Flex3Drive Motor Stall

Hi all,
I recently built a delta printer (following dc42's guide with some modification). I added a Flex3Drive G5 remote extruder (40:1 gear ratio). Their recommended settings are as follows:
M350 E8 I0; microstepping M566 X1500 Y1500 Z1500 E6 ; jerk M201 X2000 Y2000 Z2000 E120; accel M203 X18000 Y18000 Z18000 E2400; max speed M906 X1500 Y1500 Z1500 E400 I60; current
I'm also using an E3D volcano for my hotend. E3D claims the max volumetric speed is 25 mm3/s.
I've found that my extruder stepper motor stalls at anything over 800mm/min. My steps/mm is set at 2450 mm/min with 8x microstepping (306.25 real steps) so I am being severely limited by my extruder motor. I ordered a new NEMA 17 pancake motor from StepperOnline (17HS081004S) to see if that makes a difference. My existing motor is a Usongshine US17HS4401S. Is there any other steps I could take to alleviate this limitation?
Thanks!

put the values into the emf calculator and see if you are limited by the max speed of your motor.

It's likely because your stepper motor is being commanded at too fast of a speed. To improve this, you'll want to find a stepper motor with the lowest inductance possible. I've found nema 17 with inductance of about 2 mH is the best you'll get. If lower, even better.
You probably still won't get as fast as you'd like, though. 40:1 is a lot of gear ratio.

Wait. Also, I just ran the math and 800 mm/min on the E axis (with 1.75 mm filament) is equal to 32.07 mm^3/sec. Is my math wrong? It seems to be exceeding the stated performance.

@bot I think I'm calculating this correctly. Here's my math:
800mm/min / 60s = 13.333 mm/s (1.75mm / 2)^2 * pi = .875 mm2 13.333 * .875 = 11.667 mm3/s
This definitely could be (and probably is) flawed.

@guerty25 I think your math is wrong.
800 mm/min = 13.333 linear mm per second
The volume of a cylinder of filament 0.875 radius and 13.333 height is given as: V=πr^2h=π·0.882·13.33≈32.06962
(Badly copy and pasted from google. Google for "volume of a cylinder" to get the calculator.)

@bot Wouldn't volume multiplied by speed give me mm^4/s? Shouldn't it be area times speed?

@guerty25 the benchmark is given in mm^3 per second. Time is an essential component of this.

@bot yep my math is flawed. If anyone else stumbles on this and is also bad at geometry here is a calculator.
In the end then I guess it doesn't really matter that my motor stalls at the higher speeds. 800mm/min is pushing the volumetric limits of the volcano, so I'll get underextrusion anyway. I did set the max volumetric speed in PrusaSlicer to 23 mm^3/s and it still stalled but that might have been acceleration or some other factor that I'll have to dig in to.

you could get a mosquito magnum. it can reach 3035 mm^3/sec.