Product Overview
HKS Super Fire Racing M35LF Iridium Spark Plug – 50003-M35-LF
The HKS Super Fire Racing M35LF Iridium Conical Spark Plug is a high-performance ignition component developed for compatible performance and tuned engines.
Part of the renowned HKS Super Fire Racing M Series, the M35LF combines a performance-focused ignition design with an iridium centre electrode to provide dependable spark performance under demanding operating conditions.
With its conical seat long-reach configuration, the 50003-M35-LF is designed specifically for engines requiring this style of spark plug. Correct spark plug dimensions, seat type and heat range are essential, so compatibility should always be confirmed before installation.
Whether maintaining a modified road car, upgrading a performance vehicle or replacing existing HKS Super Fire Racing plugs, the HKS M35LF provides a premium ignition solution from one of Japan’s best-known performance tuning brands.
Key Features
- Genuine HKS Super Fire Racing M Series spark plug
- HKS M35 heat rating
- Equivalent to approximately NGK heat range #7
- Iridium centre electrode
- Conical seat design
- Long-reach spark plug
- 14 mm thread diameter
- 25 mm thread reach
- 16 mm hex / wrench size
- Designed for compatible performance and tuned engines
- Suitable for road and performance applications where this specification is required
- Premium replacement or upgrade for compatible ignition systems
- HKS part number 50003-M35-LF
- Sold individually
Technical Specifications
| Specification | Details |
|---|---|
| Brand | HKS |
| Product Range | Super Fire Racing M Series |
| Model | M35LF |
| SKU / Part Number | 50003-M35-LF |
| Spark Plug Type | Iridium |
| Seat Type | Conical Seat |
| Reach Type | Long Reach |
| Thread Diameter | 14 mm |
| Thread Reach | 25 mm |
| Hex / Wrench Size | 16 mm |
| HKS Heat Rating | M35 |
| NGK Equivalent Heat Range | #7 |
| Quantity | 1 Spark Plug |
Why Choose HKS Super Fire Racing Spark Plugs?
HKS is one of the world’s most recognised Japanese performance tuning brands, with decades of experience developing components for tuned and high-performance vehicles.
The Super Fire Racing range is designed for motorists who demand more from their ignition components than a standard replacement spark plug. Selecting the correct spark plug can be particularly important on modified, turbocharged and performance engines where combustion temperatures and cylinder pressures may differ from standard factory conditions.
The M35LF offers a performance-focused solution while retaining a relatively street-friendly NGK #7 equivalent heat range.
Iridium Electrode Technology
Iridium is widely used in premium performance spark plugs because it allows the centre electrode to be manufactured with a fine profile while retaining excellent resistance to high temperatures and electrical erosion.
A concentrated spark discharge can help provide reliable ignition of the air/fuel mixture, making iridium spark plugs a popular choice for modern performance engines.
For modified vehicles, good ignition performance becomes increasingly important as boost pressure, cylinder pressure and engine output increase.
HKS M35 Heat Range – NGK #7 Equivalent
The HKS M35 heat rating corresponds approximately to an NGK #7 heat range.
This makes the M35LF suitable for compatible engines requiring this specific heat range, including many mildly modified or performance-oriented applications.
Spark plug heat range should always be selected according to the engine specification and state of tune. Highly modified engines may require a colder plug, so always follow the recommendations of your engine tuner or vehicle manufacturer.
Conical Seat Long-Reach Design
The 50003-M35-LF uses a specific conical seat long-reach configuration with:
- 14 mm thread diameter
- 25 mm thread reach
- 16 mm hex
These measurements are critical.
A spark plug with the wrong thread reach or seat design can cause poor operation or potentially damage the engine. Please compare your existing spark plug specifications or check the appropriate HKS application guide before ordering.
Suitable for Performance & Tuned Cars
The HKS Super Fire Racing series is popular amongst owners of:
- Japanese performance cars
- Turbocharged vehicles
- Modified road cars
- Fast-road builds
- Track-day cars
- Performance engine builds
- ECU-remapped vehicles
- Increased-boost applications
Compatibility depends on the specific engine and spark plug specification, rather than vehicle brand alone.
Important Fitment Information
Please confirm compatibility before ordering.
Spark plugs must match the required:
- Thread diameter
- Thread reach
- Seat type
- Heat range
- Hex size
- Engine specification
The HKS M35LF is a 14 × 25 mm conical seat long-reach plug with a 16 mm hex and NGK #7 equivalent heat range.
If your vehicle or engine requires a different specification, another HKS Super Fire Racing plug may be more appropriate.
Quantity Required
This listing is for ONE spark plug.
Most engines require multiple plugs, normally one per cylinder.
For example:
- 4-cylinder engine – normally requires 4 plugs
- 5-cylinder engine – normally requires 5 plugs
- 6-cylinder engine – normally requires 6 plugs
- 8-cylinder engine – normally requires 8 plugs
Please select the required quantity when ordering.
Why Buy HKS Performance Parts from Performance Cars Parts UK?
Shop for HKS performance parts in the UK from Performance Cars Parts, supplying premium performance, tuning and replacement components for enthusiast vehicles.
We stock and source performance parts for Japanese, European and modern performance cars, helping enthusiasts find quality components from globally recognised tuning manufacturers.
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