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Anyone try indexing spark plugs?

Discussion in 'Gen 2 Prius Accessories & Modifications' started by snijd, Mar 26, 2009.

  1. snijd

    snijd DIY or die

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    Happened across a couple of mentions of success with indexing spark plugs, and wondered whether anyone might have tried it on a Prius. Thinking it might yield an extra horsepower or so, and thought I would give it a go, unless someone's tested it with definite neutral or negative effects.

    See Indexing Spark Plugs | Advance Auto Parts
     
    #1 snijd, Mar 26, 2009
  2. Qlara

    Qlara New Member

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    I wonder if Prius ICE is using the 'open-end' type of spark-plug (like those in Bosch Platinum 2+ or 4+) where its ground electrodes are not 'blocking' the tip like in the conventional plug. Then indexing will not be a concern.
     
    #2 Qlara, Mar 26, 2009
  3. Mike Dimmick

    Mike Dimmick Active Member

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    Indexing is really not important most of the time. The original Honda Insight had indexed plugs; the cylinder head was marked with the correct plug (one of four, A B C D) to use and the plugs were also marked.

    The Prius OE plug is Denso SK16R11. A guide to Denso code numbers is here.

    SK = 14mm thread x 16mm spanner, mini-iridium plug (0.7mm centre electrode)
    16 = heat range
    No special reach spec
    No special shape spec
    R = With integrated resistor
    No special electrode shape
    11 = Electrode gap 1.1mm (.044")
     
    #3 Mike Dimmick, Mar 26, 2009
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