Oil change, what viscosity do you use??
10-10-2012, 10:00 AM
#46
Three Wheelin'
Join Date: May 2007
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No offence to anyone here...., but
talk about being baffled by science.., I reckon by the end of this post we will all be as wise as we were at the beginning.
, and the debate now and in future will continue ?
Iv,e always used Castrol 10-40 semi synth, have done for some years now and she runs sweet.
It,s probably a case of " Horses for courses " an English addage ?
Ken
80 928S
5 Speed
UK
talk about being baffled by science.., I reckon by the end of this post we will all be as wise as we were at the beginning.
, and the debate now and in future will continue ?
Iv,e always used Castrol 10-40 semi synth, have done for some years now and she runs sweet.
It,s probably a case of " Horses for courses " an English addage ?
Ken
80 928S
5 Speed
UK
10-10-2012, 11:12 AM
#47
Race Car
An engine oil that is good for a Boxster is not necessarily a good oil for the 928. A Boxster engine is radically different from a 928 engine and was designed decades later. For a 928 in southern states in North America, it is IMO mandatory to have a 50W hot oil in a 928 in the summer. I find that even M1 15W-50 can be a little too thin when it gets very hot ambient and humid.
Dan
'91 928GT S/C
475hp/460lb.ft
Dan
'91 928GT S/C
475hp/460lb.ft
10-10-2012, 01:35 PM
#48
Pro
Here's what a true expert has to say on oil, however it may not apply to your boxster, so you should probably go to this forum: https://rennlist.com/forums/boxster-...-986-forum-67/
From Bruce Buchanan
Last century Porsche engines very much need high oil film strength engine oils if one wants as much long life as possible out of items that have no oil pressure keeping the metal parts away from each other , such as }
A ) valve guides ( air cooled 911 huge wear issue )
B ) Cam lobes & hydraulic lifter faces ( flat tappet design )= 944 / 928
C) Crankshaft thrust bearings
D) Camshaft chain sprockets ( 944 & 928 twin cam heads)
E) Alloy piston skirts against alloy cylinders
F) 911 air cooled rocker arms contact faces with cam lobes
All the above we have seen exceptional wear , meaning high wear , when these engines have been on low viscosity so called synthetic engine oils , and conversely we have little or no wear on the same types( & 3 times the milage) where they have been on the oil viscosities recommended by Porsche that is printed in the owners manual that came with the car new .
So on a last century Porsche }
911 air cooled ( all year types )
924
931
944
944S
944S2
928 ( 4.5L , 4.7L, 5.0L , 5.4L )
968
951
We see in the owners manual on the oil viscosity page , the oil chart showing ambient temp ranges
In the "Look at me " shaded section of this page under the heading of multi grade oils we see the first ambient temp range of = minus 10 deg cel to unlimited high ambient temp ( sounds like Australia to me ) , we then see the recommendation of a 20w-50 & 15w-50 ,
One does not see 5w-40 etc in this temp range
Note } in Porsche cars ( 928 , 911 , 944 etc ) up to about 1983 or so the ambient temp range for a 20w-50 was minus 15 deg cel to unlimited high temp range
Now lets go to engine oil film strength }
Question = how do I increase oil film strength with an engine oil on this planet in this universe ?
Answer = there are two basic ways
1) increase the oil viscosity ( say from a 5w-40 to a 20w-50) if both oils have the same amount of ZDDP
2) increase ZDDP or add Molybdenum ( in conjunction with ZDDP ),which enhances the effectiveness & life of the ZDDP
So if you add the two ( meaning 20w-50 & ZDDP ) = high oil film strength
Subnote } most if not all 20w-50 engine oils are OK in respect to their ZDDP amounts , because last century engine's & oils are not subject to this century emission protocols , most cars in this century use much lower viscosites ( engines designed for this)& to meet the emission protocols( lower levels of ZDDP & no Moly), meaning 0w-30 , 0w-40 , 5w-40 oils for this century cars are generally lower in their oil film strengths as compared to a 20w-50 with ZDDP , even though the replacement AW ( anti wear additive) of ZDDP ( read Boron ) has not been as useful in regards to increasing oil film strength as ZDDP was / is in last century viscosities.
