05-01-2015, 03:25 PM
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Member
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Join Date: Jun 2014
Location: SA, TX
Posts: 6,474
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Quote:
Originally Posted by TiAgX5
Pulling the Bosch+4s and installing NGKs to correct a rough idle and/or poor MPG could be nothing more then a corrective action that does not correct the root cause of the problem.
The NGKs have a much smaller spark gap vs the Bosch 4s (it takes less energy to jump the gap of the NGKs. The root cause could be issues with the ignition components and/or low voltage).
Pros of Bosch +4s......
1) Longer spark gap (better ignition of fuel/air charge).
2) Center electrode unobstructed (flame kernel path travels towards piston center, causing combustion chamber ignition event to occur in a "center/out" pattern. NGKs "shroud" the flame kernel with a "J" electrode, causing the initial flame kernel event to travel toward cylinder wall. Engine dyno tuners have seen 2% hp/tq increases just by plug indexing, turning the plug so the "J" electrode is not between the center electrode and piston center).
3) 4 possible spark paths (slow motion in cylinder camera analysis has show less the 1% "no ignition" events with 4 path plugs, around 3% with single path plugs.
Nothing but good news if your ignition system can jump the longer gaps.
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Just giving you my experience with that particular plug. I've run them in other cars as well with no problems. I hope he (and you) continue to experience no ill affects to running those.
After seeing the number of necessary replacements from the +4's I won't recommend or install them for anything European or even new (within the last 3 years or so). Never seen any problems with NGK Iridiums unless they were just worn out or the car was leaking oil onto them through the valve cover.
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