quote:
Originally posted by blueglide88:
OK guys, a newbie here. What does all this mean? What is a good VI number? What is the 100c and 40c index numbers mean? I understand flashpoint and pour, but not anything else on these charts
Welcome aboard.
VI stands for Viscosity Index. Our acronyms are listed here:
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=21;t=000072
There's no such thing as a "good VI number". VI tells us how able an oil is to flow properly with both high and low temperatures. An oil with a very low VI would probably only be a good choice if you were in a place that was warm all the time. An oil with a very high VI would be more likely to flow in your engine well at low temperatures and still be thick enough to protect you at higher temperatures. For the record, oils with a high VI tend to be more expensive than oils with a low VI, but that's only a general rule.
The 100c index tells you how "thick" an oil is at 100 degrees celsius, or 212 fahrenheit.
The 40c index tells you how "thick" an oil is at 40 degrees celsius, or 104 fahrenheit.
If you want to get up to speed quickly, try reading the topics at the Question of the Day forum:
http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=forum;f=21;DaysPrune=1000
Also go to the Bobistheoilguy main page at
http://www.bobistheoilguy.com/ and read all of the topics under General Topics.
If you do that, you'll already be better informed that 97% of Americans are about motor oil.
If you still have a question about engine oil, post it in this forum, and you'll likely get good help understanding whatever questions you have.
