the 5W-20 testing and discussions have had me wandering and looking.
http://www.functionalproducts.com/Catalogs/Solid_VII_Products.pdf
was interesting (P4) as it had a comparison between the basestock ISO rating, and the VII requirement to achieve 5W-30, 10W-30, and 10W-40 lubricants (note had disclaimers re detergency adds).
Example 5W-30, 10W-30, and 10W-40 lubricants, start with ISO 22, 32, and 32 oils to begin with, and those with the widest spread use approximately twice the VII of the one in the middle...
http://www.aftonchemical.com/ProductDataSheets/Engine Oil/HiTEC-5751_PDS.pdf (P2)
Has VII percentage (typically) for
5W-30 at 8.0%
10W-30 at 5.8%
10W-40 at 11.8%
15W-40 at 5.5%
20W-50 at 5.5%
Similar ratios, although the first was solid polymer, the latter pre-diluted.
Read with the first reference, there are steps in basestocks, within the grade, to meet the "W" rating.
http://www.aftonchemical.com/ProductDataSheets/Lubricant Components/HiTEC-5710_PDS.pdf
and
http://www.caltex.com.au/FPL PDS/Rando HD.pdf
provide food for thought...(only chose Rando, as Regal doesn't list an ISO 22)
http://www.functionalproducts.com/Catalogs/Solid_VII_Products.pdf
was interesting (P4) as it had a comparison between the basestock ISO rating, and the VII requirement to achieve 5W-30, 10W-30, and 10W-40 lubricants (note had disclaimers re detergency adds).
Example 5W-30, 10W-30, and 10W-40 lubricants, start with ISO 22, 32, and 32 oils to begin with, and those with the widest spread use approximately twice the VII of the one in the middle...
http://www.aftonchemical.com/ProductDataSheets/Engine Oil/HiTEC-5751_PDS.pdf (P2)
Has VII percentage (typically) for
5W-30 at 8.0%
10W-30 at 5.8%
10W-40 at 11.8%
15W-40 at 5.5%
20W-50 at 5.5%
Similar ratios, although the first was solid polymer, the latter pre-diluted.
Read with the first reference, there are steps in basestocks, within the grade, to meet the "W" rating.
http://www.aftonchemical.com/ProductDataSheets/Lubricant Components/HiTEC-5710_PDS.pdf
and
http://www.caltex.com.au/FPL PDS/Rando HD.pdf
provide food for thought...(only chose Rando, as Regal doesn't list an ISO 22)