Eight Three Suited vs Ace Three Offsuit

At the flop:
Winning 16.48% of the time
Tied 0% of the time
Losing 83.52% of the time

At the Turn:
Winning 22.39% of the time
Tied 0.28% of the time
Losing 77.33% of the time

At the River:
Winning 28.75% of the time(12.14% with trips or better)
Tied 1.65% of the time
Losing 69.6% of the time(4.15% with trips or better)