There was even one famous oil company here in Australia that experimented with dropping the amount of ZDDP in their 15w-50 just over a decade ago & that was interesting , we saw quite a few worn cams and above parts mentioned above within 60,000Kms( on average) , Oh and by the way the same oil reverted back to a higher ZDDP ( it can be a bit of a mine field at times)
So you can see why I am not easy about recommending even a 15w-50 , even though it was probably a one off
The reason we can figure that easily is one only has to look at the advertising for this century racing oils for "this" century engines & oil companies are falling over each other to show how much ZDDP is in their racing oils , and yes they are not falling over each other to show how much more Boron or any other AW additive they have added , they just go on about ZDDP , so it must work over wise they would just say things like " we have added twice the amount of non ZDDP AW replacement like Boron etc " , well this is not happening , its ZDDP , yep last century solutions in this century racing oils ( who would have guessed that )
Now lets go to primary diesel engine oils , like Delvac etc , excellent oil for a diesel engine that is designed for that viscosity , however Mobil & Porsche do not recommend a diesel oil in a petrol powered engine , not last century & not in this century
Now why is that so ?
Answer = primary diesel oils are very high in detergents( compared to petrol powered oils) and these detergent packages tend to make engine oil foam too easily , so they then add silicon to reduce this tendency , but detergents attack the ZDDP , thats why primary diesel oils look as if they have very high ZDDP( new) , but as time goes by the ZDDP is damaged by the detergent packages .
Now back to the foaming , if a petrol engine from last century revs harder to make its max power as opposed to a diesel engine from last century ( like for like) this in quite normal , so in a big rig that cruises on the freeway at 1,800 RPM will give the oil way less tendency to foam as say a sports car / GT engine that is being revved to 6,500 RPM a lot .
This is where it gets interesting , foaming / air bubbles in the oil is the VERY last thing you need in a 944 / 951 or a 928 , because they have a very small flaw in their crank oil feed design , they starve no 2 con rod bearing ( 944 / 951 / 968 ) and 2& 6 con rod bearings on a 928 if the oil pressure drops to low.
How do we drop the oil pressure with a high core temp ?
Answer = use a 5w-40 oil ( in Australia) , then make it a diesel engine oil that will foam more easily & you are putting the bottom end at risk for not net gain what so ever
How do we reduce / eliminate this from happening ?
Answer = we consult the owners manual ( very easy stuff to understand)
Question = Do we see people destroy last century Porsche engines at the track when they are running even slightly lower viscosities ?
Answer = used to be very common , now getting better as people get better educated by reading their owners manual
Question = How do we eliminate this human tendency of wanting to use this century oils in last century Porsche engines .
Answer = Education .
Now onto oil pressure for a bit , we used to get ( every summer ) 928 ( all types) 944 / 951/968 turn up at our workshop with their oil pressure warning light glowing brightly at idle , naturally its a hot day & they have spent a few hours crawling in heavy traffic to get this high core temp ( no not coolant temp ) I mean core oil temp , and this is normally due to 5w-40 , we even get the odd one do it on a 10w-40 , so for these conditions the only thing that works is a 20w-50 ( never fails ( so long as the engine is not already badly damage by running around with a low vis oil
Remember , if the oil warning light is on at idle , then you can not go for full power because the con rod bearings are at severe risk at high revs , on a 20w-50 this will not occur .
