Hahn Turbo Spark Plug Questions

    For those of you who might have been following my oil pump priming process, a short update before my question(s). I used my DIY pressure luber to force oil thru the engine's oil lines and then cranked the engine using the starter while the coils and fuel injectors were disconnected and oil came thru the turbo oil feed line. I then waited 4 days and tried again and then tried again today. Each time, oil started flowing during the 4th starter crank cycle, so I'm happy there is oil flowing thru the motor.


    Now my questions - In an old spark plug thread over on TDS, Funinthesun posted an NGK engineer had recommended using an NGK 92182 Iridium plug, pre-gapped to .036. Since I prefer the longer life of iridium spark plugs, I ordered some NGK 92182 plugs thru Oreilly. Hahn recommends their standard NGK 4306 plugs. When I went to swap the plugs, I found that Iridium plugs (AC Delco 41-103/12625058) were already installed, presumably by my dealer during a service, or else Polaris actually shipped my Slingshot that way. Since Hahn says the original plugs can be regapped to .030 and reinstalled, I regapped the AC Delco plugs to the .036 used by the NGK 92182 plugs and reinstalled them since the AC Delco plugs looked pretty clean.


    Anybody tried using either the AC Delco Iridium plugs or the NGK 92182 Iridium plugs? The NGK 5306 V-Power copper plugs?


    Just thought I'd ask before going out to finish wiring the SCG-1 Bost/AFR gauge and then test-starting the engine.

    Edited 2 times, last by BKL ().

    Just FYI, Hahn recommends the 4306 NGK plug and tighten the gap down to .030 gap as you stated. But if you look at what the ground electrode looks like with that gap, you probably would not use them that way. The NGK engineers stated that no spark plug gap should be altered more than 0.006 or you'd be at risk of the ground electrode breaking (chances are greater, but IMHO, not a major issue). More importantly, you are no longer keeping a parallel surface from the center electrode to the ground electrode. Flame travel and the risk of a misfire is greater using the "old skool" 4306 plug. If you compare the two plugs side by side, besides the major appearance difference with the Iridium plug's center electrode, you can visually see that the ground electrode has a shorter reach from the base of the spark plug shell to the bend. Thus giving it a way better and ideal angle between the two electrodes when you are using the tighter .030 gap


    You're paying several thousands of dollars for a turbo system, why be cheap about and extra $40 for the proper spark plugs that at worst gives you the same performance, or at best out performs and out lives an old skool plug?

    Nobody gets outta here ALIVE

    Quote from BKL

    When I went to swap the plugs, I found that Iridium plugs (AC Delco 41-103/12625058) were already installed, presumably by my dealer during a service, or else Polaris actually shipped my Slingshot that way


    From the GM factory that way .........


    Word of caution ... all manufacturers of Ir plugs recommend you not re-gap ... the center electrode laser welded Ir tip is brittle and easily cracked/chipped/broken in ways not visible to the naked eye and can fail in use ... which happened at a high rate when they first came out due to less than gentle re-gapping, giving them an initially bad rep .....




    ..... nerd-squared


    .

    :REDSS: The ghost of SLingshot past ......

    From what I've read, the NGK 4306 plugs seem to work well. I was concerned about how much the 4306 plugs needed to be regapped. According to this site - NGK 4306 LZTR5A-13 Nickel Spark Plug, the 4306 default gap is .050 so reducing that to the Hahn-specified .030 or even .035 seems to be a rather large reduction.
    I carefully followed an NGK video on regapping their Iridium plugs, so I think I did ok and tried my best to not allow the adjustment fingers to touch the center electrode. The AC Delco plugs looked great, so I thought I'd initially try them, although they appeared to be gapped at just under .045. I was just concerned about how compatible they would be compared to the NGK 4306 or 92182. From what I've read, they are all heat range 5.
    I guess to be extra safe, I'l go ahead and install the NGK 92182 plugs since I already have them.