannot have the smae film strength at 100 degC and 6000 rpm as one with a base stock that flows per the API20 template. They either a) fall short; b) take VIIs or more VIIs or c) both. Not negotiable, all other things equal.
And remember that when they shear at high temperature, not only do you lose the upper range protection (e.g.: it becomes a xw30) but the by-products form sludge. Goodie.
If you drive sedately, even with some spirit on the street, very little of this matters except changing oil when it gets old, acid, diluted etc.
Porsche's motivations are not the same as many of ours. And some of us - those who should really worry - are using the cars under more extreme circumstances.
For the rest of the world, i'm sure that relatively fresh 5w30 is fine. Just don't expect it to protect at 100+ deg C and hgih rpms. Which, on my morning commute occurs roughly, well, never.
Porsche has indeed approved lots of ranges of oils. You take what you can get - and they all will meet the specs. But make no mistake, all other things equal, a 20w40 will outperform a 5w40 at hgih temperature, but flow more poorly in the cold. For most "appliance" owners, this is likely NOT a good trade-off, but for me at the track or mixed track/street use ( and using my brain) - it IS a good thing.
That's the big point. There are few"good" or "bad" oils. There are oils with different characteristics, and we need to pick them knowing how they will be used, or, conversely, modify our use to suit them.
Similarly there are a few things that are simply "better". Oils with hgih TBNs will counteract acids longer (duh). Changing oils maintains its additive package, avoids shear, and discards accumulated acids and water.
Grant
Grant
gee-lenahan-at-gee-mail-dot-com
And remember that when they shear at high temperature, not only do you lose the upper range protection (e.g.: it becomes a xw30) but the by-products form sludge. Goodie.
If you drive sedately, even with some spirit on the street, very little of this matters except changing oil when it gets old, acid, diluted etc.
Porsche's motivations are not the same as many of ours. And some of us - those who should really worry - are using the cars under more extreme circumstances.
For the rest of the world, i'm sure that relatively fresh 5w30 is fine. Just don't expect it to protect at 100+ deg C and hgih rpms. Which, on my morning commute occurs roughly, well, never.
Porsche has indeed approved lots of ranges of oils. You take what you can get - and they all will meet the specs. But make no mistake, all other things equal, a 20w40 will outperform a 5w40 at hgih temperature, but flow more poorly in the cold. For most "appliance" owners, this is likely NOT a good trade-off, but for me at the track or mixed track/street use ( and using my brain) - it IS a good thing.
That's the big point. There are few"good" or "bad" oils. There are oils with different characteristics, and we need to pick them knowing how they will be used, or, conversely, modify our use to suit them.
Similarly there are a few things that are simply "better". Oils with hgih TBNs will counteract acids longer (duh). Changing oils maintains its additive package, avoids shear, and discards accumulated acids and water.
Grant
Grant
gee-lenahan-at-gee-mail-dot-com
| Re: Yea, i keep bringing it up because... Guenter in Ontario - Tuesday, 8 October, 2013, at 8:41:07 am |
Quote
grant
For the rest of the world, i'm sure that relatively fresh 5w30 is fine. Just don't expect it to protect at 100+ deg C and hgih rpms. Which, on my morning commute occurs roughly, well, never.
Grant
Interesting about that 100+ deg C. Since the 981 displays oil as well as coolant temperatures. Once warmed up, it's quite normal for the oil to run 100+ C on the highway. The harder you drive it, the warmer the oil gets. What always surprises me is how quickly the oil temperature drops when driving slowly or sitting and idling.
From a cold start, it takes a LOT longer for the oil to reach operating temperature than it takes the coolant. I think it's part of the 981 thermal management. Coolant will be near operating temperature (90 C on Canadian cars) before the oil temperature begins to rise much above ambient temperature. At around 20 C (68 F) it can take anywhere from 10 - 15 minutes for the engine to reach operating temperature. For me, I consider that to be 90 C for coolant and oil temperature. I always avoid hard acceleration and high RPM's before the engine is fully warmed up.
| That's pretty hot. I dont have a oil temp guage in my boxster, but grant - Tuesday, 8 October, 2013, at 11:08:35 am |
In my Audi i typically run about 170-190 degF; on the track i have hit 230-240F. That was a hot day, running dfoot to floor pretty much all the time (pocono).
