This is very interesting,
Royal Purple, AMSOIL XL7500 as well
And:
Chevron Supreme is Synthetic 5W30 is Group IV & V
So there is something to the argument that RP is a blend of PAO + Group III . The exact proportions of which are still an enigma.
Take a look:
http://216.109.117.135/search/cache...7Cy61EJ:www.doa.state.nc.us/PandC/q9150-1.pdf
Royal Purple, AMSOIL XL7500 as well
And:
Chevron Supreme is Synthetic 5W30 is Group IV & V
So there is something to the argument that RP is a blend of PAO + Group III . The exact proportions of which are still an enigma.
Take a look:
http://216.109.117.135/search/cache...7Cy61EJ:www.doa.state.nc.us/PandC/q9150-1.pdf