02 Miata, 10043, 125k total, M1 0w20 vs 0w40

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springdale, ar
a chance to compare M1 0w40 with 0w20. the latter had 1 quart of makeup and was a qt low when the oil was changed and the sample taken. the 0w40 had a 1/4 qt of makeup. doesn't look like the lighter vis had any effect on wear at all. TBN was very good for an oil that isn't considered a long life oil.
 Code:
OIL             M1 0w20  M1 0w40  
MILES IN USE    10046    9892    
MILES           125.7k   115.7k   
SAMPLE TAKEN       

ALUMINUM        4        3        
CHROMIUM        1        2        
IRON            23       23       
COPPER          3        5       
LEAD            1        1       
TIN             0        0        
MOLYBDENUM      101      92       
NICKEL          0        0        
MANGANESE       0        0        
SILVER          0        0        
TITANIUM        0        0        
POTASSIUM       2        2       
BORON           52       114       
SILICON         21       18        
SODIUM          7        7       
CALCIUM         2434     3049     
MAGNESIUM       13       18      
PHOSPHORUS      619      878      
ZINC            768      1117     
BARIUM          0        0
     
INSOLUBLES      0.4      0.5      
WATER           0        0        
FLASHPOINT ºF   400      385      
SUS VIS 210ºF   53.5     71.2     
cSt @ 212ºF     12.11    12.33
TBN              2.5      2.0
 
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 Originally Posted By: cheetahdriver
....doesn't look like the lighter vis had any effect on wear at all.
That's because they are the same viscosity!
 Quote:
cSt @ 212ºF 12.11 12.33
Why is the 0W-20 so viscous? Typo?
 
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 Originally Posted By: Pablo
 Originally Posted By: cheetahdriver
....doesn't look like the lighter vis had any effect on wear at all.
That's because they are the same viscosity!
 Quote:
cSt @ 212ºF 12.11 12.33
Why is the 0W-20 so viscous? Typo?
Pablo, Can you explain the different range of numbers for the different viscosity grades. Say start at 20wt up through 50wt. Thanks tig1
 
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There's a chart on the homepage if you are interested... 20W 5.6 - 9.29 30W 9.3 - 12.49 40W 12.5 - 16.29 50W 16.3 - 21.89
 
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 Originally Posted By: zulu
There's a chart on the homepage if you are interested... 20W 5.6 - 9.29 30W 9.3 - 12.49 40W 12.5 - 16.29 50W 16.3 - 21.89
Thanks for finding that. tig1
 
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 Originally Posted By: Pablo
 Originally Posted By: buster
Looks good but the 20 grade is now a 30 grade.
The 40 is now a 30!!
Will either one have any bearing over wear. If so can you explain?
 

cheetahdriver

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Messages
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Location
springdale, ar
color me WAAAY embarrassed. i felt so good about adding the TBN to the column (the original i worked off of didn't have it) that i totally bitbarf'd the vis. corrected
 Code:
OIL             M1 0w20  M1 0w40  
MILES IN USE    10046    9892    
MILES           125.7k   115.7k   
SAMPLE TAKEN       

ALUMINUM        4        3        
CHROMIUM        1        2        
IRON            23       23       
COPPER          3        5       
LEAD            1        1       
TIN             0        0        
MOLYBDENUM      101      92       
NICKEL          0        0        
MANGANESE       0        0        
SILVER          0        0        
TITANIUM        0        0        
POTASSIUM       2        2       
BORON           52       114       
SILICON         21       18        
SODIUM          7        7       
CALCIUM         2434     3049     
MAGNESIUM       13       18      
PHOSPHORUS      619      878      
ZINC            768      1117     
BARIUM          0        0
     
INSOLUBLES      0.4      0.5      
WATER           0        0        
FLASHPOINT ºF   400      385      
SUS VIS 210ºF   53.5     71.2     
cSt @ 212ºF     8.34     13.26
TBN             2.5      2.0

 

cheetahdriver

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springdale, ar
this is what is so shocking to me (now that we have the viscosity mistake out of the way). i have always considered M1 0w40 to be one of the best oils made, yet the 0w20 not only matched or beat the wear metals, but also had a better TBN ( the qt add at 5k undoubtedly helped). while i know OA isn't the final word in the relative merits of oil, the 0w20 also was more drivable in a low hp sports car. in this car at least, i would have to wonder what the reason would be to go back to 0w40, instead of if i should stay with the 0w20. surprisingly fine performance...
 
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Actually, I think that is Springdale, Arkansas. Mobil 1 0W-40 works great in cars it is spec'd for. Doesn't the 02 Miata recommend a 5W-30 oil? Try the Mobil 1 0W-30 and see what happens. I bet your oil consumption will go down.
 
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Considering the consumption and the cost of M1, the 0w40 was probably more cost effective. Was there any difference in mileage? That would of course figure into the determination as to final cost. Regardless, nice OCI, nice engine.
 

cheetahdriver

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springdale, ar
johnny, well, that is an interesting question. in the US manual they want you to use ONLY 5w30 (5w20 on the post 05 model year, different engine). several of us on miata.net went to the AUS miata clubs, and got a copy of the Aussie oil viscosity recommendations. while we figured they would be untainted by CAFE regs, i had not figured on the Aussie propensity for heavy oils. in any event here it is, AUS oil vis chart as you can see, there is a wide variation of oils that the Australians can use, the 20wt oils are right in the thick of it. the real question i want to know is why are 20w20 (there IS such a thing???) and straight 20wt only good to 100F, while 5w20 is good to ~115F? inquiring minds want to know... of course, all of this is for dino, so synthetics should do better.
 
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