How fast are the VXLs really are?

[Mozzy]

I don't believe that the brand of cells makes that much of a difference, as I have tried both a cheap chinese 3800mAh 20C 4S & a Maxamps 6000mAh 20C 4S, back to back, & the only difference was very slightly lower on initial punch with the 3800 (due to available amps.) & run time was longer with the 6000 (obviously). Top speed was the same in a converted Revo with stock gearing & a X1-CRT with stock gearing.

So, I don't see what could've been wrong with you batts to make that much of a difference.

Either way, they're still faster than nitro!!!