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01-09-2015, 11:20 AM | #1 |
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Some interesting N54 oil sample results? (GC)
Hi guys,
Now I know this is more-so of a topic for Bobistheoilguy but I figured I would post here, both to get more information about my results and also to show you some interesting results. I'm currently on my second batch of German Castrol (0W-30), this oil sample is from the first German Castrol the car had seen, always on BMW synth (dino) prior to that. A large part of my decision to go with GC was due to the extremely low temperatures we get up here in Alberta during the winter time, the 0 weight helps a lot (from my experience), and PDS info for GC looks very good @ -35c. View post on imgur.com Now I'm a tad concerned here, the oil only had 6500km (~4000 miles) on it, but sheared down to what could be considered a heavy 20 weight, or a very light 30 weight. Viscosity @ 100C cSt is at 12.21 (when new), however it sheared down to 9.85. All of my data looks clean as far as water, fuel, etc. in my oil, and is supplemented with the high flash point. So, considering I drive quite conservatively, always heat my oil to a minimum of 90c (I know ~100c is the goal, but it's almost impossible at -30c). What do you guys think could be causing viscosity to dive so severally? In my mind, the rapid and routine (daily) temperature changes from cold to hot is causing too large of a temperature difference, effectively causing the oil to shear extremely quickly when routinely changing states from -20c/-30c up to 90c/100c. Just to reiterate, I drive very conservatively especially during the winter time, car doesn't see over 3k rpm or a >25% throttle until 80c+. Thanks! |
01-09-2015, 04:31 PM | #2 |
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My knowledge of oil is modest, so grain of salt here.
But it would appear the TBN is still pretty strong, so the detergent pack is still working, and the oil is still doing its' job. The amount of viscosity loss is troubling for sure though.....All of the Blackstone reports i've gotten on my motor show minimal loss of TBN and effective viscosity. Not very helpful, I know
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E88 N54 Alpinweiss/Coral Red/Motiv HTA 3586r Tial .82AR/Other stuff...652WHP
F30 N55 XDrive EBII |
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01-09-2015, 05:11 PM | #3 |
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Not the same engine, however on my S54 I've received the following oil results on cSt @1 00C:
4,296 miles - 16.85 2,801 miles - 17,98 6,551 miles - 18.80 Universal Averages are 15.5-20.6 What I'm saying is, more samples will help define a better baseline. I wouldn't be running around screaming though |
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01-09-2015, 05:14 PM | #4 |
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I wonder if the 0w30 has a lot of viscosity index improvers in it? They are long chains that unwind when they get hot. Unfortunately, that is the first thing to break down in severe conditions and will result in what you are seeing. Will thin out at the hot temp, and be more like the base stock, which may be a 0W20.
The wider the difference between the two numbers, the better chance that it has VII's in it. Maybe switch to a 5W30. A good full synthetic 5W30 will flow pretty well in Canadian winters, and should not have any VII's. |
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