Regards
Bruce Buchanan
Buchanan Automotive
From Bruce Buchanan
Last century Porsche engines very much need high oil film strength engine oils if one wants as much long life as possible out of items that have no oil pressure keeping the metal parts away from each other , such as }
A ) valve guides ( air cooled 911 huge wear issue )
B ) Cam lobes & hydraulic lifter faces ( flat tappet design )= 944 / 928
C) Crankshaft thrust bearings
D) Camshaft chain sprockets ( 944 & 928 twin cam heads)
E) Alloy piston skirts against alloy cylinders
F) 911 air cooled rocker arms contact faces with cam lobes
All the above we have seen exceptional wear , meaning high wear , when these engines have been on low viscosity so called synthetic engine oils , and conversely we have little or no wear on the same types( & 3 times the milage) where they have been on the oil viscosities recommended by Porsche that is printed in the owners manual that came with the car new .
So on a last century Porsche }
911 air cooled ( all year types )
924
931
944
944S
944S2
928 ( 4.5L , 4.7L, 5.0L , 5.4L )
968
951
We see in the owners manual on the oil viscosity page , the oil chart showing ambient temp ranges
In the "Look at me " shaded section of this page under the heading of multi grade oils we see the first ambient temp range of = minus 10 deg cel to unlimited high ambient temp ( sounds like Australia to me ) , we then see the recommendation of a 20w-50 & 15w-50 ,
One does not see 5w-40 etc in this temp range
Note } in Porsche cars ( 928 , 911 , 944 etc ) up to about 1983 or so the ambient temp range for a 20w-50 was minus 15 deg cel to unlimited high temp range
Now lets go to engine oil film strength }
Question = how do I increase oil film strength with an engine oil on this planet in this universe ?
Answer = there are two basic ways
1) increase the oil viscosity ( say from a 5w-40 to a 20w-50) if both oils have the same amount of ZDDP
2) increase ZDDP or add Molybdenum ( in conjunction with ZDDP ),which enhances the effectiveness & life of the ZDDP
So if you add the two ( meaning 20w-50 & ZDDP ) = high oil film strength
Subnote } most if not all 20w-50 engine oils are OK in respect to their ZDDP amounts , because last century engine's & oils are not subject to this century emission protocols , most cars in this century use much lower viscosites ( engines designed for this)& to meet the emission protocols( lower levels of ZDDP & no Moly), meaning 0w-30 , 0w-40 , 5w-40 oils for this century cars are generally lower in their oil film strengths as compared to a 20w-50 with ZDDP , even though the replacement AW ( anti wear additive) of ZDDP ( read Boron ) has not been as useful in regards to increasing oil film strength as ZDDP was / is in last century viscosities.
There was even one famous oil company here in Australia that experimented with dropping the amount of ZDDP in their 15w-50 just over a decade ago & that was interesting , we saw quite a few worn cams and above parts mentioned above within 60,000Kms( on average) , Oh and by the way the same oil reverted back to a higher ZDDP ( it can be a bit of a mine field at times)
So you can see why I am not easy about recommending even a 15w-50 , even though it was probably a one off
The reason we can figure that easily is one only has to look at the advertising for this century racing oils for "this" century engines & oil companies are falling over each other to show how much ZDDP is in their racing oils , and yes they are not falling over each other to show how much more Boron or any other AW additive they have added , they just go on about ZDDP , so it must work over wise they would just say things like " we have added twice the amount of non ZDDP AW replacement like Boron etc " , well this is not happening , its ZDDP , yep last century solutions in this century racing oils ( who would have guessed that )
Now lets go to primary diesel engine oils , like Delvac etc , excellent oil for a diesel engine that is designed for that viscosity , however Mobil & Porsche do not recommend a diesel oil in a petrol powered engine , not last century & not in this century
Now why is that so ?
Answer = primary diesel oils are very high in detergents( compared to petrol powered oils) and these detergent packages tend to make engine oil foam too easily , so they then add silicon to reduce this tendency , but detergents attack the ZDDP , thats why primary diesel oils look as if they have very high ZDDP( new) , but as time goes by the ZDDP is damaged by the detergent packages .
Now back to the foaming , if a petrol engine from last century revs harder to make its max power as opposed to a diesel engine from last century ( like for like) this in quite normal , so in a big rig that cruises on the freeway at 1,800 RPM will give the oil way less tendency to foam as say a sports car / GT engine that is being revved to 6,500 RPM a lot .
