Spark plugs brand: NGK vs NGK Iridium vs Bosch
 

2005 X5 3.0i 126K miles

NGK BKR6EQUIP
NGK IRIDIUM BKR6EIX
BOSCH FGR7DQP

Which should I use? I see many recommendation for NGK Iridium but someone mentioned the Iridium part cannot touch the connector whatever that means. I thought for spark plugs, you basically remove the old part and screw back the new ones to a proper torque.

Also, are NGK spark plugs made in china?

I just put those iridium ones in my '06 3.0i @ 143k miles. I've heard you shouldn't gap the iridium but I think they come within spec when ordered so not sure it's needed. There's a DIY thread here I used and plenty of other threads on the subject if you do a search:

http://www.xoutpost.com/bmw-sav-foru...m-bkr6eix.html

Not sure the iridium made a difference in performance/mileage but the plugs I pulled out didn't look too bad. My understanding is iridium are recommended as they can provide both longevity and performance whereas platinum plugs don't perform as well and copper plugs don't last as long. But I'm sure there's a lot of guys that know more about this than me.

I just replaced mine with the NGK platinum ones (NGK BKR6EQUIP) as per specifications for the N-62 motor. The OEM bosch plugs I pulled out @ 140,000 kms were a bit sad, but not totally stuffed. Have not noticed any difference in performance or economy (only done 100 kms ago). Changing plugs was not a difficult task at all. I laid out the coils in the order I removed them, so they all went back on the same cylinder. Oh - and by the way, NGK are made in Japan and probably one of the best spark plugs you can get (all my petrol/gas/lpg vehicles, stationary motors and machines have them).

Use these, you will be happier in the long run.

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.
NGK WEBSITE: https://www.ngksparkplugs.com/produc...ugs/iridium-ix

BUY AND USE A GAPING TOOL GAP setting is .032"

Buy the BKR6EIX as it is designed for .032 gap setting
The other part number is BKR6EIX-11 is designed for .044 gap setting

^Single tip NGK iridiums for all of my bimmers as well. Never had a problem.

^I agree with Stephen to check the gap as well out of the box

Thanks for all your input. Youtube videos on replacing E53 spark plugs seem to be for 4.4 engine which requires 8 pcs. Since mine's a 3.0i, I just need 6, correct? Are they located 3 on each side of the engine block when you take the cover off? Just wanted to clarify before ordering.

Yep. It's a straight six with all plugs on the US passenger side after you remove the engine caps, 2 10mm nuts, oil cap, engine cover, connectors and coils (see DIY link I sent earlier). The plugs near the firewall can be a bit tricky - you need a socket extension long enough to get to the plug but not so long that the ratchet hits the overhanging body. I also highly suggest a torque wrench with the new ones to ensure you don't under/over tighten (spec is in DIY; I think 18-20 ft-lbs).

Thank you so kindly!

Yep besides cylinder 6 which is tricky with the length of extension but extremely doable, just take off the engine cover and pop each coil out individually and R&R - spark plugs on these cars are very easy - I'm doing the Iridiums this weekend with new Delphi coils just as preventative spring maintenance at my mileage of 86k and 13 years of age