NGK 91725 Spark Plug

NGK Laser Iridium Spark Plug Overview

The NGK Laser Iridium Spark Plug 91725 is engineered for reliable ignition performance in Mazda MX-5 Miata vehicles. Designed with advanced materials and precise specifications, this spark plug supports efficient combustion and consistent engine operation.

• Iridium center electrode tip for enhanced durability
• Copper core center electrode for improved conductivity
• Standard ground electrode with nickel core material
• Pre-gapped to .052 inches for optimal ignition
• Tapered seat type with 14mm thread diameter and 25mm reach
• Non-removable nut electrical terminal type
• Manufacturer heat range rating of 6
• Hex size of 5/8 inch for installation

Detailed Product Description

The NGK Laser Iridium Spark Plug, part number 91725, features a fine iridium tip on the center electrode, which provides a stable and efficient spark while maintaining long service life. The copper core center electrode enhances electrical conductivity, contributing to improved ignition performance. The ground electrode is constructed with a nickel core and a standard tip design, ensuring consistent spark gap and durability under normal operating conditions. This spark plug comes pre-gapped at .052 inches, matching the specifications required for the Mazda MX-5 Miata engine to optimize combustion efficiency.

The tapered seat design and 14mm thread diameter ensure a secure fit in the cylinder head, while the 25mm reach accommodates the engine’s combustion chamber geometry. The non-removable nut terminal type simplifies installation and connection to the ignition system. With a manufacturer heat range of 6, this spark plug is suited for typical operating temperatures encountered in the MX-5 Miata.

About the Laser Iridium Spark Plug Line

The NGK Laser Iridium Spark Plug line is designed to provide precise ignition performance with enhanced electrode durability. The iridium tip on the center electrode offers a fine point for efficient spark generation, which helps maintain engine responsiveness and fuel efficiency. This product line balances longevity and performance, making it suitable for vehicles like the Mazda MX-5 Miata that require reliable ignition components.

Applications and Problem Solving

• Compatible with Mazda MX-5 Miata models requiring a 14mm spark plug with 25mm reach
• Addresses misfires caused by worn or damaged spark plugs
• Helps improve cold start performance and throttle response
• Reduces fouling and electrode wear for consistent ignition
• Supports stable combustion to minimize engine hesitation

Installation Notes and Tips

• Verify the spark plug gap before installation; factory pre-gap is .052 inches
• Use a torque wrench to tighten to manufacturer specifications to avoid damage
• Ensure the tapered seat is clean and free of debris for proper sealing
• Replace spark plugs in sets to maintain balanced engine performance
• Inspect ignition wires and connectors during installation for optimal electrical contact

Quality Assurance and Warranty

NGK spark plugs, including the Laser Iridium Spark Plug 91725, are manufactured to meet strict quality standards for durability and performance. While specific warranty details may vary, NGK products typically come with a limited warranty against manufacturing defects. Using genuine NGK parts ensures compatibility and reliability for your Mazda MX-5 Miata ignition system.