OK just to clarify as the links copied from the old thread didn't work this is the thread

https://www.crossfireforum.org/forum...oved-oils.html

and the other bit shows the power of respective engines as a brake horse power per litre, the higher the more stressed and the requirement for better lubrication especially as temperatures go extreme (hot not really issue here as hot starts at +32 degrees C)
When you look at some of the motorbike eg Fireblade the BHP/Lt = 178 then you really need high quality lubrication and regular short oil changes.

The old rally car I ran had around 115 BHP/Lt and ran on Duckhams Q20/50 long before synthetics were around - as I recall the idea behind synthetics was to extend oil changes primarily on diesels which had 3000 between changes and now are typically 20,000 on synthetic