Yeah, aren't Scaley wall wart transformers rated at 16v output?
All the dirt modified replicas I built around 2007 for my new wood oval had electric toothbrush motors in them. I got the idea from the AC2car site and found a salvage store selling them for $1. A handful of cars still have long can toothbrush motors in them and despite being twitchy are as fast as cars with MT-5 and other slot car motors I now by online.
You just have to be real light on the trigger coming out of the turns.
Slothead