Oil weights / Cst.

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Hello BITOG my name is Andy. Here is where i am a little confused on oil weights.. lets use a _W-30 weight M1 oil for discussion. In the morning i start my car it is 40*C out using M1 5w-30. On the M1 site it says my Cst is 64.8. and at 100*C the Cst is 11.3. Now lets say i use a 0w-30 M1 it is 40*c out. on the M1 site is says the Cst is 63.1. and at 100*c it is 11. after reading the board for a while and reading post that say "0W-_ oil is better for start up protection because it is thinner than a 5w-_ oil." Is 1.7 Cst on start up really going to help much? yes i understand that the W is "winter blend" so to speak... i have also read on here that an "0w-30 is too thin of an oil on start up and will hurt the engine????" Thus the poster suggested a 10w-30 oil... Or is looking at the Cst not the correct way to judge how an oil will flow in an engine at different temps? KV (kinematic Viscosity) is measured in Cst. rite? Is the 0w-30 or 5w-30 oils different below the 40*C test temp that i am not able to find data on? Thanks
 
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 Originally Posted By: MrBigBlock
Is 1.7 Cst on start up really going to help much? yes i understand that the W is "winter blend" so to speak... i have also read on here that an "0w-30 is too thin of an oil on start up and will hurt the engine????" Thus the poster suggested a 10w-30 oil... Or is looking at the Cst not the correct way to judge how an oil will flow in an engine at different temps? KV (kinematic Viscosity) is measured in Cst. rite? Is the 0w-30 or 5w-30 oils different below the 40*C test temp that i am not able to find data on? Thanks
You are comparing two very like oils, so there is not so much difference. Look at the below zero numbers.
 Quote:
i have also read on here that an "0w-30 is too thin of an oil on start up and will hurt the engine????" Thus the poster suggested a 10w-30 oil...
You may have read that here, but it's total [censored].
 

MrBigBlock

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 Originally Posted By: Pablo
You are comparing two very like oils, so there is not so much difference. Look at the below zero numbers.
 Quote:
i have also read on here that an "0w-30 is too thin of an oil on start up and will hurt the engine????" Thus the poster suggested a 10w-30 oil...
You may have read that here, but it's total [censored].
So why does M1 make a 0w-30 and a 5w30 with such close 40*c numbers? Is there a data sheet that shows below 0* numbers?
 
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 Quote:
In the morning i start my car it is 40*C out
Are you writing this from Death Valley in the summer?
 

MrBigBlock

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 Originally Posted By: XS650
 Quote:
In the morning i start my car it is 40*C out
Are you writing this from Death Valley in the summer?
no i used that as an easy # instead of saying it's 25.5*C out. and guessing the Cst....
 Originally Posted By: Pablo
It's the nature of the beast. Look at Amsoil, 57 vs. 61. But I think you are missing the forest for the trees.....regardless 0W and 5W aren't 40°C derived numbers. http://www.infineum.com/information/api-viscosity-2004.html If Mobil publishes the cold temp numbers they should be on their site.
i used 40*c because its on there website (easy comparison) like i said i don't have the numbers on the Cst lower than 40*c so that's what i used for discussion.
 
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40°C = 104°F, which is closer to 100°C than the -25°C that 10W is tested at or the -35°C that 0W is tested at. The difference in viscosity between 40°C and 100°C is used to determine the viscosity index. As you've identified, the functional difference between 0W, 5W, and 10W when warm isn't significant. The real difference is the viscosity when frigid. Here's the SAE J300 viscosity chart. http://www.infineum.com/information/api_...%20-%202008.pdf Note that any 30 wt tests somewhere between 9.3 and 12.49 centiStokes kinematic viscosity @100°C.
 
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