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Author Topic: Spark Plugs  (Read 172 times)

Offline frasermk5

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Spark Plugs
« on: May 07, 2021, 07:37:25 pm »
Do people usually recommend NGK BKR7EIX plugs for the MK5 GTI? Thinking of these and the R8 coils from awesome GTI but not sure the r8 coils actually do anything, more just for styling?

Offline ROH ECHT

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Re: Spark Plugs
« Reply #1 on: May 08, 2021, 02:01:41 am »
NGK (1675) PFR7S8EG are the current OE plug, but they are platinum center core_have a 1mm center core_and have a 0.031"(0.8mm) gap. They work fine.

NGK (2667) BKR7EIX are highly used; they are Iridium center core and platinum coated ground electrodes_have a 0.6mm center core_and also have a 0.031" (0.8mm) gap. They may last longer than the platinum center electrodes. But if you do not plan on running the plugs more than 50k shouldn't matter which of these two you use.

NGK (4853) PFR7B are a good choice for high boost. They too are a 1mm platinum center core but come with a 0.027" (0.7mm) gap.

There's a new NGK (92400) FR7BHX-S, with a 0.6mm Ruthenium center electrode, may last longer then Iridium ("Difference" pic added below), and they provide a larger kernel at ignition for high boost combustion. They come with a 0.031" (0.8mm) gap...which may not be a problem, since they do arc well.

"Difference" in wear between Iridium and posted by NGK;

R8 coils; are a 5.31 Mohm (resistance) coil...not meant for a long duration during ignition. OE are 3.3 Mohm (refers to secondary winding resistance) and are meant for long duration ignition and quick recovery of voltage, which is meant to provide better fuel burning during combustion.  Some see no problem while using R8 coils. Some find that with R8 coils installed, they need to reduce the plug gaps to 0.024" (0.6mm) or 0.026" (0.65mm). This is due to lack of voltage recovery and the R8 coil unable to reach across the gap for some. What I have seen over the years is R8 coils are chosen for the Red color and for their lower cost. I have not yet seen how they improve ignition. Lower resistance = recharges quickly and produces high voltage to reach across larger plug gaps and burn fuel better.
« Last Edit: May 08, 2021, 04:06:12 pm by ROH ECHT »
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