Quote:
Originally Posted by tofurun
Well... This is about as basic as it gets. I have been reading exactly "what" oil means and what the numbers mean. I tend to agree with what a lot of the descriptions say about people really not fully understanding what the numbers are on oil.  . Mostly because I had no idea myself (the book says use this so i use it). There I said it I DONT KNOW. well I did my research and am trying to fully understand all of it.
I know people are running different oil weights for things like oil coolers and turbos. BUT WHY. why do this. Turbos get oil hotter? Ok so use a thicker oil? well what about the engine specs from Toyota/Subaru? They say run 0w-20. now we have a oil cooler/turbo and we are running 0w-30. So we are increasing the Hot viscosity of the oil. Idk maybe I have been reading this explanations wrong. Heck I may be making it way more complicated than it really is. I am not asking what I should be running (yet). I am trying to understand the entire thing.
It may just be me but i think this would be a great write up for this section of the forum as a Sticky. Not trying to get flamed just trying to fully understand it. |
Have a look here for basic info on oil
http://www.pqiamerica.com/apiserviceclass.htm
have a read of this link , towards the end their some links on oil pressure vs temp .
http://www.ft86club.com/forums/showthread.php?t=81493
very rough giude
If your car is fairly stock and you just drive on the street in a cold to mild climate then just stick with the 0W20 synthetic as per manufactures recommendations for car.
If you drive the car hard or track car in warm to hot climates (ambient well over 30C and never gets below 0C) then probably a 5W30 or even 10W30 is better suited especially if you not running any form of oil cooler.
If you run an oil cooler and your keeping your oil temps below 115 C at all times then you can probably go back to 0W20, if your seeing greater than 120 C then either get a bigger/better oil cooler or run a slightly thicker oil like 5W30.
Its always better to keep the oil temps under control than to run really thick oils
modern synthetic oils dont break down till over 150C, its not generally the oil breaking down you need to worry about its the oil pressure dropping due oil thinning at high temps.
You rearly need to monitor your oil temps to determine the most suitable oil for your conditions and driving