About 2 minutes for a large bottle.

And yes only on full throttle.

If used on a big turbo then it makes a lot of sense doing as stav says and using it only for "anti lag", plus then when it runs out your car is still quick, just less responsive.

Amazes me that anyone who spends a lot of money on their YB doesnt have nitrous, I really cant imagine why it wouldnt be wanted, people say stupid stuff like "it runs out" but when it runs out its only the same as not having it, so why have it none of the time when you can have the option?