You might want to check the oil manufactures website and look at the product data sheet. You don't say what vehicle/engine but, a 20w50 oil is not usually used in any modern vehicle. I would imagine that start up wear would be bad at temps below 30 or 40F.
thanks for the info. I will be trying this in an air cooled single cylinder motorcycle. I never ride if its colder than 40F out. Kendall GT1 20w50 it has better ZDDP levels than Yamalube, Suzuki,Kawichem, or Honda GN4 at half the price.