View Poll Results: What viscosity oil do you use?
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The Oil Viscosity Poll
07-25-2007, 11:39 AM
#91
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What happens between cold startup temp and full temp?
How long does the average street car take on a 70 degree day to heat up the oil to 100 degree celsius (the temp the higher number is rated for per a few sites I found).
928's are not "average" with almost 10 quarts in the sump. Even on a warm afternoon it's going to take a while to heat up that much oil.
Last night I was driving around my Audi for over an hour of city traffic driving. I pulled into the garage, and within 5 minutes had the drain plug out (no need to lift this car for an oil change). The oil was hot, but not so much I couldn't keep my hand in it (dropped the drain plug). There is no way this oil was anywhere near 100 degrees celsius.
I had 5w-50 Synthetic in this car, lets pretend the oil was 150 degrees celsius coming out of the sump. What weight is this oil at this temperature?
Heinrich,
That could be, but this is in 4 differen manuals I have ranging over a 15 year period.
I was sent this link via e-mail by a Rennlister:
http://www.upmpg.com/tech_articles/m...ity/index.html
In response to my question about what is stated in the manual, yet another Rennlister sent me this:
How long does the average street car take on a 70 degree day to heat up the oil to 100 degree celsius (the temp the higher number is rated for per a few sites I found).
928's are not "average" with almost 10 quarts in the sump. Even on a warm afternoon it's going to take a while to heat up that much oil.
Last night I was driving around my Audi for over an hour of city traffic driving. I pulled into the garage, and within 5 minutes had the drain plug out (no need to lift this car for an oil change). The oil was hot, but not so much I couldn't keep my hand in it (dropped the drain plug). There is no way this oil was anywhere near 100 degrees celsius.
I had 5w-50 Synthetic in this car, lets pretend the oil was 150 degrees celsius coming out of the sump. What weight is this oil at this temperature?
Originally Posted by heinrich
Hacker I think that manual info is incorrect. From the API website (suipports our understanding):
That could be, but this is in 4 differen manuals I have ranging over a 15 year period.
I was sent this link via e-mail by a Rennlister:
http://www.upmpg.com/tech_articles/m...ity/index.html
In response to my question about what is stated in the manual, yet another Rennlister sent me this:
More viscosity improvers added to the oil will lower the w number.
The 10w40 will have more viscosity improvers in it than the 20w40.
The link that Andrew provided talks about the viscosity improvers
shearing under high heat, with the result being insufficient
protection for the engine. More viscosity improvers to give a wide
viscosity span, like the 10w40, means more of that shearing than with
less viscosity improvers, like the 20w40.
That link also mentions that synthetic oils don't require the
viscosity improvers like the conventional oils do. Because of that,
they aren't affected by that shearing. Depending on the age of the
owners manual, what oils were available at that time, and whether
synthetic or conventional oil was specified, there can be differences
because of that. When Audi says not to use a 10w40 above 80 degrees,
I'd guess they're talking about a conventional oil 10w40.
One of the old Porsche approved oils lists differentiated between
conventional oils and synthetic oils. Even though two oils on the
list would both be the same viscosity rating, the conventional oil
would only be approved up to some temperature, and the synthetic oil
would be approved up to a higher temperature, or all the way up to
the maximum temperature that the chart would go up to. So basically
something like a 10w40 conventional oil is not the same as a 10w40
synthetic oil would be. The 10w40 synthetic would be approved up to a
significantly higher temperature than the 10w40 conventional oil
The 10w40 will have more viscosity improvers in it than the 20w40.
The link that Andrew provided talks about the viscosity improvers
shearing under high heat, with the result being insufficient
protection for the engine. More viscosity improvers to give a wide
viscosity span, like the 10w40, means more of that shearing than with
less viscosity improvers, like the 20w40.
That link also mentions that synthetic oils don't require the
viscosity improvers like the conventional oils do. Because of that,
they aren't affected by that shearing. Depending on the age of the
owners manual, what oils were available at that time, and whether
synthetic or conventional oil was specified, there can be differences
because of that. When Audi says not to use a 10w40 above 80 degrees,
I'd guess they're talking about a conventional oil 10w40.
One of the old Porsche approved oils lists differentiated between
conventional oils and synthetic oils. Even though two oils on the
list would both be the same viscosity rating, the conventional oil
would only be approved up to some temperature, and the synthetic oil
would be approved up to a higher temperature, or all the way up to
the maximum temperature that the chart would go up to. So basically
something like a 10w40 conventional oil is not the same as a 10w40
synthetic oil would be. The 10w40 synthetic would be approved up to a
significantly higher temperature than the 10w40 conventional oil
07-25-2007, 09:43 PM
#92
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In case you guys haven't see it, yet: There is a cool new product available now that significantly prolongs the life of your engine oil. Check this out:
http://kalecoauto.com/index.php?main...&products_id=8
http://kalecoauto.com/index.php?main...&products_id=8
07-25-2007, 10:02 PM
#94
Administrator - "Tyson"
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Originally Posted by Nicole
In case you guys haven't see it, yet: There is a cool new product available now that significantly prolongs the life of your engine oil. Check this out:
http://kalecoauto.com/index.php?main...&products_id=8
http://kalecoauto.com/index.php?main...&products_id=8
I forgot about that site!
