Swapping out your stock exhaust manifold for headers is a popular modification among car enthusiasts, offering potential gains in horsepower and torque. However, this upgrade often necessitates changes to your ignition system, specifically your spark plug wires. This is because headers typically occupy the space previously held by the stock exhaust manifold, often leading to significant clearance issues with standard plug wires. Choosing the wrong plug wires can lead to misfires, poor performance, and even damage to your engine. This guide will help you navigate the selection process for plug wires designed for header-equipped engines.
Understanding the Challenges of Headers and Plug Wires
The primary challenge posed by headers is their proximity to the spark plug wires. Stock plug wires are often routed in a way that accommodates the stock manifold. Headers, with their more complex and often closer-fitting design, significantly alter this routing. A standard plug wire may simply not fit, or worse, may come into contact with the extremely hot header tubes. This contact can lead to:
- Melting or Degradation: The high temperatures of the header tubes can damage the wire insulation, potentially leading to shorts and misfires.
- Poor Performance: Damaged insulation compromises the signal from the ignition coil to the spark plug, resulting in weak sparks and inconsistent combustion.
- Engine Damage: Severe misfires caused by faulty plug wires can lead to damage to the catalytic converter, or even more serious internal engine damage.
Key Considerations When Selecting Plug Wires for Headers
Several factors should guide your selection of plug wires for a header-equipped engine:
1. Wire Length and Routing:
- Custom Lengths: Many performance parts suppliers offer custom-length plug wires tailored to specific vehicle makes and models, including those with headers. This ensures proper fitment and minimizes the risk of interference.
- Routing: Carefully plan the routing of your plug wires to avoid any contact with the hot header tubes. Use heat shields or separators where necessary to maintain sufficient clearance. Consider using wire looms or protective sleeves to bundle the wires and prevent them from rubbing against each other.
2. Heat Resistance:
- High-Temperature Materials: Opt for plug wires constructed from high-temperature materials like silicone or aramid. These materials can withstand the extreme temperatures generated by headers without degrading.
- Insulation: Pay close attention to the insulation material and its heat rating. A higher heat rating indicates better resistance to the heat generated by the headers.
3. Wire Material:
- Conductivity: The core material of the plug wire affects its conductivity. High-conductivity materials such as copper core wire ensure a strong and reliable spark.
4. Spark Plug Boot Compatibility:
- Proper Fit: Ensure that the spark plug boots at each end of the wire are compatible with your spark plugs. A loose or ill-fitting boot can compromise the integrity of the spark.
5. Manufacturer Reputation:
- Trusted Brands: Choose plug wires from reputable manufacturers known for their high-quality products and durable materials.
Installation Tips for Plug Wires on Header-Equipped Engines
- Consult Instructions: Always refer to the manufacturer's instructions for specific installation guidelines.
- Careful Routing: Take your time routing the wires to avoid contact with the hot header tubes. Secure the wires using heat-resistant clips or straps.
- Proper Torque: Securely fasten the spark plug boots onto both the spark plugs and coil packs. Refer to the manufacturer's torque specifications.
- Visual Inspection: After installation, inspect all wire routing for clearance to ensure no part of the wire touches any hot header tube.
By carefully selecting and installing high-quality, appropriately routed spark plug wires, you can ensure your engine runs smoothly and efficiently even with the added performance potential of aftermarket headers. Remember, this investment in quality components will protect your engine from potential damage caused by heat and poor conductivity.
