To see the max speed at which you can print you need the volumetric speed at which you can print.
The max volume for the Dragon w/ SUNLU Red PLA is 20mm^3/s. The true max speed is actually a bit higher but I step it back a fair amount to make sure I get good repeatability.
First set your extruder temp (mine is 205C)
Gcode to test various extrusion speeds:
G91; Run the following multiple times until the extruder; starts skipping. Increase the F# by 100 each timeG1 E250 F300 ; extrude 250mm at 300mm/min
My max was F600, but I back it down to F500.
To calculate volumetric flow we take feedrate (500) x filament cross sectional area pi * (1.75mm/2)^2 = 2.405 => 20mm^3/s.
