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308 spark plugs

Discussion in '308/328' started by jon s, Jun 23, 2008.

  1. jon s

    jon s Formula Junior

    Mar 9, 2005
    509
    pocasset ma
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    jon shoukimas MD
    i'm curious about the debate about platinum (or iridium) needle electrode spark plug versus the old style. at the recommendation of the mechanic who redid the heads last year i'm using ngk bp 6 es's because he thinks you get a better flame front with the old style, fat electrodes. has any one ever dyno'd any engine with old versus new style electodes to see if it makes a difference? regards, jon s.
     
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  3. Ferraripilot

    Ferraripilot F1 World Champ
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    May 10, 2006
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    Do not waste your time with platinum plugs. Those who had tried ngk iridium plugs have had success with them although I cannot justify the expense and I doubt there is any performance gain. The iridium plugs may last a little longer, but I prefer replacing the plugs often so I can see what is going on inside the engine on a regular basis. Better to know if something is going awry before it does. Use NGK BP6ES and replace them every couple months or so depending on how much you drive the car and you will be pleased.
     
  4. FasterIsBetter

    FasterIsBetter F1 Veteran

    Jul 22, 2004
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    +1 on NGK BP6ES. Unless you are running really, really rich, or you are racing your car, there is no need to change plugs every few months. Once every year or two is more than often enough for ordinary street use, or even "spirited" driving. It doesn't hurt to check a plug on each bank now and then to be sure they are not getting too dirty. But if the car is running well, chances are the plugs are fine and don't need to be changed very often.
     
  5. jon s

    jon s Formula Junior

    Mar 9, 2005
    509
    pocasset ma
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    jon shoukimas MD
    i agree that the bp6es work just fine for street use in my 81 2valve and i usually don't change plugs for at least 10k miles (worked fine for many alfa's). the real question though is is my mechanic right - are the fat electrodes superior in power output to the new needle types. and i think that question requires a dyno. regards, jon s.
     
  6. FasterIsBetter

    FasterIsBetter F1 Veteran

    Jul 22, 2004
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    IMHO, there will not be a noticeable difference in engine power between the regular plugs and the Iridium plugs. If there is any difference, it will be so small as not to be felt seat of the pants. I have never seen anything that proves there is a significant power difference. It is my understanding that the main difference is serviceable life. The iridium plugs are used in the newer cars to extend the service intervals and to handle the computerized ignition systems and direct discharge coils. In an older car, changing to iridium buys you nothing except more expensive plugs.
     
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  8. fastradio

    fastradio F1 Rookie
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    Apr 26, 2006
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    David Feinberg
    While there may be be no "noticeable difference in power", the performance of the Iridium plugs remains consistent over it's longer life span...hence, more consistent hp output over the life of the spark plug.

    All cars, regarless of age or ignition type rely on the spark plugs. The plugs doesn't know the diffference between fuel injection and Weber carbs. Longer plug life benefits all engine types.

    Really? The fine wire electrodes used in the Iridium plug resists fouling due to it's higher tip temperature and is truly self-cleaning. How do you explain that the Iridium plugs in my 365bb have been in for 5 years and yet, I was lucky to get one season out of the comparable BP7ES, with no other changes...Note that the BB has no choke or cold starting circuit, so it's "pump and pray" on a cold start. This certainly is a good test for any spark plug "foul resisting" capabilities.

    Most folks, with "older cars" who have switched to the Iridum plugs experiece better running cold and a smoother idle.

    Of course, your mileage may vary...

    Regards,
    David
     
  9. Ferraripilot

    Ferraripilot F1 World Champ
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    Your mechanic is talking about the dynamics of the flame kernel and flame quenching of the spark which a particular electrode generates. I have personally not had great luck with exotic spark plugs on old Ferrari's, which is not to say others have not had good luck with them. I agree with the above poster in that there will not be any difference in power, and if there is, it will not be anything you will be able to notice by the seat of your pants. If they make another 2bhp I would be surprised really. Do not give trivial things such as spark plugs too much thought, and go with what you want while knowing what the concensus is here :) We are not reinventing the wheel here.
     
  10. FasterIsBetter

    FasterIsBetter F1 Veteran

    Jul 22, 2004
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    David,

    I thought I'd made it clear that longer life, as you've experienced, is a benefit of the iridium plugs. I'm glad you have experienced better performance. I'm not surprised that you have found the iridiums better than the BP7ES plugs. In my experience with these cars, the BP7 is too cold a plug. I've found the BP6s seem to burn better and give more consistent running, and hold up well over time.

    But as you said, YMMV.

    Steve
     
  11. reuven

    reuven Karting

    Apr 22, 2007
    120
    Israel
    I am using BP8ES they are a lot better in the range between 6000-8000 RPM.
    If you are running the engine on low rpm then BP6 or BP7 are better but on high rpm it is better to use colder ones.

    Reuven
     
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  13. miketuason

    miketuason F1 World Champ
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    How does the Iridiums perform on a QV? I plan to get a set.
     
  14. fastradio

    fastradio F1 Rookie
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    Actually Steve, with the JE 12:1 compression pistons I'm running, the "7" heat range really works out quite well. For a more normal Ferrari engine, I agree with you that the BP6ES is a much better choice.

    Regards,
    David
     
  15. reuven

    reuven Karting

    Apr 22, 2007
    120
    Israel
    On 12:1 I would use BP9 or B9.
    High comp engine works the best on high rpm and needs colder plugs.
    Reuven
     
  16. f355spider

    f355spider F1 World Champ
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    May 29, 2001
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    It can vary depending on the version of 308 we are talking about. Definitely the carb 308's prefer the NGK 6, but the FI 308's can often run fine on a NGK 6 or colder 7.
     
  17. 308-newbie

    308-newbie Guest

    went to MSD ignition and iridiums...it is like a new car. Never driven a carb car like this. It's all about the spark and the mechanic that balances it all out. Even the neighbor "heard" the difference.
     

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