Stock SV27 Surges Except At Full Throttle

[ksm2001]

I’m having an issue with my SV27 where it surges at part throttle, found it to be fine at full throttle and was wondering if anyone else has experienced this problem?

Setup= Stock motor, stock esc with red wire removed, Spektrum DX3.0 radio, 4s PolyRC 4900xp, Novak Smart-Stop 4-Cell Lipo Cut-Off, Turnigy ubec, x642 prop.

This was one of first SV’s when they came out, it ran fine last 2 seasons using a separate Rx 4cell NiMH pack, but this spring removed it and replaced it with a turnigy ubec, this is when I noticed the problem, not sure if its coincidence or had somthing to do with the ubec, or the esc is just giving out.

Tried 2 different sets of lipo's, same surge at part throttle.

Switched the motor for another SV27 motor, same problem.

Removed the ubec and Novak smart-stop lipo cut off, put a 4 cell NiMH Rx pack back in , same problem

Switched the receiver with another from my DF29 which is known good, same surge at part throttle.

I think I’ve eliminated all the parts except the esc now which only leaves me to believe its the esc,I have a spare castle 120 I’ll try but was also wondering how it works with the stock sv motor and what I should set the timming to using version 1.04?

Ken

[Flying Scotsman]

Ken, the 120 should work fine. The SV27 motor is I believe 4 pole and should be normal timing or arround 9 degrees on V1.4. Check your motor temps and reduce timing if hot

Douggie

[line6]

The Sv motor is a 6pole motor. I had bad luck with a h120 and the Sv but that was with the old firm ware.

[ksm2001]

I'll try version 1.4 with normal timing 9 degrees, thanks Douggie.

Line6, I know that on version 1.03 normal timing was set to 16.25 and think that this was the most likely cause for on the sv motors. I'll try it this weekend and post results.

Thanks
Ken

[ksm2001]

Tried the SV27 this past weekend with the CC 120 version 1.04 normal timing (9 degrees) and it works great. Stock esc was the problem.

When I removed the stock esc I noticed the capacitor bulged on the end. Good thing it only surged at part throttle and not

Ken

[arisarts]

Tried the SV27 this past weekend with the CC 120 version 1.04 normal timing (9 degrees) and it works great. Stock esc was the problem.

When I removed the stock esc I noticed the capacitor bulged on the end. Good thing it only surged at part throttle and not

Ken

Add some capacitors to the stock esc and test it.

Remove the old one if you can and put the new ones in parallel to the battery input.

You can find the ZLH capacitors at kintecracing.com under UL-1 upgrades for 1$ each.

Regards

Aris