The Sakae-31 (Ha-315 or Ha-35 mod 31), had it run reliably, would have given the A6M7 a better performance compared to the A6M5c. The intended power was 1360 ps because the rpm was kept at 2700 compared to 3000 for the Homare but that power was never achieved. The water methanol injection was not perfected and there also seem to have been problems with the supercharger (Goodwin and Starkings, page 177). The Sakae-31b actually produced lacked the water injection and returned to the Sakae-21 supercharger, so the A6M7 did not show much gain in performance.