Most people ask me how fast he goes, not about the kart’s HP.

Running the KT100 with Jr Sportsman restricted intake (races against C-80) I’ve seen my son hit 60MPH on a long straight. We probably could have geared for more speed but had to balance gearing for corner exit power with straightaway speed.

Horsepower is relative, same dyno, same day different readings.
I’m guessing that 8HP is a tad high, but close to a max in this class (C-80)
Racestudio’s “engine analysis” says we’re making close to 6HP calculating from change in speed (Power = Work/Time)

Rotax, next year :)

I just tell them imagine going highway speeds in the walmart parking lot.

Gif

I’ve been told a 125 shifter kart will do 0-60 in 3.5 seconds and tops out at about 120 MPH.

Some 125cc shifter data from my last autocross that had a “drag” start.  I suspect others can and have done much better…. I’m new to shifters, and haven’t really done much tuning yet.

– 0-50mph (speed before we lifted for first corner) @ launch: 2.7s

– 60ft times: 1.7s @ 43mph

Based on that 0-60 in 3.5s seems very doable.  No idea what top speed is, since I’ve always run out of straightaway long before I was starting to feel any aero drag.