You might try putting a check valve in your feed line, forcing the gases to exit the other way.
I once hooked up a lot of small cell in parallel by using manafolds made of 1/2 PVC on top and bottom of the cells. I had trouble with cirulation until I added check valves on each cell's input line.
1991 Plymouth Acclaim 3L V6.
1 dry cells with nineteen 6"x8" 316L ss plates, driven by constant current PWM set at 35 amps (13.3V at PWM). 28% KOH electrolyte. Total measured output 2.5 lpm. Mileage went from 18 to 26 mpg, all city driving (44% increase). EFIE set at .370 and I still need to play with ignition timing.