This is where it gets interesting , foaming / air bubbles in the oil is the VERY last thing you need in a 944 / 951 or a 928 , because they have a very small flaw in their crank oil feed design , they starve no 2 con rod bearing ( 944 / 951 / 968 ) and 2& 6 con rod bearings on a 928 if the oil pressure drops to low.
How do we drop the oil pressure with a high core temp ?
Answer = use a 5w-40 oil ( in Australia) , then make it a diesel engine oil that will foam more easily & you are putting the bottom end at risk for not net gain what so ever
How do we reduce / eliminate this from happening ?
Answer = we consult the owners manual ( very easy stuff to understand)
Question = Do we see people destroy last century Porsche engines at the track when they are running even slightly lower viscosities ?
Answer = used to be very common , now getting better as people get better educated by reading their owners manual
Question = How do we eliminate this human tendency of wanting to use this century oils in last century Porsche engines .
Answer = Education .
Now onto oil pressure for a bit , we used to get ( every summer ) 928 ( all types) 944 / 951/968 turn up at our workshop with their oil pressure warning light glowing brightly at idle , naturally its a hot day & they have spent a few hours crawling in heavy traffic to get this high core temp ( no not coolant temp ) I mean core oil temp , and this is normally due to 5w-40 , we even get the odd one do it on a 10w-40 , so for these conditions the only thing that works is a 20w-50 ( never fails ( so long as the engine is not already badly damage by running around with a low vis oil
Remember , if the oil warning light is on at idle , then you can not go for full power because the con rod bearings are at severe risk at high revs , on a 20w-50 this will not occur .
Regards
Bruce Buchanan
Buchanan Automotive
10-10-2012, 08:40 PM
#49
lol, good luck with that.
Is this acceptable, a Porsche graphic...
Sorry, some local guy's decade-old rant just doesn't do it for me. An "expert" would be proficient in basic and advanced tribology, I'm just seeing a bunch of scientific terms tossed into a jar and shaken up, and what comes out is just jibberish.
Doesn't anyone understand the difference between theory and empirical evidence? If someone says, oh, HIGH zddp is necessary, tell us WHY. Tell us HOW zddp works. SHOW us the DATA, this formulation verses that formula.
It's almost a joke to speak in terms of SAE grades, 40, 50 and so on, not the technical units of centistrokes, or the unit that defines how an oil "protects", the High-Temp / High-Shear rating in centipoise. Oils can have relative higher or lower HT/HS for their given grade. 3.5cP is the target for all Euro specs, and is met by a few 30 weight oils, some with Porsche Approval. All the newest spec oils ARE 5w-30, inc Porsche A30. Is that common knowledge? idk.
I guess nobody googled Dr.Hass. He's about as far from some local-yokel snake oil expert as you can get. I don't think anyone even clicked my links either, because if you did you might actually have a comment or question on it. Sorry, I over-estimated the forum.
EVERY oil I know contains zddp, most are at or near 1000ppm. You're going to sit there and tell me that, DESPITE all the advances in lube and additive technology, simply adding a bit more zink and visc solves everything and makes all the difference if an engine will survive or not? Come on guys. I know how insecure and defensive people get with their anecdotal oil science stories. Use your head. A 40 weight is just as "thick" as a 50 until it gets heated beyond the normal, stable 100c. Adding visc gives diminishing returns at elevated temps. Here's a graph for those who remember high school science...
See how the supposed margin of protection decreases with oil temp, and they all nearly converge in the extreme? Oh, what else, the viscs overlap, sometimes twice! Also, do we all realize that thicker oil adds to the heat load, not decreases it? That's right, thick oil drives up temps and adds parasitic losses. Thin oil cools BETTER because it FLOWS better. Does pressure cool a main journal bearing??? Umm, no. FLOW cools bearings. pressure is inversely related to flow- the opposite. Well, why do mechanics look at pressure? It's because flow metering is difficult on a mobile platform over a wide operating range. Pressure gauge is a simple device.
