What Rps Drop Is Normal on a Spring Upgrade?

[NathanW8]

Hi,
I’m new to upgrades to airsoft. I have Tokyo Marui Sig 552 it was running at 85m/s and 14rps with a 7.2v20c lipo and 25rps with 11.1v lipo with a Warfet mosfet. I’ve just fitted the Guarder full tune up kit with a SP100 spring. The gearbox went back together happily and all seemed good at its at 100m/s, but now it won’t turn over with the 7.2v20c and I’m getting 16rps with a 11.1v20c. The Sig has a EG1000 motor which I thought would have lots of torque, so wasn’t expecting such a large drop in the rate of fire. Is this normal or has something gone wrong? If this is normal, what would I need to change to get the rate of fire back to ~25 rps?
 

 

[Skara]

25 on a 11.1 with presumably stock gears is a lot. I mean, my M4s run 13:1s and SHS HT motors (which aren't exactly high torque, they're in between a proper HT and a HS motor) pull 27/30 RPS on 11.1s, so I suspect that the EG1000 isn't torquey at all but just fast.

Also it has ferrite magnets which are noticeably "weaker" than rare earth ones. Keep in mind that SP springs are rated in ms/0.25s so the SP100 is equivalent to a M110 which might be too much for the motor to handle.

I guess the grip gets pretty warm even after a short burst, so the motor is doing a job it's not supposed to.

OR you might have messed up the shimming somehow.

 

[NathanW8]

@SkaraThanks for the help. I've just done a full strip down and rebuild. Looks like when I fitted the motor end plate I pinched wire pressing the motor in too far and over loaded the bevel gear. This caused alot of friction on the right side bush and it picked up on the shim. After a clean out, new shim and regrease its sounds much better and will turn over happily on a 7.2v. Later I'll chronograph it to ensure it's ok.