07-25-2007, 10:20 PM
#95
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Originally Posted by Big Dave
I'll watch the gauge carefully. Aside from my current repair effort I've never had pressure issues, but it's always been conventional oil.
The fact that Doug Hillary is using 5w40 helped my decision (no offense Chaad...I see you use it, too).
The fact that Doug Hillary is using 5w40 helped my decision (no offense Chaad...I see you use it, too).
07-25-2007, 10:44 PM
#96
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Originally Posted by FlyingDog
I had no pressure problems with the same oil. After I pulled my engine I used Delvac 1300 15W40 instead of the 5W40 just because that's what was available.
Friend of mine is the head diesel engineer for Volvo Penta of Carver Boats. They will only use conventional diesel oils in their engines. Delvac 1300 is his oil of choice.
FWIW Tim Murphy and Todd's 600+ hp 928 engines run only conventional non synthetic motor oil.
07-25-2007, 10:59 PM
#97
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I know it's conventional. Delvac 1300 has an amazing reputation among the diesel owners and engineers I know.
I'm surprised Volvo doesn't use synthetic. Synthetic seems to be the obvious choice for turbos.
I'm surprised Volvo doesn't use synthetic. Synthetic seems to be the obvious choice for turbos.
07-26-2007, 01:54 PM
#98
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Of those using the red line product on the track are you using the Race oil or the street oil.. It's my understanding that the Race Oil has little detergent and they do not recommend it for street use.
I am making a change from my Castrol 5w50 after seeing oil pressure drops at the last DE.....whether it was the oil or whether I am just progressing as a driver and uncovering the sump I don't know, but the oil is certianly one variable that I can control and go with what has been proven.
My initial reason for the 5w50 was to just have one oil on hand for the 928 and 911. (Doug Hillary did give me his blessing as this being good choice)
Any observations.....I can order Red line through a local shop and not have to pay all of the shipping costs. (There are no Amsoil dealers in the area Mark. )
Ken
I am making a change from my Castrol 5w50 after seeing oil pressure drops at the last DE.....whether it was the oil or whether I am just progressing as a driver and uncovering the sump I don't know, but the oil is certianly one variable that I can control and go with what has been proven.
My initial reason for the 5w50 was to just have one oil on hand for the 928 and 911. (Doug Hillary did give me his blessing as this being good choice)
Any observations.....I can order Red line through a local shop and not have to pay all of the shipping costs. (There are no Amsoil dealers in the area Mark. )
Ken
07-26-2007, 02:56 PM
#99
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Vlocity,
I've been a Castrol Syntec user for many, many years. Last two oil changes (one with the VW, one with the Audi) I was not impressed.
The lifters on my Audi started to play jingle bells after only 2,500 miles (went away after an oil change). The oil that came out of my Scirocco after 4,000ish miles was sludge. Literally, rubbing it between my fingers it felt like water.
After sharing this "story" with a few local friends I doscovered two well known shops around here that refuse to use it anymore. Not sure what changed, if anything.
I've been a Castrol Syntec user for many, many years. Last two oil changes (one with the VW, one with the Audi) I was not impressed.
The lifters on my Audi started to play jingle bells after only 2,500 miles (went away after an oil change). The oil that came out of my Scirocco after 4,000ish miles was sludge. Literally, rubbing it between my fingers it felt like water.
After sharing this "story" with a few local friends I doscovered two well known shops around here that refuse to use it anymore. Not sure what changed, if anything.
07-26-2007, 06:27 PM
#100
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I've been a Castrol Syntec user for many, many years. Last two oil changes (one with the VW, one with the Audi) I was not impressed.
I will be switching to Red Line or Amsoil. The Delvac looks really good, but I'd like to have a 50 weight for on the track with the SC motor.
Maybe I'll go to Delvac in the 911.
Thanks for the response.
Ken
07-26-2007, 06:31 PM
#101
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Interesting. I bought my car with Swepco gear oil. It would not shift into 2nd. I drained and replaced with Mobil One Synth Gear Oil. All issues were gone and shifting was normal. Recently it was time to replace the oil. Shifting was crisp and smooth. I put NEW Mobil One Synth gear oil, same weight, in and now shifting is clearly slower. So ... I know they changed formula of the Mobil One gear oil .... maybe the same with new oil from Castrol, and engine oils?
