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Thread: Spark Plug Gap for Non-Tuned Modded Abarth?

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    Spark Plug Gap for Non-Tuned Modded Abarth?

    So as I dive down the hole of troubleshooting a random stumble/hesitation at high RPM per my thread here (http://www.fiat500usaforum.com/showt...utter-question), I figured I would start from one end and work my way out. By doing so, I am going to order some replacement spark plugs (NGK SIKR9A7 Laser Iridium Spark Plug) to have on hand in case my stock plugs don't look too good (can't see why they shouldn't with just 13,000 miles on them). Either way, for less than $50 I figured it wouldn't hurt.

    But this leads to my next question:

    Stock gap is around .026". But I see that a smaller gap of .023"-.024" is recommended when running a tune. My question is, for those who have mods on their car but no tune (yet), should we go to a smaller gap as well?

    I'm currently running the Madness MaxFlow Intake (soon to install the ATM fenderwell RAM intake in its place), GFB DV+, thermal blanket, and an ATM FMIC. I do plan to go to a tune in the future, just not quite yet. My next upgrade will be the coils, going to the Alpha 4C coil packs. Those may be sooner than later if adjusting/replacing the spark plugs doesn't get rid of this random stumble/hesitation.

    What are the torque specs for the spark plugs? I thought I read somewhere that it is 12 lb/ft. Is that correct?

    And lastly, did I read correctly that you don't use anti-seize on our spark plugs because they are coated?

    Thanks!
    2015 Fiat 500 Abarth (Red Rosso, automatic)
    ATM FMIC
    GFB DV+ Diverter Valve
    Madness Maxflow Intake System
    Sila Concepts Thermal Blanket

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    With less restriction and open spaces to fill compared to the OEM side-mount ICs you could be receiving more boost than the ECU is expecting while ramping and confusing the system? Total guess, still shouldn't affect spark quality though.

    I just added a piggyback and think I need to close my gaps. My SIKR9A7s came in closer to .028" IIRC (just a little bit above .7mm). What is the downside of too small of a gap? At a certain point your spark isn't significant enough to begin detonation but I don't think that tipping point is .005" below stock. I say go for it.

    I had read to use anti-seize but who can trust anything you read on the internet anyways? Over lubricated threads may lead to over-torque. My torque wrench doesn't go low enough, I just used the 1/2 turn recommended on the packaging.

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    Lucky for me have a few different torque wrenches. My smallest once I believe goes down to 120 inch-lbs, or 10 lb/ft.

    My new spark plugs came in. But now I need to get a new set of feeler gauges. I looked all over and couldn't find my current set. It's so rarely used, probably sitting in one of my many tool containers, but I don't want to waste my weekend search for something that will cost me less than $10. I have a cheap spark plug gapper coin, but I am not comfortable using it on these iridium/platinum plugs. I did ever so carefully gave it a try to just measure the current gap of the new plug and I just don't like how it comes it wants to come in contact with the tips as well as questioning the accuracy of it.

    I'll probably close the gap a little more, maybe go to .024" for now. When I add a tune, I will then drop it to .023".
    2015 Fiat 500 Abarth (Red Rosso, automatic)
    ATM FMIC
    GFB DV+ Diverter Valve
    Madness Maxflow Intake System
    Sila Concepts Thermal Blanket

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    Nope, just stick with stock gap. The point of running a smaller gap with a tune is because of the higher boost levels. Boost pressure actually increases the resistance of the air between the electrode and the ground strap, requiring more energy to bridge the gap. Harder on coils, and output energy is often straight up lower.
    2013 Fiat 500 Abarth in Grigio - Veruca
    Mod List -
    Craven Speed Short Shifter + Abarth 595 Pomello Shift Knob + Poly shift linkage bushings
    TurboSmart Wastegate Actuator
    DIY Rear Seat Delete
    EC V2.1 Intake
    Mattjk Tweeter mod
    Otis Tuner Lug Bolts

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    I can share some insight on spark plug installation. New plugs come with a light anti-corrosion oil coating but this won't effect torque settings. The real reason using anti-seize gets controversial is the possible reduction in heat transfer. Most techs drop the torque by 20% to avoid over tightening using anti-seize. Also, any decent plug will have plated threads that won't seize anyway so I just check the gap & follow the torque spec. The "turn 1/2 after finger tight" on the box works well with new plugs but ALWAYS use torque for used plugs with crush washers!

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    So I removed the old plugs for inspection, I will post pictures later. Color wise, they looked decent. Cylinder #2’s plug was the only one with evidence of oil all around the threads, the rest were dry.

    I was surprised at how easily all four broke loose, scary even. Practically no effort as if they weren’t even tightened down. Remove the coil packs was a little disturbing since you have to really pull on them to get them to unsnap from the plugs, which they want to stretch a little when doing so.

    Only 1 out of the 4 was gapped at .026”. 2 of the 4 were gapped between .024” and .025”. 1 of the 4 was gapped at around .022”, I think it was the oil coated one. None smell like fuel. I will measure again when I post pictures.

    I decided to just use the new plugs since I had them. I gapped them to somewhere between .024”-.025”. I used my torque wrench and torqued them down to 12 ft lbs.

    I took it for a test drive and it drove and idled smooth. I took a video doing a 0-70 test run.
    2015 Fiat 500 Abarth (Red Rosso, automatic)
    ATM FMIC
    GFB DV+ Diverter Valve
    Madness Maxflow Intake System
    Sila Concepts Thermal Blanket

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    Neat vid & I can't detect any high rpm and boost misfire BTW, oil works its way up the plug threads from cylinder pressure and should stop with proper torque. Looking forward to your plug pics as I'm just getting into these relatively new engines.

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    Here are some pics of the plugs, left to right as you would be viewing from the front of the car:
    E7FE51B8-F8FC-42FE-B77E-DD1B5634F066.jpg
    BAAC4F0A-6FF2-4562-B8E4-14169EEB9E1E.jpg

    The gaps measured, left to right: .024”, .024”, .022”, .025”
    The color, at least to me, looks normal. So that’s good.

    Cylinder #2’s plug was the only one I saw wear there was oil past the threads:
    6DCB95B9-A6A3-4F47-87DD-5DDB994107A2.jpg

    As as mentioned before, none the spark plugs took any effort to break loose. There was no breaking loose to even speak of, they felt so loose. I am wondering if that is why this plug had oil past the threads.
    Attached Images Attached Images
    2015 Fiat 500 Abarth (Red Rosso, automatic)
    ATM FMIC
    GFB DV+ Diverter Valve
    Madness Maxflow Intake System
    Sila Concepts Thermal Blanket

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    lanssolo (11-21-2017)

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    hi, when I changed my plugs for some reason I expierienced same thing absolutely no effort to remove them and actually 2 were loose, that was my original issue with my car the tips on the plugs were fried as well almost makes me think the factory didnt torque these down properly not knowing for sure if they were the original plugs or not as i am second owner, or there are some real hack mechanics out there that have no clue how to tighten spark plugs, I was expieriencing break up at high rpm

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