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Hi,

I have some small amounts of RFI on my aircraft. I fly with NGK DP9EA-9. I tried the resistor type plugs DPR9EA-9 witch was 100% better. BUT, when passing 30-32" of MP the engine dies out. Seems to me like the spark is not powerfull enough when running into boost. I tried gapping all the way down to .5-.4mm. Dident help.

Anyone else had similar problems ? Sugestions to other plugs ? Anyone flying iridium/platinum plugs ?

Thanks
  • Re: 914 spark plugs

    by » 12 years ago


    Hi. Thomas,

    The gap should be between .6 - .7 with ND X27EPR-U9 or the NGK equivalent. Imprope gap especially too small could affect your performance as you have described. NGK's tend to be good plugs for your 914. If you are using the proper plug and gap then I doubt it's the plugs that are the problem.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell


  • Re: 914 spark plugs

    by » 12 years ago


    Hi Thomas,
    What do you mean by dying out? If the mag check is good at 4000 rpm the ignition should be OK. Could it be a fuel problem?
    Rob

  • Re: 914 spark plugs

    by » 12 years ago


    With DP9EA-9 .5 gap the engine runs fine all the way up to 5800rpm and 50".
    Once I put R plugs in same gap the engine dies out once I run past normalized MP.
    the mag check is just fine, no significant drop.
    So there's no chance that using both resistor caps and plugs can add to much resistance and weaken the spark ?
    Once I put the non-resistor plugs back in, it runs just fine.

    So how come shops like CPS sells the non-resistor plugs DP9EA-9 for 914 ?

    Thanks

  • Re: 914 spark plugs

    by » 12 years ago


    50 inches??? your going to damage your engine. Have you calibrated your throttle? why is is going to 50 inches?

  • Re: 914 spark plugs

    by » 12 years ago


    I have built a custom EFI, turbo intercooler 912UL. Cruise 25-35". 45-50" only for TO ;)

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