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I acquired a set of NGK Laser Iridium IFR6T11 (Stock number 4589) spark plugs from Rock Auto.
The reason for NGK's is I am replacing a set of Denso IK20 (Stock number 5304-tapered ground electrode) with NGK tapered ground electrode....or so I thought
The tapered ground electrode configuration offers a slight, noticeable power increase, but does not possess the platinum disc on the ground electrode side so replacement occurs at 20 - 30k miles.vs. 100k for Iridium plugs with platinum disc .
The goal then was to find a tapered electrode design (better spark) but with a platinum disc for longevity..
Rock auto advertises the NGK as having a tapered electrode...(inaccurate) with platinum disc on ground electrode...
I am informed by NGK that Rock Auto's depiction of the NGK plug with tapered ground electrode is inaccurate
The customer service contact at Rock Auto was difficult and failed to acknowledge that I was speaking or that I was holding the non-tapered NGK spark plug in my hand while telling me it was tapered so I terminated the call and contacted NGK. Very helpful people at NGK...
This is information on Denso's Iridium plug with tapered ground electrode... Screen shot of NGK Iridium spark plugs
Rock Auto states NGK Iridium spark plugs have tapered ground electrode...
THIS is not a tapered ground electrode....however excellent replacement for stock spark plugs. The platinum disc is not as pronounced..
The tapeted ground electrode configuration offers a slight, noticeable power increase, but does not possess the platinum disc on the ground electrode side so replacement occurs at 20 - 30k miles.vs. 100k for platinum disc plugs.
Highly unlikely that you'll see any power increase, as even NGK will tell you:
" Many people think that simply supplying more spark to the firing tip can and will combust more fuel. What they don't understand is that most newer car engines are so efficient that they are already burning all of the available fuel. Simply adding more spark voltage can't burn more fuel because there is no more fuel to burn. Any company that tells you that their spark plug will provide significant gains in power in a stock or near-stock engine is making blanket statements that may not be supportable. "
Highly unlikely that you'll see any power increase, as even NGK will tell you:
" Many people think that simply supplying more spark to the firing tip can and will combust more fuel. What they don't understand is that most newer car engines are so efficient that they are already burning all of the available fuel. Simply adding more spark voltage can't burn more fuel because there is no more fuel to burn. Any company that tells you that their spark plug will provide significant gains in power in a stock or near-stock engine is making blanket statements that may not be supportable. "
the hottest burning plug is a copper core..precious metal plugs last longer...trade off they wear out sooner. anyone who puts plugs in because they believe they will gain performance has either been mislead or just chasing a unicorn
I get a kick out of Rock auto's tv ad's. "Every part your car will ever need" yeah right. I'd like to know why half of the listed parts are out of stock for the last 2 years?
I order stuff from Lexus of Atlanta and they have sent me the wrong parts several times. So even the dealer messes things up. I just I rotors and brakes for the GS on Monday and they arrived early this morning and a day early.
I order stuff from Lexus of Atlanta and they have sent me the wrong parts several times. So even the dealer messes things up. I just I rotors and brakes for the GS on Monday and they arrived early this morning and a day early.
I ROTORS? where? they arent on ebay anymore. i bought i rotors for my Ls..cross drilled with pads, 7 years ago,no rust,no cracking and same pads!
It states:"tapered ground electrode to minimize quenching".
Square end ground electrodes are old school... the better performance spark plugs use tapered ends.
If a spark could somehow be placed in the combustion chamber without an intrusive spark plug, then performance gains would be realized..
Here a more trapezoidal shaped ground electrode is used to minimize quenching and shrouding of spark.
I will.ask NGK for data.
So I visit with the Technical support at NGK and he advises me that for LS400 4 valve per cylinder hemispherical configuration on our LS400 that the square tip ground electrode is preferred....
They were not able to refer me to anything to support this contention however 4 valve/cylinder heads have difficulty with swirl of combustion mixture vs. 2 valve/cylinder...
Apparently spark plug optimization varies by type of engine... 4 valve/cylinder, 2 valve/cylinder, direct injection, multi-port injection, etc.
04-25-17, 03:42 PM
Rock auto flunks on NGK spark plug description
