View Single Post
Old 02-25-2002, 08:29 AM
loubapache loubapache is offline
Registered User
Join Date: Jul 2001
Location: Western Michigan
Posts: 1,080
Oil Research Results

Below are two URLs that link to two tables I compiled by comparing popular motor oil specs.

Popular SJ/SL Oil Information

Popular SJ/CH-4 Oil Information

Once you see the table, the link on the oil's brand and viscosity is to the product specs of the oil's manufacture's Website, from which the numbers below are derived.

Some information about the numbers:

Viscosity Index (VI): It is a measure of the rate of change in kinetic viscosity over a given temperature range (40C and 100C ). Larger number indicates lesser change. Because oil thins out as temperature increases, a oil of higher VI will not thin out as much.

Kinetic Viscosity 40C/100C: This is related to VI and is measured in centistokes (cSt). These numbers are the kinetic viscosity measured at two temperatures. Note the number at higher temperature is lower due to oil thinning. A smaller number at low temperature and a higher number at high temperature are desired. For a 40 weight oil (the higher number after W), the number should be around 15 cSt at 100C and for a 30 weight oil, it should be around 10 cSt at 100C.

Pour Point: Fluidity at low temperatures in degrees Celsius (Fahrenheit). The lower the number, the better it flows at low temperature.

Flash Point: Temperature at which the oil starts to vaporize in degrees Celsius (Fahrenheit). Typically, the engines operates at around 100C, plus or minus 20C. The higher the number, the more stable the oil at high temperatures.

Cold Cranking Viscosity (CPV): This is measured in centipoises (cP). Cold Cranking Viscosity measures the resistance at a certain temperature, typically -15C. However, different manufactures measure at different temperatures that makes this comparison more difficult. In general, a lower number indicates easier cold starting.

Total Base Number (TBN): Indicates stability, engine protection and cleanliness, and performance. Higher numbers are better. In general, oil rated at CG-4 and CH-4 has higher TBN than those only carrying the SJ and SL ratings.

Last edited by loubapache; 03-04-2002 at 02:23 PM.
Reply With Quote