Normally you can see if they are putting all the power to the front wheels fairly easily. How are the front tires doing. If it is chewing up the front tires definitely up the diff fluid weight. I just bought my first 1/8th buggy and I can't wait to get it converted. Driving it as nitro was good fun when it worked.
Yeah, the front tyres balloon when i give it some throttle.
>Would changing the centre diff fluid help much? See most people that run Brushless 8ights run 7000 or 10000 in the centre diff.
Increasing the diff fluid wheight will decrease unloading to the front tires which act like a big slipper. Thus traction normally will increase which results in an increase in amps too (as more power can be transfered to the ground). Higher Amp peaks will result in a hotter motor.
Very loose centerdiff = less amps, cooler motor
Those were my findings using an eagletree datalogger and comparing a center diff filled with grease, 10000 and 30000 silicone oil.