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Old 04-18-2002, 05:38 AM   #1
Scooby Specialist
Member#: 14909
Join Date: Feb 2002
Chapter/Region: BAIC
Location: Bay Area, CA
Question Which NGK iridium spark plug # for 2.5 liter???

I'm sure it's on here somewhere, but I couldn't find it using the search. Also, the NGK part finder is crazy. It shows different plugs for different year 2.5 L engines and I can't find the iridium ones at all, but I know they make 'em for our application.

Anyway, if you know the part number for the correct NGK Iridium plugs for the 2.5, or thing you know of a better plug, please post! Thanks!

Jeremy Siwek
[email protected]
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Old 04-18-2002, 10:32 PM   #2
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Member#: 2060
Join Date: Aug 2000
Chapter/Region: BAIC
Location: Bay Area
00 2.5RS Coupe
01 black boxster hardtop


Do you mean Denso Iridiums?
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Old 04-18-2002, 11:38 PM   #3
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Join Date: Mar 2002
Chapter/Region: MWSOC
Location: Baraboo, WI
2002 WRX Sedan Stg2
2013 OBW roll'n at 30+mpg


I don't know BUT I do know I was quoted $19 EACH for the NGK PFR5-11 "lazer platinum" at my local NAPA...MY2K 2.5l wagon
The heat range should be simmilar "5" or "6"
they have 2 #ing systems NGK says
"B" 14mm thread
"K" 5/8" hex socket w/projected tip
"R" Restior
"5" "6" heat range 6 is safer
"E" 19mm thread reach
"11" 0.44 gap
Contact them for the missing #'s
even cheap Autolite Platniums are better than the JUNK factory "champions" BLAH

Last edited by GLwagon; 04-19-2002 at 12:11 AM.
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Old 04-19-2002, 02:42 AM   #4
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Old 04-19-2002, 12:00 PM   #5
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Location: Newark,NJ,USA
2000 2.5 RS


ohhh...pretty spark plugs, i want plat spark plugs.
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Old 04-19-2002, 12:28 PM   #6
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Member#: 449
Join Date: Oct 1999
Chapter/Region: MWSOC
Location: Lawrence, KS
2016 BRZ Limited
Ice Silver Metallic


Copper conducts better than plat, plat if for people that don't care about performance but longevity and are too lazy to change the plugs more often. Plats are also for people w/ a lot of money I change my plugs every spring, they only cost 1.50 each.

From that NGK link:
Frequently Asked Questions
Q: How much of a performance improvement can I expect from changing plugs?

A: A common misconception is that changing spark plugs will result in a large power increase. In most cases, removing even seriously worn out spark plugs will only result in very modest power gains, typically about 1-2% of total engine output. This could be even less for computer-controlled vehicles, primarily because most newer vehicles have more powerful ignition systems and the vehicle's computer can make adjustments so that vehicle operation seems smoother and more seamless.

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 cars' 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.

When a stock or near-stock engine is given a fresh set of spark plugs, peak efficiency is restored. The power gains that come from this restored state of tune are usually minimal. 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.
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