NGK 5509 Spark Plug

NGK 5509 Spark Plug for Porsche 911

The NGK 5509 is a standard spark plug built for select Porsche 911 applications from 1989 and 1992-1998. It uses a copper center electrode, nickel tip materials, and a 5,000 ohm resistor to support stable ignition performance in the specified OE-equivalent design.

Key Features

• NGK Standard Spark Plug, part number 5509
• Fits 1989 Porsche 911 and 1992-1998 Porsche 911
• OE-equivalent design with a 0.032 in. gap noted in fitment
• Copper center electrode core with nickel center tip
• Nickel ground electrode with standard ground configuration
• 3 ground electrodes, flat seat, 14 mm thread diameter
• 5/8 in. hex size and removable nut terminal
• Heat range 7 with .75 in. reach

Product Details

NGK 5509, also identified as BCPR7ET, is part of NGK’s Standard Spark Plug line. NGK has long supplied original equipment spark plugs for domestic and import vehicles in North America, and this plug reflects that OE-focused approach with durable materials and a conventional design. For Porsche 911 owners, the 5509 provides a direct match for the listed model years and supports the ignition requirements called out in the fitment notes.

This part cross-references Bosch 7403 and DENSO Auto Parts 5062 for the same application. Fits 1989 Porsche 911, N/A. Fits 1992-1998 Porsche 911, N/A.

Common Replacement Reasons

• Engine misfire or rough idle
• Hard starting or inconsistent ignition
• Worn or fouled spark plug electrodes
• Reduced throttle response under load
• Service replacement at the OE-recommended interval

Installation Notes

Verify the thread diameter, reach, seat type, and gap before installation. The listed fitment notes specify a 0.032 in. gap and OE-equivalent design for the Porsche 911 applications shown. Use the correct torque procedure for the cylinder head material, and inspect ignition wires, coils, and plug wells during service.

Quality Assurance

NGK is a major OE spark plug supplier with extensive automotive manufacturing experience and broad coverage across automotive, motorcycle, marine, and small engine applications. The 5509 is built to original equipment standards for durability and consistent operation in the listed Porsche 911 fitments.