RLP Spark Plug Wire Set 8.5mm — Red Silicone Jacket with 90° Boots and Stainless Terminals

RLP's Universal 8.5mm spark plug wire set is a high-temperature, high-strength replacement that delivers improved ignition energy and corrosion-resistant terminals for street-driven vehicles.

This wire set upgrades factory ignition wiring with an 8.5mm conductive core, a rugged fiberglass braid and a glossy red silicone jacket rated to 450°F. Built for universal and custom-fit applications, the set is engineered to meet or exceed SAE performance criteria while offering resistance to moisture, chemicals, and heat. It features 90-degree boots for convenient routing and stainless steel plug terminals for long-term conductivity and corrosion protection.

How does this wire set improve everyday driving performance?

By combining a conductive carbon-black core with 5,000 ohms per foot resistance and a high dielectric EPDM inner layer, more energy reaches the spark plug for a hotter, longer-lasting spark. That improved spark can support smoother idle, firmer throttle response, and more consistent combustion under load.

• Conductive carbon-black core for effective RFI suppression and energy transfer
• 5000 ohms/ft resistance to focus ignition energy at the plug
• Fiberglass braid increases tensile strength and terminal retention
• Stainless steel terminals deliver reliable electrical contact and corrosion resistance

What makes the silicone jacket and construction durable?

The wires are covered in a high-gloss double silicone jacket rated to 450°F, which resists cracking, oil, and chemical exposure better than simpler rubber jackets. Under that jacket, EPDM insulation plus a tightly woven fiberglass braid add mechanical strength and protect core integrity over prolonged heat cycles.

• 450°F-rated silicone resists heat, chemicals and moisture
• Double silicone construction for improved wear life and appearance
• Tightly woven fiberglass braid prevents stretch and improves terminal grip
• EPDM inner insulation maintains dielectric strength at high temperature

Can I use this set on different vehicles and replace part 4041?

Yes — this RLP set is designed as a universal and custom-fit option suitable for many early and late-model cars and trucks. It is offered as a replacement for part number 4041, and its 90° boots help accommodate common routing in crowded engine bays.

• Universal and custom-fit applications for cars and trucks
• Designed to replace part number 4041
• 90° boots aid routing near valve covers and distributor caps
• Pre- and post-HEI-compatible for many ignition systems

What warranty and maintenance should I expect?

RLP backs this wire set with a two-year warranty covering defects in materials and workmanship. Routine inspection for damaged boots, cracked insulation, or loose terminals helps ensure reliable performance over time.

• 2-year limited warranty for manufacturing defects
• Inspect boots and terminals periodically for wear or corrosion
• Replace if insulation is nicked or if spark leakage is detected
• Keep connectors clean and properly seated for best conductivity

Who this is for: Drivers and DIY mechanics who want a durable, street-oriented ignition upgrade that balances performance and reliability. This set suits owners restoring older vehicles, tuning daily-driven cars for better response, or anyone replacing worn OE wires with higher-heat, corrosion-resistant components. If you need universal fitment with robust materials and RFI suppression for everyday road use, this RLP 8.5mm red silicone wire set is built to deliver.