5 cell + mamba 25 in a tenth scale for racing?

mamba 25 done. Did a 5s test with lower gearing, and freshly charged batts. Cogging not much of an issue with lower gearing, couple other quick checks ok, and staight to the hill for part throttle testing. I had already performed same test repeatedly with half charged 5s and much taller gearing. This time I expected temps to drop (lower gearing), I didn't even start up the hill and puff. It seems the fresh pack put voltage a little to high.

After this I got to talk to a very knowledgeable brushless airplane guy. Here are a few thoughts he had-
#1 - at full throttle fets don't work nearly as hard as at part throttle (what I saw in testing proved this even @ lower voltages, but went critical on higher)
#2 - out-runners are not the best motors to try to over power; they suffer iron saturation and act almost like a dead short when overloaded
#3 - cheap batts cause ripple currents ( a little spike getting through the cap would easily kill the fets., but the higher nominal voltage good batts would provide would not be good either on 5s)

So. if I want to continue I need to go with a top notch motor (Neu or mega), best quality 4s pack, and gear to use full throttle as much as possible

[jhautz]

I can already hear the ''I told you so from Serum'' :005:

But just cuz this setup failed I don't think the idea is a total failure. I actually think that you could make a small setup like this work with, as you said, '' a top quality motor'', but also try the Quark 33. It is actually rated for 5s and has a heat sink built in.

Back at it again, this time armed with an eagle tree. Probabely going to set myself up for another told-ya-so; atleast this time we will have graphs when it goes. I can't decide on witch motor or batts. Sower's 1105 3S LOSI is a proven way to go, but I cant easily gear low enough for a 6800kv on 3s. Half way through this thread, 1/10th 4wd buggy ?? , he gives a little more info on the buggy jhautz posted for me. RURC on hobbytalk runs a b4 (really light) with mamba 25 on 2s and claims good results. I'm still leaning towards 4s for t.c.: need to do more testing.
New test combo (all old stuff laying around) novak 4300 - 3s 2100 20c - castle phoenix 25 - tc3. Testing in the driveway (brushed concrete) with foam tires, the max amp draw was 20.89 @ 209 watts according to the eagle tree. Gearing was 98/22 WITH 2.05 IN. FOAMS. TOP SPEED 23 MPH (calculated @10 volts). Tires were spinnig on concrete, will try to test on carpet track thur. So far, max temp. of esc was 140F (no shrink wrap, no fan, and no heat sink), doing a 10 second donout. On carpet in the hallway I got enough traction to spike 22 amps 232 watts.