dail in #???

I was just curious... what exactly is a dail in number. I know its for when u go racing but what is it. My friend told me that it goes according to what u ran or what u toped out at. But i dont get it cause i saw a Z/28 with 207 written all over it.

207 was the check-in number.

If you are bracket racing, then you dial-in.
You guess what you will run. From the time the light turns green to the time you cross the line. Then write it on your window. If you are closer to your number without going over (calling breaking out) you win the race and advance, even if he was faster.

I have never bracket raced. I am not consistent enough yet.
So the finer points of bracket racing have been left out.

ok so before my run do they check me in. Is that when they write the number on y window???

I suppose.
Like I said....I have never done it.