Home Forums Tech Talk Download Actual Acceleration Data

This topic contains 5 replies, has 5 voices, and was last updated by  jt colegrove 2 months, 2 weeks ago.

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  • #79055

    Jason Wells
    Participant

    Can someone point me to a resource where a driver has posted actual lateral and longitudinal acceleration data; preferably on a shifter, preferably from someone who is on the limit? (i.e. not me)

    I don’t have this stuff on my kart, but I would like to do some calculations using good data. The rumor is that karts will pull like a million gs in all four space-time dimensions at .9c, but I’m skeptical. ūüôā

    My google-fu is only turning up ads for data acquisition systems.

    Regards,

    Jason

    #79060

    Brian Spek
    Participant

    we don’t have a lot of high speed turns at the AMP track, Stock Honda shows max 2.8G braking, and 2.3G Accel on one of our better laps. ¬†Lateral G’s are pretty similar at 2.78 and 2.69, but we get an occasional 4g lateral when we don’t¬†take a 2nd gear downhill/uphill corner correctly, or 3.8g lateral in a 3rd gear corner. ¬†these were in cooler weather during Nov-January, between 45-60 degrees, sunny.

    #79072

    Jason Wells
    Participant

    Thanks a bunch. That gives me a much better starting point for calculations than I had.

    #79081

    Alan Sheidler
    Participant

    The lateral G’s seem appropriate, and the braking level does not surprise me either.¬† But unless there is a 1st gear corner, 2.3 for acceleration seems high to me.¬† Maybe 2nd gear with a strong motor.¬† But 3rd gear or higher?

    It has been a while since I used a data acquisition setup on a shifter, but I don’t recall getting anywhere near that kind of acceleration after I was already on track.¬† Standing starts could produce high numbers with sprint gearing, but again, that is for the launch and 1st gear.

    The braking and cornering numbers are not affected by speed, but acceleration certainly is.¬† Aerodynamic drag reduces acceleration as velocity increases, especially on long tracks.¬† But the big killer at sprint or road racing speeds is the reduction of torque at the rear axle with each change to a higher gear.¬† As I say, the numbers are fuzzy since it has been over a decade, but in even 5th gear you won’t get 0.5 G, I don’t think.

    #79095

    tony zambos
    Participant

    Try YouTube. Some karters will include data overlays.

    Example:

    LAD Specialties / tony kart / rotax / kt100

    #80302

    jt colegrove
    Participant

    Depends on whether you’re using the GPS data, which is calculated based on your change in position, or the accelerometers.

     

    Accelerometers are noisy, and it’s easy to get distracted with shock/peak values.

    GPS data is nice and smooth, but won’t always tell you the full picture.

    Your peak values are going to depend on the corner, track surface, temperatures, tire wear, etc…

    Your best bet is to look at your data all the time and develop an understanding of the performance envelop of your kart with you driving.

    In my TAG I’ve seen GPS values as high as 5G in the banked turn at Boston F1 outdoors. ¬†4G+ accelerometer data isn’t out of the question either for peak values.

    In theory, a lighter kart like a JR should be able to produce more lateral acceleration than a TAG, which should produce more lateral G than a shifter.  This is due to the CF of a tire decreasing as normal load is increased.

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