100 degC is simply the typical temp for hot viscosity measurements. Note there is no magic number; there's a fairly smoo9th viscosity curve vs temperature.
Grant
Grant
gee-lenahan-at-gee-mail-dot-com
Edited 1 time(s). Last edit at 10/08/2013 11:10AM by grant. (view changes)
100 degC is simply the typical temp for hot viscosity measurements. Note there is no magic number; there's a fairly smoo9th viscosity curve vs temperature.
Grant
Grant
gee-lenahan-at-gee-mail-dot-com
Edited 1 time(s). Last edit at 10/08/2013 11:10AM by grant. (view changes)
| Re: That's pretty hot. I dont have a oil temp guage in my boxster, but Guenter in Ontario - Tuesday, 8 October, 2013, at 2:33:32 pm |
Quote
grant
In my Audi i typically run about 170-190 degF; on the track i have hit 230-240F. That was a hot day, running dfoot to floor pretty much all the time (pocono).
100 degC is simply the typical temp for hot viscosity measurements. Note there is no magic number; there's a fairly smoo9th viscosity curve vs temperature.
Grant
Just got back from taking care of a few things around town. Once the engine was completely warmed up, oil temp was between 100 C - 103 C (212 - 218 F) while the engine was running. Ambient temperature is about 65 F
MikenOH - Tuesday, 8 October, 2013, at 5:25:38 pm |
Quote
Guenter in Ontario
Quote
grant
For the rest of the world, i'm sure that relatively fresh 5w30 is fine. Just don't expect it to protect at 100+ deg C and hgih rpms. Which, on my morning commute occurs roughly, well, never.
Grant
From a cold start, it takes a LOT longer for the oil to reach operating temperature than it takes the coolant. I think it's part of the 981 thermal management. Coolant will be near operating temperature (90 C on Canadian cars) before the oil temperature begins to rise much above ambient temperature. At around 20 C (68 F) it can take anywhere from 10 - 15 minutes for the engine to reach operating temperature. For me, I consider that to be 90 C for coolant and oil temperature. I always avoid hard acceleration and high RPM's before the engine is fully warmed up.
Longer than you think, Guenter. With my OBDll reader plugged in, the coolant temp on the smart phone mirrored the display on the car until about 35 deg. C, then the temperature on the car's gauge seemed to raise faster than the OBD, stopping at exactly 93 deg.C. The OBD display hit 103C and then dropped off.
The advice on keeping the throttle inputs low until fully warmed is good advice; it takes a good 15 minutes of driving to get the engine oil warned up close to the coolant temp/
| And its not like we need to drive weasy until its 95 dec C - opil is flowing incrementally grant - Tuesday, 8 October, 2013, at 7:21:15 pm |
better for every degree rise. in a car with a oil temp gauge, any actual movement says, to me, "drive normally" - not "run to redline and stay there" but "normally".
The real problem is with oil down around -10C --> maybe 50C. You can see viscosity curves at lubrizol.com. They look mostly as you would expect.
S-shaped.
Grant
Grant
gee-lenahan-at-gee-mail-dot-com
The real problem is with oil down around -10C --> maybe 50C. You can see viscosity curves at lubrizol.com. They look mostly as you would expect.
S-shaped.
Grant
Grant
gee-lenahan-at-gee-mail-dot-com
| Well, I'm no oil expert but my recollection is the concerns about VIIs... MarcW - Tuesday, 8 October, 2013, at 10:24:44 am |
belongs in the mineral oil world. Synthetic oils obtain their multi-viscosity attributes organically, as a function of their chemical make up, not through more artificial means.
In fact your whole post seems tied to mineral oil issues/concerns. Sludge? Not once has sludge appeared to be an issue with modern Porsche engines and it is not like it would remain hidden. I recall with at least one automaker -- Toyota -- with an engine that had a sludge problem, a real problem, not an imagined or hypothetical problem and the problem became well known, enough so that Toyota had to deal with it in a very public way.
