Which Spark Plugs?! Denso SC20HR11, SC16HR11, or IXEH20TT??

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by HaiImBrian, Jul 11, 2018.

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  1. Denso SC20HR11 (Original in manual)

    85.7%
  2. Denso SC16HR11 (New hotter plugs that Toyota superseded original plugs)

    0 vote(s)
    0.0%
  3. Denso IXEH20TT (Brand new tech offered by Denso)

    14.3%
  1. HaiImBrian

    HaiImBrian Junior Member

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    This seems like a simple question but it really is not. I've done some research and since the plugs in our Prius pretty much last forever, I wanna put the best and correct one in. Each of these has been recommended and I was wondering which one to get.

    Denso SC20HR11 - Original Plug that is stated in the owners manual

    Denso SC16HR11 - New plugs that were superseded by Toyota to replace SC20HR11??
    Read More: Gen 3 Prius Spark Plugs superceded with hotter plugs | PriusChat

    Denso IXEH20TT - Brand new plugs and seems like the best tech available. but... these have different gaps than original. Gap at 0.040 instead of 0.044

    [​IMG]
     
  2. Luckykat32

    Luckykat32 New Member

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    I'm currently using the new 44's and they feel fine. I think it's because I have a bad egr, but my car just started throwing misfire codes....i know more by next week
     
  3. fopoku2k2

    fopoku2k2 Member

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    I'm interested in the recommendations from other users since it's been bothering me too

    Mi MIX 2S ?
     
  4. bisco

    bisco cookie crumbler

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    what are the oems?
     
  5. kbeck

    kbeck Active Member

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    I replaced the plugs week before last, holding my Official User Manual open to the page listing the spark plug part number. If it worked to 135,000 miles without a problem with the SC20H11, why risk fate with a different part? Now, had it been a later model Prius that called for the hotter plugs, or if the SC20H11 was Manufacture Discontinued (which it wasn't at Advanced Auto), then I'd have a different answer.
    But I have a lot less angst about this kind of thing after replacing the plugs. The ones I took out were good looking (tan on the ceramic) and, while a bit worn, the gap was still pretty close. Compare this to my olde '71 VW Beetle which needed new plugs every 12,000 miles, not to mention distributor points and condensor, and everything had to be checked and re-gapped at 6,000 miles. And a new distributor every 50,000 miles or so because the distributor shaft would get wobbly on its bearings.. The Prius is a dream by comparison, despite having to take out the windshield wipers to do the work :).
     
  6. milkman44

    milkman44 Active Member

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  7. HaiImBrian

    HaiImBrian Junior Member

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    They are the SC20HR11, but if you dig around the fourms, it is saying that these plugs are being replaced with a hotter SC16HR11

    You're right about this. My stock plugs have been great(SC20HR11) and lasted me this long but as Prius owners, we want to maximize the efficiency of the car. If this is the new recommendation from toyota.... shouldn't we move towards it? Spark plugs make a huge impact on engine efficiency.


    Yea these are the new TT dual iridium tip ones that are on the poll as well. Denso IXEH20TT

    Has anyone else installed these?
     
  8. bisco

    bisco cookie crumbler

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    i wonder if and when toyota made the switch, and if any members have seen the new plugs in their cars?
     
  9. sam spade 2

    sam spade 2 Active Member

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    No they don't. A spark is a spark. You have been brainwashed.

    Unless one kind of plug somehow somehow sends some of the voltage somewhere else besides into the spark, all of the claims about superiority are just marketing hype.

    And you need to understand what a "hotter plug" really is.
    That does NOT mean that the spark is hotter.
    It means that the design keeps the electrodes at a higher temperature; the spark is exactly the same.

    You only need a hotter plug if what you have now tends to foul with carbon.

    Having the electrodes run at a higher temperature might actually create a "hot spot" that contributes to compression pre-ignition and loss of power and potential engine damage.
     
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  10. milkman44

    milkman44 Active Member

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    I thought these were the correct plugs so I ordered a set and installed at about 145,000 miles, just after 180,000 miles I started having intermittent misfires. I put the original plugs back in and no more misfires. The original plugs now have another 9,000 miles on them and still doing fine. The plugs that are listed as the right ones are iridium, but have a platinum ground electrode and didn't hold up.

    https://www.rockauto.com/en/moreinfo.php?pk=1293084&cc=1444360&jsn=369
     
  11. m.wynn

    m.wynn Senior Member

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    Me thinks Toy is spec-ing the hotter plug in hopes they will burn coolant better:cool:...

    Based on how basically brand new my 2010's plugs looked at 120k miles, I'll stick with the 20's when it comes plug time for my 2014. The last thing these engines need (in my opinion) is a plug which may contribute to pre-igntion compounding the EGR issues. Sheesh...
     
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  12. CR94

    CR94 Senior Member

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    Maybe you need the hotter plug to avoid plug fouling after the oil consumption reaches Toyota's "normal" rate of 1liter/1000km? Or earlier, if doing mostly short, low-speed trips? They must've found a problem with the 20s in some undisclosed circumstance.
     
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