Differences in Racing oil vs Street Oil ...a must read

Great link (below) on a breakdown/definitions of oil:

There are three parts to the SAE viscosity grade. The last number (20, 30, 40, etc.) defines the “major” grade. It is determined by the oil’s measured viscosity at 212°F (100°C) and is the most important part of the viscosity grade. It should be considered the operating, or effective viscosity grade of the oil. The “W” stands for “winter”, and not “weight” as is commonly believed; and the first number combined with the W is the “winter grade”. The winter grade of a multi-viscosity oil is determined by two parameters: the Cold Cranking Viscosity; and the Pumping Viscosity. These viscosities are defined as maximum viscosity values at various sub-zero temperatures.


http://www.enginelabs.com/engine-te...racing-oil-vs-street-oil-know-the-differences



Learned alot from this read. Thanks Jimjimjimmy...