need tank about 22 to 24oz lot of thirsty for 91 VAC Depend on your size SG rigger small tank only 20oz? " not finish to win or miss enough 1-2 more laps " Good Luck!
The SG 90 will hold enough for a VAC 91. If it is an SGX it will hold more than enough. If you don't run all of your laps in lane 8 and fire up the engine imeadiately, 16 oz. is even enough.