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Old 09-15-2015, 03:18 PM
StephenVA StephenVA is offline
Join Date: Jun 2013
Location: Virigina, USA
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The recommended gap is .32 for fine wire plugs like Iridium. This plug technology has been coming on strong ever since Champion introduced the H.O.T. plugs way back in early 1990s, that were fine wire with the side electrode back filled with copper so the plugs ran hotter at idle (smoother idle, less fouling, etc) and 200 degrees colder at wide open operations (no detonation due to poor cyl fuel mixtures of the day).

The fine wire plugs like the NGK Iridium IX open up the spark area to allow cleaner firing of the fuel mixture in the cylinder. The end results (as the center electrodes do not wear as fast as the older three and four prong plugs due to the precious metals used) are better tip in acceleration, smoother idle, and some better performance and economy.

With that said ANY plug/brand/configuration that is the right heat range, that fits the hole and will not hit the piston is better than that worn out OE plug at 100K.

Review the plug manufacturer's websites for more info. There are LOTS of errors on vendor websites who distribute or retail plugs. Go to the source of info. Our owners manuals are indeed 15 year old now so they can only show what was available in the year or two before production started.
NGK NGK Spark Plugs USA
Bosch Home | Bosch Auto Parts
Champion Champion Spark Plugs
Stay away from the wacko plug brands you will be happier

For the V8 the NGK Iridium IX installed, provide all the improvements as advertised.

SPECIAL NOTE: Buy a plug gaping tool as plugs are gaped at the factory to something that MAY NOT be your settings and plugs are DROPPED all along the way so who knows what it is when you open the box.

From NGK website
The Spark Plug Serious Enthusiasts Rely On

Designed specifically for the performance enthusiast. Iridium IX® offers extreme ignitability, improved throttle response and superior anti fouling

Fine Iridium tip ensures high durability and a consistently stable spark
Iridium alloy has extremely high melting point, perfect for today’s high-tech, high-performance engines
Trivalent Metal Plating - superior anti-corrosion and anti-seizing properties
Outstanding acceleration, high fuel efficiency and durability
Ultimate design, technology and performance.
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2005 X5 4.8IS
The Blue ones are always FASTER....

Current Garage:
2005 X5 4.8is
2002 M5 TiSilver
2003 525iT
1998 528i
Former Garage Stable Highlights
2004 325XiT Sport
1973 De Tomaso Pantera, L Model
1970 Dodge Challenger T/A 4 sp Alpine White
1970 Dodge Challenger T/A 4 sp GoManGo Green
1971 Dart Sport, “Dart Light” package
1969 Road Runner 383
1968 Ply Barracuda 340S FB Sea-foam Green

Last edited by StephenVA; 09-17-2015 at 09:33 AM.
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