to quote one of my prior post
"normally V1 should not be tampered with unless the AFM allows a V1 range either V1 min. For field length limitations (such as when a clearway exist that can be overflown within the TODA and the aircraft meets appropriate screen heights for rwy conditions -ASDA v. ASDR- and obstacle clearance on the first and second segments of the net flight path. and everything is scheduled in the perf. tables or afm or the perf pages of the afm or the FMC. and nothing is overtly limiting ). or pick a V1 max for wat limited or obstacle limited departures where you want to stop as late as possible where field length is obviously not limiting and AOTA)) and as y'all said V1 can never be less than Vmcg cuz you'd drift of the side at high power".
with a small digression added
