BMW’s Official Spark Plug Supplier: NGK
Here is something many BMW owners do not know: the spark plugs in your BMW from the factory are made by NGK. BMW does not manufacture spark plugs — they source them from NGK Japan, brand them with BMW part numbers, and sell them at dealer prices. The BMW OEM spark plug for the N55 and S55 engines (part number 12120039634) is the NGK SILZKBR8D8S, also sold under NGK part number 97506 (Laser Iridium).
This means when you choose between “OEM BMW” and “NGK” spark plugs for your N55 or S55, you are largely choosing between packaging and price — not product quality.
NGK SILZKBR8D8S vs BMW 12120039634: Are They the Same?
Yes. The NGK SILZKBR8D8S (part 97506) is the exact same plug as BMW 12120039634. Same iridium centre electrode, same silzium ground electrode, same heat range (8), same thread pitch and reach. They are manufactured at the same NGK facility.
The only difference: the BMW-branded version from a dealer costs C$20–$35 per plug. The NGK-branded version from an aftermarket supplier costs C$12–$18 per plug. For a set of 6 (N55 inline-6), that is C$120–$210 (dealer) versus C$70–$110 (NGK aftermarket) — a significant difference at Canadian prices.
What About “Colder” Step Spark Plugs for N55?
Some N55 owners use a “one step colder” plug — typically the NGK SILZKBR9D8S (heat range 9 instead of 8) for tuned applications. The colder plug removes heat faster from the combustion chamber, which helps prevent detonation under boosted, tuned conditions. For a stock N55, the factory heat range 8 plug is correct. If you have Stage 1 or Stage 2 tune, consult your tuner on whether a colder plug is appropriate.
BMW N55 Spark Plug Service Interval
BMW specifies 60,000 km for spark plug replacement on the N55. Many tuned owners or those with heavy track use replace at 40,000–50,000 km. The iridium electrode wears gradually — you may not notice performance degradation until the plug is very worn, but misfires, increased fuel consumption, and rough idle are all symptoms of overdue plugs.
S55 Spark Plugs (M3/M4 F80/F82)
The S55 engine in the F80 M3 and F82 M4 uses the same NGK SILZKBR8D8S plug. The S55 has 6 cylinders like the N55, but runs significantly higher boost pressure and combustion temperatures. Many S55 owners on track programs elect a 30,000–40,000 km replacement interval to avoid any risk of plug failure under high stress.
Where to Buy BMW N55/S55 Spark Plugs in Canada
Dealer pricing for a set of 6 NGK/BMW plugs is C$120–$210. You can find the same genuine NGK SILZKBR8D8S plugs at aftermarket prices through our shop. We stock the BMW S55 / N55 spark plug set with fast shipping across Canada at competitive CAD prices — no dealer markup.
Installation Tips
- Torque spec: 25 Nm (do not use anti-seize on iridium plugs — it will change the torque spec)
- Gap: pre-gapped from factory at 0.8mm — do not regap iridium plugs
- Use a magnetic spark plug socket to prevent dropping plugs into the well
- Replace all 6 at once — the labour cost of replacing one at a time is wasteful
Browse all BMW maintenance parts at Alpina Motorsports — genuine OEM-spec components, Canadian pricing.
