NGK 97506 1 Step Colder Spark Plug – BMW N55/S55/S63
When tuning your BMW N55, S55, S63TU it is recommended to go with 1-step colder spark plugs. We’ve found the NGK 97506 working great when gapped to appropriate spec.
NOTE: S55 OEM plugs are highly prone to cracking even on stock vehicles. Some have used them in the past on their N55 motors without realizing the heat range is identical and they are in fact of worse quality than N55 OEM plugs. We don’t suggest using the S55 OEM plugs when tuning your motors and the NGK SILZKBR8D8S (97506) have been found to be far better.