Bosch 79173 Spark Plug

Bosch Nickel Spark Plug for Porsche Applications

Bosch 79173 is a conventional nickel-copper spark plug built for steady ignition performance and OE-level fitment. It uses a heavy-duty yttrium-enhanced nickel center electrode with a copper core to support longer service life in the Bosch Nickel line.

Compatible With 2002-2008 Porsche 911, 2006-2008 Porsche Boxster, and 2006-2008 Porsche Cayman, this Bosch spark plug is engineered to meet or exceed original equipment specifications for nickel-copper core spark plugs.

Key Features

• Bosch Nickel line spark plug for ignition secondary ignition service
• Part number 79173 for direct catalog identification
• Nickel center electrode tip with copper core construction
• Resistor spark plug with 5000 resistance
• Projected ceramic insulator design
• Flat seat, 14 mm thread diameter, 19 mm reach
• Multiple ground electrode design with 4 ground electrodes
• Pre-gapped at 1.6 for installation consistency
• 16 mm hex size and non-removable nut terminal

Detailed Description

Bosch 79173 is a 4-cycle spark plug designed for Porsche 911, Boxster, and Cayman applications from 2002 through 2008. The nickel-copper construction combines a copper core center electrode with nickel tip materials and a nickel ground electrode core to support reliable spark delivery and stable combustion performance. The resistor design helps control electrical noise in the ignition system, while the projected ceramic insulator supports consistent firing characteristics.

The Bosch Nickel product line focuses on practical OE-style replacement value, and this plug follows that approach with a conventional design, flat seat, 14 mm thread diameter, and 19 mm reach. If you are servicing a Porsche 911, Porsche Boxster, or Porsche Cayman and need Bosch 79173, this plug matches the listed fitment and core construction requirements for those vehicles.

What This Spark Plug Helps Address

• Misfires caused by worn or fouled spark plugs
• Hard starting from weak ignition output
• Rough idle related to inconsistent spark delivery
• Reduced throttle response from degraded plug performance
• Ignition noise concerns in resistor-equipped systems

Installation Notes and Tips

Verify the vehicle application before installation and confirm the specified thread diameter, reach, seat type, and hex size match the cylinder head requirements. Bosch 79173 is pre-gapped at 1.6, but the gap should still be checked against the engine specification before use. Use proper spark plug service procedures to avoid cross-threading and to ensure correct torque during installation.

For Porsche 911, Boxster, and Cayman service, confirm the ignition system condition, coil health, and plug well cleanliness before installing new plugs. This helps ensure the new Bosch spark plug performs as expected after replacement.

Quality Assurance

Bosch manufactures this spark plug to meet or exceed original equipment specifications for nickel-copper core spark plugs. The Bosch 79173 is built with a copper-core center electrode, nickel electrode materials, and a resistor design for consistent ignition service in the listed Porsche applications.