You can't measure it in number of beers - it depends on all sorts of factors.
However, for future reference, I believe it's 0.05% blood alcohol, which is similar to most of Europe. That is, two pints is pretty much guaranteed to put you over the limit. Bear in mind also that 330ml of beer will seriously impair your driving ability, so even if they "allow" you to do that back home, it's really not a great idea.
Don't take the risk ... please. Not on Taiwan's roads, especially, and not on a scooter. Take a taxi and enjoy yourself properly