Denso 5309 Spark Plug

Denso Iridium Power Spark Plug 5309

Denso Iridium Power spark plug 5309 is built for BMW ignition service with a fine-wire iridium center electrode and OE-style fitment details. It is a direct choice for BMW Z4, BMW M3, and BMW Z3 applications listed below.

Key Features

• Iridium center electrode tip material for stable spark delivery
• 0.4 mm iridium center electrode for precise ignition performance
• Tapercut and U-groove ground electrode tip design
• Standard ground configuration with nickel ground electrode core material
• Copper center electrode core material for efficient heat transfer
• 5000 ohm resistance
• Pre-gap size: 0.9 mm
• Flat seat type, 12.00 mm thread diameter, 19.00 mm reach, 16.0 mm hex size

Iridium Power Line Details

The Denso Iridium Power line focuses on fine-wire iridium construction for responsive ignition performance and consistent spark characteristics. For BMW owners looking for a spark plug replacement that matches the listed OE-style dimensions, Denso 5309 supports service on select BMW Z4, BMW M3, and BMW Z3 models.

Detailed Description

This Denso spark plug uses an iridium center electrode with a 0.4 mm tip to concentrate the spark and support efficient combustion. The tapercut and U-groove ground electrode design, along with the flat seat and 0.9 mm pre-gap, provides the dimensional setup needed for the specified BMW applications. This part cross-references BMW 12 12 0 022 902 for the same application.

Vehicle Fitment

• Fits 2006-2008 BMW Z4, N/A
• Fits 2001-2006 BMW M3, N/A
• Fits 2002 BMW Z3, N/A

What It Is Used For

• Replacing worn spark plugs that cause rough idle
• Addressing misfire-related drivability concerns
• Restoring weak spark performance during acceleration
• Correcting hard-start conditions tied to ignition wear
• Maintaining consistent combustion in select BMW engines

Installation Notes and Quality Assurance

Verify thread diameter, reach, seat type, and pre-gap before installation to match the engine specification. Confirm the vehicle application against the listed fitment for BMW Z4, BMW M3, and BMW Z3 models before service. Denso manufactures this Iridium Power spark plug to published dimensional and material specifications for the listed applications.