Oh, and if you want to bite down on Mobil 1 Red Cap 15w-50, MY well-known Porsche mechanic claims almost every blown engine he sees has a jug of Red Cap in the rear. It's been unformulated just like the oils that get improperly condemned.
Do what you will, at least now you have something to go with other than random guesses. Show me a scientific white paper less than 5 or 10 years old that rules out any other additives than a little bit extra zddp, and an increase in visc. Guess what, there are none and ALL the data indicates the opposite.
Everyone seems to know all the answers and no one has any questions, so see ya.
Is this acceptable, a Porsche graphic...
Sorry, some local guy's decade-old rant just doesn't do it for me. An "expert" would be proficient in basic and advanced tribology, I'm just seeing a bunch of scientific terms tossed into a jar and shaken up, and what comes out is just jibberish.
Doesn't anyone understand the difference between theory and empirical evidence? If someone says, oh, HIGH zddp is necessary, tell us WHY. Tell us HOW zddp works. SHOW us the DATA, this formulation verses that formula.
It's almost a joke to speak in terms of SAE grades, 40, 50 and so on, not the technical units of centistrokes, or the unit that defines how an oil "protects", the High-Temp / High-Shear rating in centipoise. Oils can have relative higher or lower HT/HS for their given grade. 3.5cP is the target for all Euro specs, and is met by a few 30 weight oils, some with Porsche Approval. All the newest spec oils ARE 5w-30, inc Porsche A30. Is that common knowledge? idk.
I guess nobody googled Dr.Hass. He's about as far from some local-yokel snake oil expert as you can get. I don't think anyone even clicked my links either, because if you did you might actually have a comment or question on it. Sorry, I over-estimated the forum.
EVERY oil I know contains zddp, most are at or near 1000ppm. You're going to sit there and tell me that, DESPITE all the advances in lube and additive technology, simply adding a bit more zink and visc solves everything and makes all the difference if an engine will survive or not? Come on guys. I know how insecure and defensive people get with their anecdotal oil science stories. Use your head. A 40 weight is just as "thick" as a 50 until it gets heated beyond the normal, stable 100c. Adding visc gives diminishing returns at elevated temps. Here's a graph for those who remember high school science...
See how the supposed margin of protection decreases with oil temp, and they all nearly converge in the extreme? Oh, what else, the viscs overlap, sometimes twice! Also, do we all realize that thicker oil adds to the heat load, not decreases it? That's right, thick oil drives up temps and adds parasitic losses. Thin oil cools BETTER because it FLOWS better. Does pressure cool a main journal bearing??? Umm, no. FLOW cools bearings. pressure is inversely related to flow- the opposite. Well, why do mechanics look at pressure? It's because flow metering is difficult on a mobile platform over a wide operating range. Pressure gauge is a simple device.
Oh, and if you want to bite down on Mobil 1 Red Cap 15w-50, MY well-known Porsche mechanic claims almost every blown engine he sees has a jug of Red Cap in the rear. It's been unformulated just like the oils that get improperly condemned.
Do what you will, at least now you have something to go with other than random guesses. Show me a scientific white paper less than 5 or 10 years old that rules out any other additives than a little bit extra zddp, and an increase in visc. Guess what, there are none and ALL the data indicates the opposite.
Everyone seems to know all the answers and no one has any questions, so see ya.
10-10-2012, 08:45 PM
#50
Castrol UK oil finder seems to affirm your choice...
http://www.castrol.com/castrol/secti...tentId=7073092
10-10-2012, 10:42 PM
#51
Owners "Operating Manual" is the way to go. Porsche developed the 928 from a blank sheet of paper and spent millions of $ on its development.
Match up Porsche's recommended oil and refer to the temperature range and you are on the money.
Of course yesterdays development can be tempered by todays operating experience by todays technicians with various new oil types and additives now in the market place.
Don't forget you also have access to Porsche Service Centres or if you are so inclined you can request information from Porsche direct, as to what type of oil is best suited for your model Porsche.
