From Shoryuken Wiki, Marvel vs. Capcom 3 Strategy and More!
With Super Art 2 (Shinshoryuken) it is possible for Ryu to do 100% damage if he has his opponent cornered. This is one way to achieve it.
Jump-in fierce, standing fierce, fierce shoryuken xx shinshoryuken, jumping fierce x n, (dizzy) jump-in fierce, standing fierce, fierce shoryuken.
As long as the first jumping fierce after the shinshoryuken dizzies, the rest should work. This particular combo will not work on characters with large stun meters, including but not limited to, Alex and Dudley.