Choosing the right brushless motor
My first post, and somewhat longer than intended.
I'm looking for some advice on what recommendations / expectations I should have for a brushless system in a Kyosho Mini Inferno buggy. I'd like to increase real use top speed, but not make it insane or risk damaging the stock transmission or spend more than its worth (it's for my kids in the back garden - and me!) . I'd prefer to avoid Lipo for now.
Current setup is a hobbywing ESC, stock motor, and a modified battery layout to take 8x full size AA batteries with the space gained from smaller electronics☺
I measured the current car /motor speeds at
No Load (suspended) = 47km/h (29mph) = 41,000rpm
Carpet = 21km/h (13mph) = 18,000rpm
Paving = 20km/h (12mph) = 17,000rpm
Cut Grass = 13km/h (8mph) = 12,000rpm
(gearing is 10.8:1, speed measured using a 50fps camera at the end of an 8 metre run-up).
My question is - what spec of brushless motor would give a reasonable speed increase without needing other upgrades beyond an ESC? Is the limiting factor actually acceleration / torque in this case rather than raw rpm? Would something fairly low like a 3000kv motor be better than a higher kv rating? (reducing theoretical top speed, but increasing actual speed due to the torque). Would I get longer run times? Would the NiMH batteries quickly limit any performance gain?
Or am I not going to see a worthwhile improvement and so shouldn't bother? Should I just get a better bruhed motor instead?
Many thanks