http://www.ngksparkplugs.com/techinfo/spark_plugs/partnumberkey.pdf
Geez, the guy asked for specs and all that has been said is babble. specs at NGK.
P=platnium
F=14mm
R=resistor (cuts noise in radio)
6=heat range (2-hot -> 11=cold)
G= fine wire nickel alloy center electrode
11=factory wide gap = 1.1 mm / .44 inch gap
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P=platnium
Z=extended gap
F=14mm
R=resistor
6=heat range
F=tapered seat at firing end construction
11=factory wide gap = 1.1 mm / .44 inch gap
What I see is this but a call to ngK might reaveal more. Both are platinum, 14mm. both are resistor and have the same heat range. The GS one has a shorter insulator with a tip that probably allows room for the glue when it bubbles out at temp. Gap is the same. My guess is that NGK expects the GS plug to tolerate being run at higher RPMs than the L and LS and have suggested to Acura that by using the shorter insulator and center insulator gap they can conduct off the heat generated at contantly higher RPM's without changing the overall heat range of the plug. You'd literally have to talk to a NGK technician to get the fine points. I doubt if I would use a GS plug in an L or LS and vice-versa as there would not be a horsepower gain, this looks like more of a life expectancy issue for the plugs based upon gearing. The L and LS won't spend as much of their life in higher RPMS like the 6 speed gearbox will. That is my opinion. Legends have a pretty good history with plugs. I've read mine a few times and they looked pretty good. If you were going to run at the track on a 200 mile race you might want a colder plug by one but doing so on the street would start it fouling maybe. I would stay with the recomended plug. Too hot a plug and one would start detonation as it would act like a glow plug. Stay with the factory chosen NGK's. Acura has already done the ignition homework by giving us one coil for each cyl. That cut the coil saturation issue most igntions have to deal with.
I don't know if this helps or not but here is an analogy. Early 911's. Porsche went to a colder plug to provide the best plug when racing around or at high speed. Great but it had a tendancy to foul at lower PRM's so all the Porsche 911 owners were driving around in 3rd gear to keep the PRM's up to keep the plugs from fouling around town. Put in a hotter plug and the fouling went away but other problems surfaced at higher RPM. If you look at the two NGK Acura plugs you will see that while both are the same heat range - designed to run at the same temp, the GS one is shorter. My opinion is that this tries to compensate for the PRM issue - ie, the GS engine runs up and down more each time it shifts than the automatic does. As a result, the GS plug is designed to handle a broader environment rather than get into a situation like the 911 which had to reduce the envirnoment by running around in 3rd gear when in town. Putting a GS plug in an LS won't do a thing for performance and putting a LS plug in a GS might cause some overheating and detonation at the highend, especially in states where the octane ratings are lower. When I went to FL I noticed I could buy 93 octane in many states but in states like here in CA, 91 is all we see at the pump anymore and sometimes 90. Legends run a pretty high compression ratio for a stock engine so I'd stay with the factory NGK plugs.
did I need new plugs. It made a huge difference in the engine response all the way from bottom to top!!!