If you are using your Porsche in a manner not sanctioned by Porsche you are free to select whatever oil you feel will suit the usage. But this in no way qualifies you to make recommendations on what oil to use for those owners who do not venture off the road onto to track with their Porsches.
I can't dispute your claim you make regarding 20w-40 being better than a 5w-40 oil. I can only to point out that things are not equal. By not having a 20w-40 oil (or a 10w-xx oil, or a 15-xx oil) on its approved list either Porsche recognizes things are not equal and 20w-40 (and other) oils do not measure up or Porsche simply blew the call. I chose to believe it is the former not the latter.
In fact your whole post seems tied to mineral oil issues/concerns. Sludge? Not once has sludge appeared to be an issue with modern Porsche engines and it is not like it would remain hidden. I recall with at least one automaker -- Toyota -- with an engine that had a sludge problem, a real problem, not an imagined or hypothetical problem and the problem became well known, enough so that Toyota had to deal with it in a very public way.
If you are using your Porsche in a manner not sanctioned by Porsche you are free to select whatever oil you feel will suit the usage. But this in no way qualifies you to make recommendations on what oil to use for those owners who do not venture off the road onto to track with their Porsches.
I can't dispute your claim you make regarding 20w-40 being better than a 5w-40 oil. I can only to point out that things are not equal. By not having a 20w-40 oil (or a 10w-xx oil, or a 15-xx oil) on its approved list either Porsche recognizes things are not equal and 20w-40 (and other) oils do not measure up or Porsche simply blew the call. I chose to believe it is the former not the latter.
| VIIs adn better vs different grant - Tuesday, 8 October, 2013, at 11:23:06 am |
belongs in the mineral oil world. Synthetic oils obtain their multi-viscosity attributes organically, as a function of their chemical make up, not through more artificial means.
--> common misconception. I was speaking specifically of Synthetics, whcih, i'll note are a family, not a thing, adn int he end are nearly identical to traditional oil - they are simply more uniform molecules. There are many tricks to achieve wide viscosity ranges, but they all have trade-offs. Many VIIs are still used - go loo them up ont he lubrizol site.
In fact your whole post seems tied to mineral oil issues/concerns.
--> Nope, but read above, they are not that different, really. They are methods, not things.
Sludge? Not once has sludge appeared to be an issue with modern Porsche engines and it is not like it would remain hidden. I recall with at least one automaker -- Toyota -- with an engine that had a sludge problem, a real problem, not an imagined or hypothetical problem and the problem became well known, enough so that Toyota had to deal with it in a very public way.
--> sludge is the accumulation of thickened by-products in the oil. Its first effect is to raise the pour point and low-temp viscosity. Its next effect is to begin coating and maybe constricting oil passages. It may be subtle, but most concerns about oil in normal use are subtle. Toyota, Audi, VW, renault all had major sludge issues, many involved recalls.
If you are using your Porsche in a manner not sanctioned by Porsche you are free to select whatever oil you feel will suit the usage. But this in no way qualifies you to make recommendations on what oil to use for those owners who do not venture off the road onto to track with their Porsches.
--> Bingo, whcih is why i suggest that people quit asking about "goood or bad" and ask "what characteristics do i need". I find the "porsche says" answer equally bad - it assumes all uses are the ame, and it assumes Porsche has the same goals i do or you do. They don't.
I can't dispute your claim you make regarding 20w-40 being better than a 5w-40 oil.
--> You should. I was as clear as possible in saying it is NOT BETTER, it is DIFFERENT
Please don;t change the meaning of my statements. What i wrote, verbatim, was:
"That's the big point. There are few"good" or "bad" oils. There are oils with different characteristics,
and we need to pick them knowing how they will be used, or, conversely, modify our use to suit them."
I can only to point out that things are not equal.
--> Well, then we cannot compare at all. Yep, a group 4 5w40 will likely do better at 120 C than a dino, recycled 20w40. We cannot discuss the merits of a specification if we allow all the other specifications to flopat. One variable, one equation. Sorry, that's life.