Tails 1990 928S4 Auto
Match up Porsche's recommended oil and refer to the temperature range and you are on the money.
Of course yesterdays development can be tempered by todays operating experience by todays technicians with various new oil types and additives now in the market place.
Don't forget you also have access to Porsche Service Centres or if you are so inclined you can request information from Porsche direct, as to what type of oil is best suited for your model Porsche.
Tails 1990 928S4 Auto
10-11-2012, 12:59 AM
#52
Race Car
Sorry, some local guy's decade-old rant just doesn't do it for me. An "expert" would be proficient in basic and advanced tribology, I'm just seeing a bunch of scientific terms tossed into a jar and shaken up, and what comes out is just jibberish.
Doesn't anyone understand the difference between theory and empirical evidence? If someone says, oh, HIGH zddp is necessary, tell us WHY. Tell us HOW zddp works. SHOW us the DATA, this formulation verses that formula.
It's almost a joke to speak in terms of SAE grades, 40, 50 and so on, not the technical units of centistrokes, or the unit that defines how an oil "protects", the High-Temp / High-Shear rating in centipoise. Oils can have relative higher or lower HT/HS for their given grade. 3.5cP is the target for all Euro specs, and is met by a few 30 weight oils, some with Porsche Approval. All the newest spec oils ARE 5w-30, inc Porsche A30. Is that common knowledge? idk.
Doesn't anyone understand the difference between theory and empirical evidence? If someone says, oh, HIGH zddp is necessary, tell us WHY. Tell us HOW zddp works. SHOW us the DATA, this formulation verses that formula.
It's almost a joke to speak in terms of SAE grades, 40, 50 and so on, not the technical units of centistrokes, or the unit that defines how an oil "protects", the High-Temp / High-Shear rating in centipoise. Oils can have relative higher or lower HT/HS for their given grade. 3.5cP is the target for all Euro specs, and is met by a few 30 weight oils, some with Porsche Approval. All the newest spec oils ARE 5w-30, inc Porsche A30. Is that common knowledge? idk.
EVERY oil I know contains zddp, most are at or near 1000ppm. You're going to sit there and tell me that, DESPITE all the advances in lube and additive technology, simply adding a bit more zink and visc solves everything and makes all the difference if an engine will survive or not? Come on guys. I know how insecure and defensive people get with their anecdotal oil science stories. Use your head. A 40 weight is just as "thick" as a 50 until it gets heated beyond the normal, stable 100c. Adding visc gives diminishing returns at elevated temps. Here's a graph for those who remember high school science...
See how the supposed margin of protection decreases with oil temp, and they all nearly converge in the extreme? Oh, what else, the viscs overlap, sometimes twice! Also, do we all realize that thicker oil adds to the heat load, not decreases it? That's right, thick oil drives up temps and adds parasitic losses. Thin oil cools BETTER because it FLOWS better. Does pressure cool a main journal bearing??? Umm, no. FLOW cools bearings. pressure is inversely related to flow- the opposite. Well, why do mechanics look at pressure? It's because flow metering is difficult on a mobile platform over a wide operating range. Pressure gauge is a simple device.
Oh, and if you want to bite down on Mobil 1 Red Cap 15w-50, MY well-known Porsche mechanic claims almost every blown engine he sees has a jug of Red Cap in the rear. It's been unformulated just like the oils that get improperly condemned.
Oh, and if you want to bite down on Mobil 1 Red Cap 15w-50, MY well-known Porsche mechanic claims almost every blown engine he sees has a jug of Red Cap in the rear. It's been unformulated just like the oils that get improperly condemned.
Do what you will, at least now you have something to go with other than random guesses. Show me a scientific white paper less than 5 or 10 years old that rules out any other additives than a little bit extra zddp, and an increase in visc. Guess what, there are none and ALL the data indicates the opposite.
IMO if you want to go around telling people it's okay to put 5w-30 (or even a 10w-40) oil into their 928 engines that live in hot climates, then you damn well better be prepared to offer up free replacement engines to them with labor WHEN their engines fail.
