No not a brag. I haven't done this in a long time. It's really unhealthy but I was trying to get a startup off the ground and became obsessed. Don't recommend it.
I do personally find myself most productive with a cycle of 20 hours awake / 12 hours asleep. Circadian rhythms vary by person.
Unfortunately, the world makes it hard to keep that cycle, and so instead I mostly do 17 hours awake / 7 asleep, which makes me feel constantly tired (though less tired than 16/8 at least).