By not having a 20w-40 oil (or a 10w-xx oil, or a 15-xx oil) on its approved list either Porsche recognizes things are not equal and 20w-40 (and other) oils do not measure up or Porsche simply blew the call. I chose to believe it is the former not the latter.
--> They know that most owners will use the cars in cold conditions, will not warm them up, etc. They want one oil that they can simply say "put it in and it will work". Ideally that's 0w100. Hard to find in my local FLAPS, though. So i sugegst we go back to my actual statement, whcih was that:
"we need to pick them knowing how they will be used, or, conversely, modify our use to suit them."
..So if you buy 20w40, knowing its great whyen hot but loousy when cold, be careful when its cold. if that's too complicate or unacceptable, don't buy it.
Grant
Grant
gee-lenahan-at-gee-mail-dot-com
--> common misconception. I was speaking specifically of Synthetics, whcih, i'll note are a family, not a thing, adn int he end are nearly identical to traditional oil - they are simply more uniform molecules. There are many tricks to achieve wide viscosity ranges, but they all have trade-offs. Many VIIs are still used - go loo them up ont he lubrizol site.
In fact your whole post seems tied to mineral oil issues/concerns.
--> Nope, but read above, they are not that different, really. They are methods, not things.
Sludge? Not once has sludge appeared to be an issue with modern Porsche engines and it is not like it would remain hidden. I recall with at least one automaker -- Toyota -- with an engine that had a sludge problem, a real problem, not an imagined or hypothetical problem and the problem became well known, enough so that Toyota had to deal with it in a very public way.
--> sludge is the accumulation of thickened by-products in the oil. Its first effect is to raise the pour point and low-temp viscosity. Its next effect is to begin coating and maybe constricting oil passages. It may be subtle, but most concerns about oil in normal use are subtle. Toyota, Audi, VW, renault all had major sludge issues, many involved recalls.
If you are using your Porsche in a manner not sanctioned by Porsche you are free to select whatever oil you feel will suit the usage. But this in no way qualifies you to make recommendations on what oil to use for those owners who do not venture off the road onto to track with their Porsches.
--> Bingo, whcih is why i suggest that people quit asking about "goood or bad" and ask "what characteristics do i need". I find the "porsche says" answer equally bad - it assumes all uses are the ame, and it assumes Porsche has the same goals i do or you do. They don't.
I can't dispute your claim you make regarding 20w-40 being better than a 5w-40 oil.
--> You should. I was as clear as possible in saying it is NOT BETTER, it is DIFFERENT
Please don;t change the meaning of my statements. What i wrote, verbatim, was:
"That's the big point. There are few"good" or "bad" oils. There are oils with different characteristics,
and we need to pick them knowing how they will be used, or, conversely, modify our use to suit them."
I can only to point out that things are not equal.
--> Well, then we cannot compare at all. Yep, a group 4 5w40 will likely do better at 120 C than a dino, recycled 20w40. We cannot discuss the merits of a specification if we allow all the other specifications to flopat. One variable, one equation. Sorry, that's life.
By not having a 20w-40 oil (or a 10w-xx oil, or a 15-xx oil) on its approved list either Porsche recognizes things are not equal and 20w-40 (and other) oils do not measure up or Porsche simply blew the call. I chose to believe it is the former not the latter.
--> They know that most owners will use the cars in cold conditions, will not warm them up, etc. They want one oil that they can simply say "put it in and it will work". Ideally that's 0w100. Hard to find in my local FLAPS, though. So i sugegst we go back to my actual statement, whcih was that:
"we need to pick them knowing how they will be used, or, conversely, modify our use to suit them."
..So if you buy 20w40, knowing its great whyen hot but loousy when cold, be careful when its cold. if that's too complicate or unacceptable, don't buy it.
Grant
Grant
gee-lenahan-at-gee-mail-dot-com
Laz - Tuesday, 8 October, 2013, at 10:45:49 am |
| A3/B4 and HTHS - doesn;t matter? grant - Tuesday, 8 October, 2013, at 11:29:46 am |
I find that question curious. Why would it not matter what the film strength is at hgih temperatures, rpms, and presures?
