Has been stated on BITOG a number of times, and only last couple of days has it really cemented itself to me.
Two base-stocks, same KV100, same VI (so therefore same KV40)...the two determinants on a Product Data Sheet (or MSDS for some)...two data points and the slope of a line between them.
And very very different behaviours below freezing temperatures.
Scaling off the pic, the GrIII looks to be 60,000cp at -35C which is the limit for 5W...5C to the left (-40C), 60,000cp is the limit for 0W.
Plug the KV40 and 100 into the widman site, and you get
for both...clearly not what's really happening.
(Note different units, poise and stokes)
Two base-stocks, same KV100, same VI (so therefore same KV40)...the two determinants on a Product Data Sheet (or MSDS for some)...two data points and the slope of a line between them.
And very very different behaviours below freezing temperatures.
Scaling off the pic, the GrIII looks to be 60,000cp at -35C which is the limit for 5W...5C to the left (-40C), 60,000cp is the limit for 0W.
Plug the KV40 and 100 into the widman site, and you get
for both...clearly not what's really happening.
(Note different units, poise and stokes)