How long can you stay awake with no sleep at all before you become completely delirious?

I'm going on about 50+ hrs w/out right now. I'm not delirious at all. I've noticed my sight is slightly less focused and my thought processes are not flowing as cohesively as normal. Motor functions have a slower response time also, but I do not feel sleepy, just incredibly tired. But, like I mentioned before, no signs of deliri- ****!!! My guitar started talking to me! Okay. Never mind, he's playing with the rocking chair now.