We are starting a new American S16D GTP class at Speedzone. Ive built missile 16d motors. A few have even won Nats races. I love building motors and speak fluent D Can. That being said i have precious little experience with
Super 16d arms and their nuances.

My experience building 16D motors is extensive. You really have to pay attention when extracting hp from those fickle arms. They have long stacks and 70 turns of 30 gauge. S16D arms have less then half the resistance (46%) of 16d.

I built 7, small diameter s16d motors to test and learned that they work surprisingly well with big air gaps. A few motors were natural coated and not stack ground @ .530, 2 were. 518 all in .575 to .585 holes.. Half had kelly angled magnets, other half proslot FX. 2 motors ran like **** with no brakes. Brush faces burned a bit. Do s16d motors require stronger springs then Champion reds? I geared them 10:37 and .720 tire. Hotlapping showed no slowing after 40 laps.

Anyway I'm building a .560 (.563) arm next in a fx setup with strong fx mags next.