What i am saying on short is, apparently the OP is unhappy with the choice, thinking a 1,7A motor would give him approx double power than the 2.5A motor, which is highly unlikely regardless of what datasheets or ebay says. Besides, the holding torque isnt so relevant do dynamic behavior anyway but thats beyond the point. Then i tried to say that power isnt inherent to the motor max current, but otherwise inherent to driver settings. For example take a nema17, nema23, and nema34 motors, if all are used with same driver and same settings, they will give about same power regardless of being different motors. Because output ultimately depends on what is being put in. Beyond this, in some motors can put more current, in some not so much. Therefore while higher current is likely higher torque, still is not enough to change the motor, would need to change the driver, or at least upper driver setting. Also what he could do in the situation is to use double belt aka MadKite belt mod. The bottom problem is the bed is 4x the size and probably same times more weight than normal. Not in that the motors have too high current rating. Imho the latter is probably more fortunate, at least provides a margin if needed.
I have done the same thing as OP, in the link i gave e.g. 4x bed size, and it has its flaws. Has to be felt in practice to understand. Its much heavier, vibrations make more noise, harder to heat up and wastes so much heat when printing small parts - quite inefficient. Beyond this, about motors in this application, ultimately i think this is due to the construction in which x and y being separate, increase of the bed size means bed is heaviest, which limits both axis. Printer designs like ultimaker which have the x and y together in same constriction (if thats correct english word), i think those models scale up in bed size much better because it doesnt add the bed weight to either x or y - those only add the weight of axis increase and that is likely lesser.
I have done the same thing as OP, in the link i gave e.g. 4x bed size, and it has its flaws. Has to be felt in practice to understand. Its much heavier, vibrations make more noise, harder to heat up and wastes so much heat when printing small parts - quite inefficient. Beyond this, about motors in this application, ultimately i think this is due to the construction in which x and y being separate, increase of the bed size means bed is heaviest, which limits both axis. Printer designs like ultimaker which have the x and y together in same constriction (if thats correct english word), i think those models scale up in bed size much better because it doesnt add the bed weight to either x or y - those only add the weight of axis increase and that is likely lesser.
