wrote:
>
> 2 banks of 4-cyl almost certainly have much more if not double the
> total friction area compared to a single bank.
> Using less than a litre of additonal oil to cover that extra area looks
> like the oil needs to work harder, meaning their additives would be
> depleted faster (?)
>
> B.

It depends on the driver. Typically a 4 cylinder revs higher and works harder
than a 6 or 8. Higher revs = higher stresses. That's why 4's don't last long
compared to a 6 or 8. Assuming the driver runs the hell out of the 4 trying to
keep up with the 6's and 8's, I would expect a 4 to need much more frequent oil
changes.