ACEA A3 basically = HTHS shear. and loosens the requirements for fuel economy, drain interval and other more appliance related goals.
(note that A4 does not loosen these as much)
That's the perfect storm. That's what i select oils to protect. The rest is easy, once they flow.
Grant
Grant
gee-lenahan-at-gee-mail-dot-com
ACEA A3 basically = HTHS shear. and loosens the requirements for fuel economy, drain interval and other more appliance related goals.
(note that A4 does not loosen these as much)
That's the perfect storm. That's what i select oils to protect. The rest is easy, once they flow.
Grant
Grant
gee-lenahan-at-gee-mail-dot-com
| OK, now i'll take 10 minutes grant - Tuesday, 8 October, 2013, at 11:52:04 am |
Please bear in mind i like what i read here - mostly.
I'm just nibbling at the edges.
Grant
gee-lenahan-at-gee-mail-dot-com
I'm just nibbling at the edges.
Quote
Jim in Iowa
others call it (or Mobil, in particular) a marketing scheme.
--> its both. But anyone in the busines knows these are paid for endorsements.
The PCA's tech editor Alan Caldwell (a retired Boeing engineer) did an extensive look at oils, and concluded that so long as the oil is Porsche-approved, and the second number in the formulation is 40 or higher, change at factory intervals, and you are good to go.
--> the problem is that car's duty cycles are different. If you drive the car regularly, adn get the oil hot, and burn the moisture offr, and dont add too many acids, then yes. If all those if's dont occur, then no. And there are wide differences in the Totoal Base Number for A40 oils, so they simply can;t be identical in terms of counter-acting acid.
Excellence magazine's tech staff recommends using Motul, often with much more frequent than the factory recommended change intervals. You'll see a bunch of other places recommend changing oil every 3K miles.
--> in general i think that buying by brand is misleading. Buy by numbers. Changing frequently is also good, btu one has to know why, adn beyond x its just wasteful. Interestingly, when i do UOAs my track cars have vastly lower dilution - THEY GET HOT
One really interesting question I saw posed at the 2009 Mobil 1 Parade tech session, during the 9x7 generation of cars, Porsche shortened the drain interval. I forget the exact number, but maybe it went from 15K down to 12K, something like that. Someone in the audience asked was that interval change due to the high frequency of ethanol in most U.S. gasoline, and as the alcohol is a solvent, does it strip the lubrication from the cylinder walls faster and break the oil down more quickly? Nobody answered that question, unfortunately.
1. Theyhave done thsi several times
2. moisture and acid are typically the enemy
Then of course there is the lowering of the ZDDP levels in oil in the last few years, a source of great consternation.
--> one reason, and its no secret - to protect catalytic converters. But i pose this: if your car burns no oil, how does the Zddp get to the cat?
To paraphrase Mobil's position, they told us that there are only two mass producers of the synthetic oil base stock in the world, Exxon-Mobil was one, and I forget the other, it might have been Royal Dutch Shell. So all of the various boutique oils are using one of the major's base stock, and putting in their own additive package.
--> not true. Maybe they make 85% or something, but there are small makers. Heck, look at the BP-EM lawsuit.
As to the ZDDP drop, Mobil says that's due to the EPA getting after the SAE (Society of Automotive Engineers), who do the oil certification. The EPA wants more life out of catalytic converters, I want to say a certain amount of effectiveness at 10 years instead of 8. The zinc and phosphorus metals build-up inside the cat, reducing its effectiveness over time.
--> absolutely correct, btu look above. Only if your car burns substantial oil.
Mobil says that ZDDP is a very cost-effective anti-wear additive, hence its widespread use. It's a relatively old additive, dating back to the late 1940s. They note that it's not the *only* anti-wear additive in the oil formulation array, nor is it magic, there are others, but they are generally newer and more expensive. ZDDP was popular because it works, and is low oost.
--> its about protection when you switch from hydrdynamic lubrication ( e.g.: oil film) to barrier lubrication (e.g.: oops, my oil failed at hgih temps and rpms)
The engines reportedly most prone to wear issues are those with "flat tappet' engines, such as the original Beetle. Mobil said that no Porsche motor from the 911 (1964) onward has that flat tappet condition (not sure on 356s).
