Selenia does not make synthetic oils. They make semy sinth and sell them as synth (Racing 10w60) tha same way that Castrol sells some of its oils as synth (but are basically hidrocracked and not ester or PAO based).
You can't compare oils that are used in car engines and oils for motorbike usage.
SEMI-Synthetic oil has better cling characteristics and meets both needs of the engine hense being the right choice for your car!
Nope mate, you've got it all wrong. The only reason why Alfa recomended (they do not anymore) Selenia semy oils was because Selenia was once a part of FIAT and they only had semy oils to offer. If you don't believe me, check their site out:
Selenia - HISTORY
Now, that they are a part of petronas, Alfa doesn't recomend Selenia anymore, but rather other brands, but that's beside the point. What's important is that there is no reason for someone to use Selenia rather that lets say Castrol, Motul or Elf. All companies have sponsorship deals with oil manufacturers, but that doesn't mean that their oil is the only brand an engine can use.
The most important figures to look for, when comparing diff oil brands, are the HTHS values: the higher the value the better and more expensive the oil. Semy oils' HTHS values are below any minimal fully synth values.
Another thing is the viscositiy: the thicker the oil the longer it takes for it to flow through the engine and the higher the friction which increases the temp. Fully synth oils are 0/5/10...w and semys are 10w and above.
Hope this makes some sense