Joke. 45 MPH? There is a eKart class but it's lame indoor over-bumpered lame karts.
Someone is making a proper race kart for sprint racing that tops out at 84 MPH. Most sprint size tracks don't have a long straight, so 65-70 is about right except for shifter karts and larger motors. You gear for max RPM at the braking point, or just before.
AFAIK, eKarts have not made the local scene yet.
It's been many years since I sat in the seat of a kart,
running. I still have my 100cc Margay sprint Expert II (1982) that I won the state championship with in '84. Later in 84 I went enduro racing and batteries won't last for that. Races are now 45 mins whereas in my day they were an hour. Years before that they were 2 hours, but that proved to be too much especially with all the different classes.
In the Honda article it said the kart itself is 300 lbs without driver and it will run over 30 minutes on a battery. Sprint races are 10 laps in general.
A 100cc laydown kart at Big Willow on the backstraight with not too windy conditions was 103 MPH for me. Holding the throttle wide open it would scrub down to 90 for T8 which is just right. Only 16 HP, turns pull the speed down. It would do about 95 on the front straight and again wide open until T3 where a little brake was needed. Going up over the hill the climb pulled the kart down to about 50.
An electric kart might go good in that section with the torque they have. 100cc Stock Heavy (Yamaha or other) is an overall driver/kart weight of 360 to 370# depending on some minor rules. St at that weight and only 16 HP it's not an overwhelming acceleration. That I can see being a lot more fun with a fast eKart even with the weight disadvantage.
Some of the more exciting karts are shifters. You stay very busy in one of those. An eKart would be great in that you just go, no gears needed.