--> yep, for us it only matetrs when the ehem, hits the fan
Some users have become fixated on reduced levels of ZDDP as being the potiential cause for many ills. Hemming's, the classic car car magazine, even markets a self-branded oil with high levels of ZDDP, "to protect your engine."
--> they are in the old car game. We are not.
Mobil, being aware of this stumbling block, has their "Racing" line of Mobil 1, so anyone insistent upon high ZDDP levels can get it. The EPA generally won't concern themselves with a "racing' labeled product, as they assume that's for off-road use, or small potatoes on road.
--> IMNSHO you are better off racing with oil that wont fail hydrdynamic lubrication. e.g.: hgih viscosity; low vis range; astronomical HTHS number. Oddly, this may be a hgih wear oil. But wear does nto mean "total film failure"
So that brings me to the lab again. When I asked what levels of increased wear were they seeing with these newer low ZDDP oils, the answer is "None." They base their judgment of how an oil is doing upon the wear metals coming out of the engine, and the measured characteristics of the oil. So it's interesting to see that wear metals are no different with lower ZDDP.
--> bingo per my above. If the film does nto fail, and the acid is neutralized, and the water boils off, under normal lubruication, wear is a non-issue. Problem is, many circumstances cause those failures. I would go out on a limb and say IMS's succumb to acid and water; track cars to oil film failure (or starvation of coruse, another topic)
Moreover, the flat tappet engines that have people so worried about wear, they're not showing up with any elevation in wear metals, either. When I asked for possible reasons why, he said they were using other anti-wear agents to replace the ZDDP, most often molybendum.
My next question was how do the various Porsche-approved synthetic oils do in their wear metals profile? Is Motul or Shell Helix, for example, better than Mobil 1? He said their lab hasn't seen any significant differences, they all do a fairly equal, excellent job. It's also interesting to note that the unit location averages in your oil report are for your type of engine, not all engines. So if you've got a 3.2L M96, they'll show you averages for other 3.2L M96s. I asked how big the population was for that group, and he said around 200 motors.
--> as i said
I then asked about interval changes. He said that during warranty, it's important to always follow the manufacturer's guidance. He added that 95% of the oil samples that they receive *didn't *need to have their oil changed. The oil was not worn out, nor was there too many wear particles in it. So much for the 3,000 mile oil change myth vs. data.
--> i agree about 3k for modern oils being short. But 1) it depends on your use 2) there is a giant self-selection bias in those who submit to UOA - they CARE. A 3k mile oil in a 1500 mile per year garage queen will be 30% oil 30% acid and 30% water,a dn 10% low. I'm exagerating, of course.
I asked what about time? Should engines always have their oil changed in selected time? That's usually once a year for Porsche. He said in warranty, always follow the rules. Out of warranty, mileage is more important. For automotive engines, they're so "tight' when it comes to environmental exposure (per the EPA), you don't have to worry about time so much. Now for piston-driven aviation engines, time is far more important because they're not as tightly sealed.
-->>no, no, no. That's literally true, but practically unlikel;y. Think about the characteristics by whcih a car gets to long time intervals but low miles. Sits. Accumulates water. Not too much use. Maybe rarely gets the oil hot for 30 minutes. In when it does, how hot? There will always be exceptions, but i would guess that garage queens have some of the worse dilution issues going. The best way to fix those is change the oil. Heck, use $8/jug dino. Its ph neutral at least!
I said hypothetically speaking, if you bought a new Porsche, would you change the oil early, or wait for the full year or 12K miles? He said he'd be tempted to change maybe before a winter storage to get the wear metals out, but you probably don't need to do it. He said most German engines these days don't throw off much in the way of wear metals, anyway.
--> again, its nto about wear metals. Its about shear (if you are a track rat), water and acid.
So it sounds as though Alan Caldwell's advice really is a safe way to go without overthinking it.
__> I prefer Einstein: things should be made as simple as possible, btu no simpler. we may have achieved "simpler than possible"
Thought you'd all be interested.
Grant
gee-lenahan-at-gee-mail-dot-com
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