NGK Spark Plugs
Since 1936, NGK has manufactured ignition products for street, performance, and racing applications. Today, NGK offers spark plugs for everything from stock-replacement engines to dedicated competition builds. Choose the right plug based on your engine’s requirements, including plug dimensions, NGK spark plug heat range, electrode design, and required gap. Whether you’re replacing an existing plug or selecting one for a race engine, start with a verified application, existing NGK plug number, or your engine builder’s recommendation. Behrent’s Performance Warehouse carries standard, V-Power, and NGK racing spark plugs for a wide range of engine combinations.
Shop NGK Racing and V-Power Spark Plugs
Shop NGK V-Power spark plugs, racing plugs, and stock-replacement options for street, performance, and competition engines. Compare plug dimensions, heat range, electrode and firing-end design, and other application requirements to find the right match for your engine and ignition system.
Item Number: NGKTR5
$3.55
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Item Number: NGKTR6
$3.38
Same Day Shipping If Ordered Before 5pm
Item Number: NGKR6431
$2.72
Usually Ships In 3-5 Business Days
NGK Racing Spark Plugs
NGK racing spark plugs come in multiple heat ranges and configurations for competition engines, including projected and non-projected firing ends, resistor and non-resistor designs, and different thread, reach, and seat specifications. Match the plug to the cylinder head, ignition system, engine combination, and engine builder’s specifications rather than selecting a racing plug by heat range or design alone.
NGK V-Power Spark Plugs
NGK V-Power spark plugs use a V-groove electrode design, while NGK racing spark plugs are built in configurations and heat ranges suited to competition applications. The two aren’t mutually exclusive. Some NGK racing plugs also use the V-Power electrode design. Choose between them based on the engine specifications rather than assuming the more specialized racing plug is always the better choice.
How to Choose the Correct NGK Spark Plug
Start with a verified engine application, your existing plug number, or your engine builder’s recommendation. The correct plug must fit the cylinder head and operate within the engine’s required heat range.
Before ordering, check:
- Thread diameter and reach
- Gasket or tapered seat
- Projected or non-projected tip
- Electrode design
- Resistor or non-resistor configuration
- NGK spark plug heat range
- Required plug gap
- Fuel type and engine modifications, including boost or nitrous
- Ignition-system requirements
- Existing NGK plug or stock number
Understanding NGK Part and Stock Numbers
The letters and numbers in an NGK plug number identify specifications such as the plug family, dimensions, and design, although the meaning varies by NGK numbering system. The separate numerical stock number is used for inventory identification.
Using an NGK Spark-Plug Cross Reference
An NGK spark plug cross reference can help you find an NGK equivalent for another manufacturer’s plug. Compare the thread and reach, seat, heat range, tip configuration, resistor design, and electrode type, then verify the plug for your engine application. Modified racing engines may require a different heat range or gap than a basic cross-reference suggests.
Understanding NGK Spark-Plug Heat Range
Spark plug heat range describes how quickly the plug transfers heat from its firing end into the cylinder head, not the strength or temperature of the spark. With NGK plugs, a higher heat-range number indicates a colder plug, while a lower number indicates a hotter plug. Racing engines with increased cylinder pressure or temperature, including some turbocharged, supercharged, or nitrous combinations, may require a colder plug. Use the heat range specified by the engine builder, tuner, or application rather than applying a universal formula. Stick with the same approved heat range across the engine unless the engine builder specifies different heat ranges for a specialized setup.
NGK Spark-Plug Gap Chart for Racing Applications
There’s no universal NGK spark plug gap chart that provides the correct gap for every racing engine. The proper gap depends on the spark plug, cylinder pressure, ignition system, fuel, and overall engine combination.
| Engine or ignition factor | How it can affect plug-gap requirements | What to verify |
|---|---|---|
| Engine manufacturer or builder specification | Establishes the starting gap for the engine combination | Recommended gap for the specific application |
| Higher cylinder pressure | Can make it more difficult for the spark to jump the gap | Engine-builder or tuner recommendation |
| Turbocharger or supercharger | Increased cylinder pressure may affect the required gap | Gap specified for the boosted combination |
| Nitrous oxide | Increased cylinder pressure and combustion demands may affect gap requirements | Plug and gap specified for the nitrous setup |
| Ignition-system output | Available ignition energy affects the gap the system can reliably fire | Ignition manufacturer’s specifications |
| Magneto ignition | May have application-specific plug and gap requirements | Magneto and engine-builder recommendations |
Some NGK spark plugs come pre-gapped, but the factory gap may not be correct for your specific racing application. Measure every plug before installation and set it to the specification for your engine using a wire-style gap tool, taking care not to damage the center electrode. Correct any ignition or tuning problems rather than changing the specified gap to compensate.
Inspecting NGK Racing Spark Plugs
Inspecting NGK racing spark plugs can reveal signs of fouling, electrode wear, excessive heat, deposits, cracked insulators, physical damage, or gap growth. Read the plugs alongside other tuning data, since fuel, additives, ignition timing, operating time, and engine conditions can all affect their appearance.
Inspect racing plugs regularly and replace them when they show excessive wear, damage, fouling, or no longer meet the required gap. Replacement intervals vary by engine and racing application, so follow your engine builder’s or plug manufacturer’s recommendations.
Frequently Asked Questions About NGK Spark Plugs
When should you use a resistor or non-resistor NGK spark plug?
Use a resistor NGK spark plug when specified for electronic ignition systems and onboard electronics, where the resistor helps suppress electrical interference. Use a non-resistor plug only when the ignition system or engine builder calls for one.
Are NGK spark plugs good for racing?
Yes. NGK offers dedicated racing spark plugs in multiple heat ranges and configurations for competition engines. Choose the plug that matches your engine, cylinder head, and ignition-system requirements.