My dealer used Mobil 1, strange?
06-01-2007, 09:06 PM
#41
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it still doesn't explain the strange corelation of iron ppm in used oil and iron wear
explain that to me. your results show the castrol at 46ppm, the mobil 1 at 37. but, the mobil 1 iron wear number(as measured?) is higher. that doesn't mesh.
06-01-2007, 09:08 PM
#42
Some "high quality" synthetic oils will harm your engines
I know you don't want to believe it, but its true. There are three basic components to oils that we use.
Base oils
Detergent additive package
Friction modification and extreme pressure additives
There are dyno oils that flat outperform synthetic oils in wear control because they use better friction modifiers and extreme pressure additives. Just because an oil is a full PAO or Ester synthetic does not necessarily make it a good oil for the application. Both may have tremendous characteristics over temperature, but both need to be modified by additive packages to work. Some oil companies seem to do a good job at this. Others do not. These days it is the additives that make a good oil good.
If I were to recommend any off the shelf oil to you, it would be Amsoil Euro 5W-40. Of all the off the shelf oils that we've measured, it performs measurably better than the rest in this engine.
Base oils
Detergent additive package
Friction modification and extreme pressure additives
There are dyno oils that flat outperform synthetic oils in wear control because they use better friction modifiers and extreme pressure additives. Just because an oil is a full PAO or Ester synthetic does not necessarily make it a good oil for the application. Both may have tremendous characteristics over temperature, but both need to be modified by additive packages to work. Some oil companies seem to do a good job at this. Others do not. These days it is the additives that make a good oil good.
If I were to recommend any off the shelf oil to you, it would be Amsoil Euro 5W-40. Of all the off the shelf oils that we've measured, it performs measurably better than the rest in this engine.
06-01-2007, 09:18 PM
#43
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forget your formula
the iron ppm should be a cumulative thing. it's not going to diminish in the oil that's presently in the engine. where would it go?
the mileage difference on the oil is incidental. what you should be concerned with in an OIL ANALYSIS is what's in the used oil, contaminants, metals, etc. the fact that you have a higher wear number(however derived) with less iron ppm tells me that the formula you have chosen to apply is flawed.
it's not a straight correlation, Scott. you cannot possibly say that 37 iron ppm at 4500 miles translates to x amount of wear. the 'wear' rate could diminish(or increase) during the life of the oil. there could be something else going on in the engine, independant from the oil...a bearing suddenly wearing, acids from prior miles adding more iron ppm over time, engine load or higher sustained rpm, etc.
this is what i mean. you are not going to be able to apply meager formulas of your choosing and arrive at any worthwhile conclusions. it's not gonna happen. not the way you are doing it.
the mileage difference on the oil is incidental. what you should be concerned with in an OIL ANALYSIS is what's in the used oil, contaminants, metals, etc. the fact that you have a higher wear number(however derived) with less iron ppm tells me that the formula you have chosen to apply is flawed.
it's not a straight correlation, Scott. you cannot possibly say that 37 iron ppm at 4500 miles translates to x amount of wear. the 'wear' rate could diminish(or increase) during the life of the oil. there could be something else going on in the engine, independant from the oil...a bearing suddenly wearing, acids from prior miles adding more iron ppm over time, engine load or higher sustained rpm, etc.
this is what i mean. you are not going to be able to apply meager formulas of your choosing and arrive at any worthwhile conclusions. it's not gonna happen. not the way you are doing it.
06-01-2007, 09:29 PM
#46
Re: it still doesn't explain the strange corelation of iron ppm in used oil and iron wear
46 parts per million in the oil were shaved off components of the engine after 7000 miles. The wear rate per 1000 miles is therefore 6.6 parts per million for Castrol
37 parts per million in the oil were shaved off the components of the engine after 4500 miles. The wear rate per 1000 miles is therefore 8.2 parts per million for Mobil 1.
If the wear rate for M1 were constant, we would expect the oil to measure 57 ppm if the oil were kept in for 7000 miles like the castrol was.
To put this in a different perspective, we can compute the amount wear particles in the total volume of oil in this engine based on that measurement, and determine the total weight of the metal in the oil.
Density of oil = .877 g/cc
Engine oil capacity 10L
total weight of oil = 8770 g
Total iron in oil measured with 37 ppm Iron
iron/oil = 37 ppm
iron = oil weight x 37ppm
iron = 8770g x .000037 = .324 grams of iron removed from something in the engine.
We can also compute the volume of iron that was removed.
Iron density = 7.86 g/cc
.324 g of iron/ 7.86 g/cc = .041 cc of iron removed in 4500 miles.
If these rates continued for 50K miles we'd expect to see 3.6 grams of iron worn from the engine internals, removing 0.456 cc's of metal.
This is problematic in an Aluminium block engine with hard silicon cylinder walls. We are seeing iron wear at the levels of iron block or iron sleeved cylinders. What we do not know is where the iron is being removed from, although we can determine this if we know the composition in the alloys of different bearings in the engine. However, that iron is coming from somewhere, and is causing increased clearances somewhere in a high performance engine that spins at 8K rpm. It could be in the cams, the rocker arms, the lifters, or the cam chain. It is probably not in the main bearings, since there would be other metals present in the analysis that would be present along with iron.
If we knew which specific component was the predominant contributor to wear, we could compute the rate of tolerance increase over time, and determine when that component is out of spec.
37 parts per million in the oil were shaved off the components of the engine after 4500 miles. The wear rate per 1000 miles is therefore 8.2 parts per million for Mobil 1.
If the wear rate for M1 were constant, we would expect the oil to measure 57 ppm if the oil were kept in for 7000 miles like the castrol was.
To put this in a different perspective, we can compute the amount wear particles in the total volume of oil in this engine based on that measurement, and determine the total weight of the metal in the oil.
Density of oil = .877 g/cc
Engine oil capacity 10L
total weight of oil = 8770 g
Total iron in oil measured with 37 ppm Iron
iron/oil = 37 ppm
iron = oil weight x 37ppm
iron = 8770g x .000037 = .324 grams of iron removed from something in the engine.
We can also compute the volume of iron that was removed.
Iron density = 7.86 g/cc
.324 g of iron/ 7.86 g/cc = .041 cc of iron removed in 4500 miles.
If these rates continued for 50K miles we'd expect to see 3.6 grams of iron worn from the engine internals, removing 0.456 cc's of metal.
This is problematic in an Aluminium block engine with hard silicon cylinder walls. We are seeing iron wear at the levels of iron block or iron sleeved cylinders. What we do not know is where the iron is being removed from, although we can determine this if we know the composition in the alloys of different bearings in the engine. However, that iron is coming from somewhere, and is causing increased clearances somewhere in a high performance engine that spins at 8K rpm. It could be in the cams, the rocker arms, the lifters, or the cam chain. It is probably not in the main bearings, since there would be other metals present in the analysis that would be present along with iron.
If we knew which specific component was the predominant contributor to wear, we could compute the rate of tolerance increase over time, and determine when that component is out of spec.
06-01-2007, 09:33 PM
#48
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gee, I don't know...am I reading correctly that he is doing it at a loss compared to his corp rate?
if that's what you meant to write, that means he's losing money on the deal. allegedly.
06-01-2007, 09:40 PM
#50
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is this one engine where you're comparing the mobil 1 and Castrol
for ppm and total wear? same climate?... same time of year?... same cold start pattern and frequency? if not, you can toss those numbers and calculations right now. how can you be missing this most obvious of things?