Home Forums TaG Rotax Max Better starts from dead stop

This topic contains 5 replies, has 5 voices, and was last updated by  Ray Chiappe 5 years, 7 months ago.

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  • #20415

    Joe Ricard

    I got this crazy idea to try autocrossing my Rotax Sr.   Went pretty well after i got up on the pipe.  But getting there was agonizingly slow.   30 ft from start cones to timing lights  and would not be on the pipe for another 15 to 20 feet.

    How to get the Rotax up to speed quicker?  played with power valve with not much difference because no pipe pressure early.

    Is it a jetting thing?  I am set up as always for sprint race and weather station jetting recommendations.  


    Once on the pipe i was flying and able to keep it on the pipe even in the slower pinching in corners.    put 1.4 seconds on everything else out there including a formula mod car.

  • #20448

    Ted Hamilton

    On a single-speed vehicle, it’s all about compromise — how long can you hold the brake and throttle at the same time without burning your clutch up? Not familiar with the solo rules — if you can add an axle clutch too, that will allow you to set higher stall speed and get better starts. If it must remain RMax legal, it’s all about timing and dancing on the pedals…

    2014 Praga Dragon / IAME KA-100

  • #20499

    Rob Kozakowski

    The Rotax is just slow from a dead stop.  You can make very marginal improvements, but it’ll still be slow.

  • #20548

    Joe Ricard

    Well I got to do my post race maintenance and looked at the pipe and plug.  Fouled the plug and pipe was black.   weather was changing quickly and I dig not keep up with it.   Grid is far away from Paddock.  You can’t leave grid and I didn’t have a Ninja to get me a leaner jet.    So being pig rich was part of the slow launch.   Weather needed a 165 when I gridded up,  when I got back to the truck my station said 160 boarder 158

    Autocross is a just for fun thing for me these days.  Used to be so hooked on it with my shifter motor.

    • #20603

      Nick Esguerra

      Happened to catch this, obviously if you only intend to use it for autocross it may work.  Very experimental, but cool nonetheless.


  • #23483

    Ray Chiappe

    I have seen axle clutches used at Road Races. Don’t know if one will work with sprint gearing? I think a Rotax with a slippy clutch with say a stall around 7,000 rpm would be a rocket!

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