Dan
'91 928GT S/C
475hp/460lb.ft
10-11-2012, 01:57 AM
#53
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It's good down to -10°C (which I'll never see), and good enough at the top temps the car will see here in Oz. High ZDDP, and regular changes will help also.
10-11-2012, 09:12 AM
#54
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phew!
I'm not usually confused by oils so I'm clearly over-thinking this one, but;
Having read a fair bit I think I've settled on either a 20W50 or possibly a 15W50 for my 16V.
Question is, do I go mineral or synthetic? Some 20W50 oils seem pretty down-market (according to the price), and then there are those listed as 'Extended Life' or '10/10ths driving' - ie priced at the other end. I'm only street driving but it does get mighty hot in the summer here
thanks,
Jim
I'm not usually confused by oils so I'm clearly over-thinking this one, but;
Having read a fair bit I think I've settled on either a 20W50 or possibly a 15W50 for my 16V.
Question is, do I go mineral or synthetic? Some 20W50 oils seem pretty down-market (according to the price), and then there are those listed as 'Extended Life' or '10/10ths driving' - ie priced at the other end. I'm only street driving but it does get mighty hot in the summer here
thanks,
Jim
10-11-2012, 11:52 AM
#55
(imo) Synthetic oil's use is simply for high viscosity index applications, like a 0w-40. Synth base simply is NOT needed to formulate a mundane visc like 10w-30, or a 20w-50.
All oils come from the same HC base. Chemically identical, G-II, G-II+, G-III simply have a higher VI from a longer hydrocrack session, as mentioned before. There really are very very few truly "synthetic" oils on the market.
20w-50 Havoline, Pennzoil, GTX HM, MaxLife, et al, is the functional equivalent of any synthetic 20w-50. The only otc synth 20w-50 with any merit would be SynPower, imo.
20w-50 users, imo, might want to try a 15w-40 for winter. All I ask for is a lil trust in this dept. Everyone rushes to use 15w-50...but it shears to a 40 anyway, is not as good in cold, and offers no physical benefit. Mobil 1 HM 10w-40 looks pretty good in cold for 3.9cP HT/HS (+150c).
Toss a quart of whatever thick oil in the freezer next to a 10w-40 or 10w-30 and check out the result, I guarantee you won't want frozen solid oil in your engine.
All oils come from the same HC base. Chemically identical, G-II, G-II+, G-III simply have a higher VI from a longer hydrocrack session, as mentioned before. There really are very very few truly "synthetic" oils on the market.
20w-50 Havoline, Pennzoil, GTX HM, MaxLife, et al, is the functional equivalent of any synthetic 20w-50. The only otc synth 20w-50 with any merit would be SynPower, imo.
20w-50 users, imo, might want to try a 15w-40 for winter. All I ask for is a lil trust in this dept. Everyone rushes to use 15w-50...but it shears to a 40 anyway, is not as good in cold, and offers no physical benefit. Mobil 1 HM 10w-40 looks pretty good in cold for 3.9cP HT/HS (+150c).
Toss a quart of whatever thick oil in the freezer next to a 10w-40 or 10w-30 and check out the result, I guarantee you won't want frozen solid oil in your engine.
10-12-2012, 02:43 AM
#57
I just brought this home...
http://www.mobil.us/USA-English-LCW/...ge-10w40.aspx#
$3/q every day. +440f flashpoint, not bad. I'm told it's solvent dewaxed Gruppe III base, which is essentially "synthetic" .
I got it because I'm itching to get some HiMiles oil in the car, but don't want to drop in the Mobil 1 HM yet. This is a half-measure for a shorter winter interval of 4 months. I plan on 6 month changes of synth oils.
http://www.mobil.us/USA-English-LCW/...ge-10w40.aspx#
$3/q every day. +440f flashpoint, not bad. I'm told it's solvent dewaxed Gruppe III base, which is essentially "synthetic" .
