Chapter 105.5
Questions and answers:
I apologize that I am going too fast and not responding to some questions. Let me stop here and catch up. I am a little unsure how to answer some questions. Several will be answered in later chapters as I have alluded to but I will try better. Forgive me when it comes up again though.
I have written these chapters over the last few months in some Ferrari publications, FerrariChat, Lamborghini-Talk and other areas. The tech chief at Ferrari North America distributed the articles to others. I can reference most of what I have written but it really bogs it down.
Bring me more questions, for now let me start with the last question in 105:
haley10 asked the following:
“AEhaas, is the 10 cst somewhat arbitrary? Can you explain why the LT1, LS1 seem to do better with a 12 cst oil???”
I am not sure what you are asking. I have used 0W-30, 10w30 and straight 30 wt. oils to show that they all have the same viscosity grade when hot yet thicken more after shut-down as the viscosity index decreases. They all have the same viscosity grade at normal operating temperature, approximately 10 cS. I could have used all 40 wt. oils as an example. I am not telling you what wt. you need but rather to use an oil that thickens less after engine shutdown. I do advocate thinner oils though, rather than thicker as most people think.
What makes you say your LS1 does better with a 12 cS operating temperature oil? For me going from 30 to 20 wt. oil in my Ferrari decreased the temperature about 10 F - under the same driving conditions. The oil pressure went down about 5 PSI at around town driving temperatures. There was no penalty in my oil analysis. The car started faster. It may have been a little faster especially when not up to full temperature but that is hard to say for sure - just seat of the pants. I concluded that the thinner wt. oil was therefore better for MY driving situation.
haley10 asked the following:
“Although, 0W is important some engines seem to also like a bit more HT/HS on the top end.”
Mobil 1 0w30 has a HTHS of 2.99, Redline 10w30, perhaps the thickest, is at 3.8. For racing situations using engines with 5 - 6 - 700 BHP I like Redline but is that what we need around town? I do not think so. Again, I ask how one knows that 0.8 more HTHS is “liked” better? I do recommend oils that thicken less after engine shut down to minimize start-up wear. I think this is most important. Here is my evidence from a later chapter:
Effect of Break-In and Operating Conditions on Piston Ring and Cylinder Bore Wear in SI (Spark-Ignition) Engines, Schneider et al:
The rate of wear is much higher within 15-20 minutes of start-up than after reaching normal operating temperature. There was a lot of data but I conclude that the initial start-up time period (first 20 minutes) result is 100 nanometers of wear whereas the steady state wear rate was only 4 nanometers per hour thereafter. (Hence we should be concerned about start-up oil thickness more than running thickness. This justifies the statement that 95 percent of engine wear occurs just after start-up)
haley10 asked the following:
“As long as an oil like GC is 0W, might it not also heat up faster to 12cst than say another 0w30 to 10 cst with a different basestock? Time should also be a factor.”
I have seen this. As an example my neighbor’s Maranello runs Shell Helix Ultra 5W-40 while I use the Mobil 0W-20. He revs it up a bit more than me and gets up to temperature in 10 minutes. I keep the revs down a little and it takes me 15 minutes to heat up. The whole time though my oil is thin enough to rev it up from the start with minimal penalty. It does not worry me that I heat up slower. I actually think it is a good thing.
Synthetic oils have lower internal resistance. If we compare a mineral and synthetic of the same wt. we will find that the synthetic will heat up slower. Is this bad? I suppose this could be a drawback to synthetic oils but I do not think so.
aehaas
Questions and answers:
I apologize that I am going too fast and not responding to some questions. Let me stop here and catch up. I am a little unsure how to answer some questions. Several will be answered in later chapters as I have alluded to but I will try better. Forgive me when it comes up again though.
I have written these chapters over the last few months in some Ferrari publications, FerrariChat, Lamborghini-Talk and other areas. The tech chief at Ferrari North America distributed the articles to others. I can reference most of what I have written but it really bogs it down.
Bring me more questions, for now let me start with the last question in 105:
haley10 asked the following:
“AEhaas, is the 10 cst somewhat arbitrary? Can you explain why the LT1, LS1 seem to do better with a 12 cst oil???”
I am not sure what you are asking. I have used 0W-30, 10w30 and straight 30 wt. oils to show that they all have the same viscosity grade when hot yet thicken more after shut-down as the viscosity index decreases. They all have the same viscosity grade at normal operating temperature, approximately 10 cS. I could have used all 40 wt. oils as an example. I am not telling you what wt. you need but rather to use an oil that thickens less after engine shutdown. I do advocate thinner oils though, rather than thicker as most people think.
What makes you say your LS1 does better with a 12 cS operating temperature oil? For me going from 30 to 20 wt. oil in my Ferrari decreased the temperature about 10 F - under the same driving conditions. The oil pressure went down about 5 PSI at around town driving temperatures. There was no penalty in my oil analysis. The car started faster. It may have been a little faster especially when not up to full temperature but that is hard to say for sure - just seat of the pants. I concluded that the thinner wt. oil was therefore better for MY driving situation.
haley10 asked the following:
“Although, 0W is important some engines seem to also like a bit more HT/HS on the top end.”
Mobil 1 0w30 has a HTHS of 2.99, Redline 10w30, perhaps the thickest, is at 3.8. For racing situations using engines with 5 - 6 - 700 BHP I like Redline but is that what we need around town? I do not think so. Again, I ask how one knows that 0.8 more HTHS is “liked” better? I do recommend oils that thicken less after engine shut down to minimize start-up wear. I think this is most important. Here is my evidence from a later chapter:
Effect of Break-In and Operating Conditions on Piston Ring and Cylinder Bore Wear in SI (Spark-Ignition) Engines, Schneider et al:
The rate of wear is much higher within 15-20 minutes of start-up than after reaching normal operating temperature. There was a lot of data but I conclude that the initial start-up time period (first 20 minutes) result is 100 nanometers of wear whereas the steady state wear rate was only 4 nanometers per hour thereafter. (Hence we should be concerned about start-up oil thickness more than running thickness. This justifies the statement that 95 percent of engine wear occurs just after start-up)
haley10 asked the following:
“As long as an oil like GC is 0W, might it not also heat up faster to 12cst than say another 0w30 to 10 cst with a different basestock? Time should also be a factor.”
I have seen this. As an example my neighbor’s Maranello runs Shell Helix Ultra 5W-40 while I use the Mobil 0W-20. He revs it up a bit more than me and gets up to temperature in 10 minutes. I keep the revs down a little and it takes me 15 minutes to heat up. The whole time though my oil is thin enough to rev it up from the start with minimal penalty. It does not worry me that I heat up slower. I actually think it is a good thing.
Synthetic oils have lower internal resistance. If we compare a mineral and synthetic of the same wt. we will find that the synthetic will heat up slower. Is this bad? I suppose this could be a drawback to synthetic oils but I do not think so.
aehaas
