The quark should be smooth, but your warrior shouldn't stutter when you go from 0 to WOT.

perhaps faulty cells?

Does it with all my packs, I don't think its the cells, they're matched 3700's, only had them since May, and have looked after them correctly with a balancing tray etc. Does it with my 3300's as well.

No leaking caps or a failing bec/receiver pack?

Using a 6v UBEC, which works fine - no stuttering on servo's. It only stutters going to WOT immediately, if I ease it in over the space of a second or so its fine. Its also fine pulling away to a medium speed, although it does cog for that split sec.

Caps aren't leaking, although there are only two on my model. 650uF 50v ones I think, not 100% though. One is easier to move around than the other, perhaps its become disconnected.

Btw do you know if the 9920 has thermal cut off? I've never encountered it so I presume it doesn't?

It still could be the ubec. did you tried reprogramming it, or do you have your epa set higher than it was with programming?

yes, it has got a thermal cut-off.

EPA's set to 100%, never saw the point in going over that with an electric. I tried reprogramming it a few days ago and haven't changed the EPA since then.

I don't have a reciever pack to hand to test with, nor any other ubec :( I'm going to order a new one with my Quark anyway so I'll swap them over and test then.

Suprised to hear it has a thermal cut-off, any idea what sorta temp it cuts off at? I've felt it get pretty hot before but its never cut-off. Mind you I'm not 100% sure what 180F feels like.

you need to realize that 50-53 degree C is too hot to hold. it feels like burning.

i would try a seperate receiverpack. or if you got the ability, hook up 2P of your 3700 cells.

True enough..think I'm going to go order a temp gun today. To my thumb theres 3 temps - cold, hot and burning.

What do you mean by 2P of the cells? You mean hook both up in parallel as a test?

Yeah, i doubt if they deliver the punch needed for the launch.

Running them in parallel makes them more than twice as powerfull.

I could run the car two batts in parallel with 5 mins of soldering.

To be honest its never been too big a problem so I've never given it much thought. But I'll run them in parallel this evening if the rain stops for 5 mins. Its probably just my batteries being a bit weak like you say.

That or another receiver pack. Please report back if you know more.

My girls truck stutter on 14 cells running the 9xl. but i think it too is trying to draw too much juice. i need like an 7 or 8 xl...it too runs on the 9920. Anywho, i think IMO, the quarks run way hotter than my 9920 with a fan. i have run the 9920 with 16cells and my 10xl geared 18/51 and no probs. But i can't run the same gearing with my Quark...i have to go down to 16/51...

my 7XL doesn't stutter at all, on 12, 14, 16 or 18 cells. it's just takes off without a fuzz.

you do use a fan on your 9920 but not on your quark?

I know Daniels quarks stays very, very cool on 5S lipo (set to 70 or 75 percent) it stays quite cold, even with his 'direct drive' centerdiff.

Hmm, if the Quarks going to run hotter, I may not bother. With the quark because it has a solid case, I could thermal epoxy it to the roll handle on my Savage to use that as a heatsink? I'm not running any fans in my truck at the mo, and would like to keep it that way if possible, so if I put a fan on and it fails, the system isn't going to thermal..

a heatsink needs to have a large surface, adding a flat piece of aluminum helps a bit, but it's not the purpose of a actual heatsink.

a fan helps removing the heat.. as long as the air is moving.