1. Nathan Sitko - 625 TAD/TAFC

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    Hey everyone,

    We're running an autometer data logger on our FC with a mallory/cirello supermag and I'm wondering if installing some sort of noise filter would make my engine RPM data a bit smoother. Everything else reads quite nice, but the engine RPM is picked up off the coil through the 9118 magneto signal converter box (the shift light also comes off the same box and is a bit jumpy too).

    What brand/part number is anybody using with success?

    Thanks,

    Nathan
     
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  2. john348

    john348 Top Alcohol

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    Nathan

    Years ago when we ran a SM that Tom had hopped up we ended up using a single magnet and sensor at the flywheel to help "calm" down the EMF from the mag to get our RPM
    We drill the flywheel glued the magnet in it and drilled and tapped the motorplate for the prox
    Seemed at the time the only way to get a accurate reading
    but we stll had to change out proxes every so often as the flywheel flexing would eat them.
     
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  3. Nathan Sitko - 625 TAD/TAFC

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    We used to run the rpm off magnets in the degree ring, but it has been hard to find replacement sensors for our computer when they get broken, so we went this route (mostly the wires get broken right at the base).
     
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  4. Cpt Kludge

    Cpt Kludge Member

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    One thing you might try is to lower the sample rate on your tach pickup channel if possible. This will have the effect of smoothing the data somewhat. Is the wire coming back from your tach pickup a shielded cable? I'm not very familiar with the RPM stuff.
    We always tried to use the magnetic RPM sensors with our systems as they were more reliable and accurate once installed properly. The best way to keep your mag RPM sensors from breaking the wires at the base of the sensor is to secure the wire coming out within an inch from the base of the sensor. We used to build sort of a U bracket, when possible, that we could both mount the pickup to and secure the cable and inch or so back from the sensor pickup. You have to keep the cable coming out of the sensor from flexing at the base of the sensor other wise the copper wire(s) will ultimately break and fail.

    Steve Northrop
     
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