I got it because I'm itching to get some HiMiles oil in the car, but don't want to drop in the Mobil 1 HM yet. This is a half-measure for a shorter winter interval of 4 months. I plan on 6 month changes of synth oils.
10-12-2012, 02:45 PM
#58
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And I was using normal min. oil something like a 20w-50, and it was funny as hell, I thought the oil was frozen, it was so thick, it was like honey after it gets old.
Try Audi Junkie's freezer idea, its fun to see the effect (just don't let your wife use it for salad oil!)
10-12-2012, 05:36 PM
#60
I'm just providing the info I have. How you apply it is up to you. This thread popped up on top because it has a lot of responses, so I replied.
Here's your visc calc, go for it.
http://www.widman.biz/English/Calculators/Graph.html
As you see, the 40 weights are the same thickness as 50s are at +/-10c. I'm pointing out how viscs overlap at different temps. Just because you run one visc grade of oil over another doesn't mean your engine will never see the same visc result...at a few degrees apart. Show me some actual numbers of what you consider too thin (when hot) and too thick (when cold). That's useable data, not some half-baked rant.
When I point out examples of thin oils being applied elsewhere in engines, where some would expect heavier oils, that just a for-example. How you apply it is up to you. I don't think this kind of counter point is presented to the group otherwise. imo, any engine showing low OP on 15w-40 is defective. 50 weight should be considered a band-aid or to counter elevated oil temps from high speed service...not idling. I have no doubt your engine oil needs are specific. I actually didn't realize this was the 928 forum, or I would have parsed my early comments accordingly. Still, I think there is a mechanical explanation missing, be it oil pump issues, or even metering issues, which is a known phenomenon.
Here's my call out, if you might be using 20w-50 in cold, at least try 15w-40, it doesn't cost much and is state-of-the art. Then, maybe pull a UOA and go back to 50 weight, pull another UOA and compare. See, the 40 weight IS just as thick as a 50, until it's overly heated. (I hope I'm explaining this properly)
From everything you guys told me, I'd think you'd be excited about a product like Kendall GT-1 Ti. Best of all, it comes in a 20w-50!!!
Although the 10w-40 would be killer in most apps.
Here's some virgin info on the OLD Kendall GT-1 20w-50
I'm not seeing much zink in there.
and very (extremely) low wear result.
A UOA programme from you guys is needed.
Here's your visc calc, go for it.
http://www.widman.biz/English/Calculators/Graph.html
As you see, the 40 weights are the same thickness as 50s are at +/-10c. I'm pointing out how viscs overlap at different temps. Just because you run one visc grade of oil over another doesn't mean your engine will never see the same visc result...at a few degrees apart. Show me some actual numbers of what you consider too thin (when hot) and too thick (when cold). That's useable data, not some half-baked rant.
When I point out examples of thin oils being applied elsewhere in engines, where some would expect heavier oils, that just a for-example. How you apply it is up to you. I don't think this kind of counter point is presented to the group otherwise. imo, any engine showing low OP on 15w-40 is defective. 50 weight should be considered a band-aid or to counter elevated oil temps from high speed service...not idling. I have no doubt your engine oil needs are specific. I actually didn't realize this was the 928 forum, or I would have parsed my early comments accordingly. Still, I think there is a mechanical explanation missing, be it oil pump issues, or even metering issues, which is a known phenomenon.
Here's my call out, if you might be using 20w-50 in cold, at least try 15w-40, it doesn't cost much and is state-of-the art. Then, maybe pull a UOA and go back to 50 weight, pull another UOA and compare. See, the 40 weight IS just as thick as a 50, until it's overly heated. (I hope I'm explaining this properly)
From everything you guys told me, I'd think you'd be excited about a product like Kendall GT-1 Ti. Best of all, it comes in a 20w-50!!!
Although the 10w-40 would be killer in most apps.
Here's some virgin info on the OLD Kendall GT-1 20w-50
I'm not seeing much zink in there.
and very (extremely) low wear result.
A UOA programme from you guys is needed.