X30 vs Rotax

Our club that we race at allows Jrs to run x30 with 2021 updates and Rotax jr evo in the same group. If you run the X30 you can be 315 weight and the Rotax is 325 weight.

Everyone is saying the x30 with the new pipe is way slower so everyone is running rotax. We are think of running the x30 but wanted to hear some opinions on here before we did it. No one has run them against each other yet.

Thank you!!

There’s no clear answer I’m afraid. I do know the x30 seniors with new exhaust etc are quicker across the same track but there’s the thing.

Which will turn faster lap times is quite dependent on the track - x30 is happier on a twisty track due to the more linear power delivery whereas Rotax tends to suit a more flowing track that keeps it in the power band.

If you pit x30 vs Rotax at the x30 track here (Rak track), x30 obliterates the Rotax.

Put the same two karts and drivers against each other at Al Ain (designed for Rotax), Rotax wins every single time.

I remember when Nick was racing junior how amusing the rotax vs x30 battles at NJMP could be. Nick would have the top end speed and pull on the fast bits but Ryan would be pulling away corner exit midrange. They would accordion back and forth.

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So there is no really clear answer.

Yeah. I suppose if your series has only a couple tracks, you’d pick the engine package that would be “best” for where you race the most. From what you’ve said, sounds like rotax mid/bottom works best in your club.

Rotax is pretty compelling from a maintenance standpoint relative to x30 these days, however, so there’s that to consider as well.

What in the name of Sam Hill…

I’ll race you round the rectangle perimeter.

A Rotax junior has 4hp more than a current spec X30 Jr. Yes, 4hp. An X30 with the old 29 header and flex pipe is roughly equal, but versus current spec X30 (one piece pipe, 22.7 header), it’s not even close. The ten pound differential isn’t enough. Run the Rotax.

Forget any conversation regarding anything F-Series; they ran/run the 31 header for X30 Jr, which is basically a Senior (and gives it a big advantage over the Rotax). If we are talking about current Planet Earth rules, a current spec Rotax Jr has a 4 hp advantage over a current spec X30.


I was hoping you would chime in. WE have a Fox Rotax right now. Thank you.

Now to throw a wrench in…You can also run a ROK GP JR at 330 pounds. Do you think that will be any competition for the Rotax Jr?