Help with Braking

Well we were running Le Mans last night and my problems with braking showed up worse than normal.

I cant seem to get a feel for braking with the pad so im still using brake line and ABS.  However, coming into every corner im not sure whats going to happen, sometimes i brake and stop way too early, othertimes i slid straight past the corner.  As a starting spot i always try to hit the brakes just as i hit the red arrows in the line but on the same corner with the same speeds its still hit and miss whats happening.  

All that tells me is that its me causing the problem.  Trouble is, i dont know what it is im doing wrong