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Spark Plugs?

Discussion in 'Forced Induction' started by spydy43, Oct 28, 2004.

  1. spydy43

    spydy43 Senior Member

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    I wanted to know what kind of spark plugs people are using with their turbo setups. I have heard that you need to lower the gap from OEM specs, is this true?
    I usually stick with NGK plugs that are one step colder than stock but I am having to change them out every 2k or so becuase they are fouled. Any recomendations?
    I am runnin a t3 on a d16y8 at a max of 10lbs of boost.
     
  2. pissedoffsol

    pissedoffsol RETIRED

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    going to a smaller gap is to prevent the spark from being blow out by the turbo "wind" so to speak.

    if you're fouling out plugs, you're not tuned right. you're probably running an fmu, aren't you? lol
     
  3. projekteg

    projekteg Senior Member

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    run one or two step colder ngk's with .28 gap, and yeah, if you're fouling them out like that, you're running too rich.
     
  4. spydy43

    spydy43 Senior Member

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    Yeah I am running an FMU better rich than lean I figure, this will be the case till I can get uberdata setup.
     
  5. pissedoffsol

    pissedoffsol RETIRED

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    an fmu is probably not running rich up top on 10 psi off a super 60. you're probably rich in the mid band, and runing lean up top.

    i'd turn down the boost if i were you.

    10 psi + fmu = asking for trouble.

    and don't go to a .028 gap plug. thats REAL cold. thats 400hp range.

    stock is .052, i'd go to a mid 30 at the least.
     
  6. projekteg

    projekteg Senior Member

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    gap really depends, but not so much on hp rating, go with the biggest possible gap without blowing it out, in my case, it was .28 at only 13 psi, i know a lot of people that pre gap to .28 just to avoid any possible spark blow out.
     
  7. pissedoffsol

    pissedoffsol RETIRED

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    IMO, thats a horrible idea.
     
  8. projekteg

    projekteg Senior Member

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  9. pissedoffsol

    pissedoffsol RETIRED

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    because lower gap robs power by burning cooler

    its like running 4:1 compression instead of 9:1 cuz its "safer".
     
  10. livinlow

    livinlow Member

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    Is there a good place to figure out the best plug and gap for a particular setup? From the sounds of it I would want a low .3 for around 300 hp on 10 psi?
     
  11. pissedoffsol

    pissedoffsol RETIRED

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    yeah, i'll post a link tomorrow- i ahve it bookmarked on my work pc
     
  12. projekteg

    projekteg Senior Member

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    so regardless of if you're blowing out spark with a .3x gap, it's still the best gap to run unless you're making 400+ whp?
     
  13. pissedoffsol

    pissedoffsol RETIRED

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  14. projekteg

    projekteg Senior Member

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    bkr73-11's with a .28 gap works best for my turbo b16 and i'm not in the "400 hp range", so it just goes to show, every set up is different and basically you should run the biggest possible gap without blowing out the spark, i had mine at .32 before i gapped them at .28 and it was still blowing out.
     
  15. spydy43

    spydy43 Senior Member

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    The car was street tuned on a wideband and the numbers were good up to 12 psi where the ratio dropped a little and we did not want to turn it a. The guy doing the work turned it down to 10 and said he was very comfortable with the air/fuel ratio he was getting. Should I still turn the boost down and if so what should I lower it to?
     
  16. projekteg

    projekteg Senior Member

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    how do you tune an fmu :( anyways, youre afr may have looked decent, but the fact that all the fmu does is raises fuel pressure as it see's boost, so the more boost you run, the higher you're fuel pressure is which means your injectors are prolly way over 100% duty cycle and if you have a stock fuel pump, it will probably shit on you real soon too. i would suggest no more than 7 psi on an fmu. if you want to run higher boost, invest in some better managment. you don't want to have to rebuild/replace you engine b/c you skimped out a few hundred bucks. fuel management/tuning is the most important thing to making a turbo'd car run safely and last.
     
  17. [Freemantle]

    [Freemantle] Senior Member

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    FMU dosen't touch duty cycle, just fuel pressure. Adding fuel pressure gives you diminishing returns as it increases. Fuel injection is a function of load and rpm, not load alone. That's why the FMU will never be right more than once a gear. I don't reccomend running anything but vacuum with an FMU. Buy the Hack if Uberdata/Hondata scares you.
     
  18. pissedoffsol

    pissedoffsol RETIRED

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    thats what i was about to say. how the hell do you tune a non-tunable object such as an fmu?
     
  19. spydy43

    spydy43 Senior Member

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    I guess it wasnt so much a tune but they ran it through full boost to make sure the air:fuel ratio looked good.
     
  20. [Freemantle]

    [Freemantle] Senior Member

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    Trust me, because I've seen FMU turbo Honda's all over south Florida, their A/F didn't look good. Maybe it looked like the FMU was working, but it didn't look good.
     
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