"Race" implies an organized event with specs for what they allow. Without those specs, or some idea how you'll be using it, its impossable to give a recomendation other than "Go Big 'n Go Fast"
As of right now I just want to get a fast kart that I can play around with on the track. There are no electric race kart race series (at least right now)
All the technology exists for a fast race kart...BUT..
the current state of battery technology will mean you either have a very limited "Track Time" ..5 to 10 min at most, ..OR you end up with a very heavy battery pack (50+ kg of LiPo) to allow a 20 min run time together with an expensive fast recharge system or spare ( $4k+) packs to swap between runs.
Old Zero X/MX drivetrains are awesome. The zero guys have built a lot of em and they're a riot for stealthy parking lot races. Perm or agni motor, with an alltrax AXE at 400amps and a zero battery = fun. Giant smoky burnouts, doughnuts and figure 8's are the norm. I'll dig up some pics and vids.
After a dozen races, some with 5-6 karts running simultaneously, this is the only crappy footage I could find... I don't think they really convey the sense of speed and acceleration these karts posses. 10-15 minutes of hard racing leaves you sore and sweaty Maybe we'll stage a race with a dedicated photographer soon.
[youtube]fVJbK4PBoGY[/youtube]
[youtube]CqZbK8x8tuw[/youtube]
[youtube]AslWdswOhCc[/youtube]
Yes, that's our beloved Luke, burning the tires off the wheels...
Sweet im working on this as well... When I get colossus running... But for now I just got a westinghouse 4.5hp 36v motor im sure i can push it a bit further. I will be building one for off road and then I want to get a shifter!!!
http://www.electrathon.com/regs/ Can't say that I care for some of their rules. Limit of 15 lbs. on Lipo batteries in your ride for instance. They do hold a bunch of races in the Spring though.