EMPI 8.5mm HEI Spark Plug Wire Set with Coil Wire — VW Type 1 High-Energy Ignition (00-9442-6)

EMPI 8.5mm HEI-style spark plug wire set with matching coil wire — for high-performance, high-energy ignition systems on VW Type 1 air-cooled engines. The thicker 8.5mm wire diameter, upgraded silicone insulation, and HEI-style boots make this the right wire set for engines running MSD, Crane, Pertronix Ignitor II/III, or other high-output electronic ignition systems. EMPI part #00-9442-6.

Why HEI 8.5mm wires for performance ignition

High-energy ignition systems produce significantly hotter spark than stock points or basic electronic ignition modules. That hotter spark needs thicker, better-insulated wires to deliver the energy to the plug without breakdown, crossfire, or radio interference. Stock 7mm Bosch wires are designed for stock-output coils and don't handle high-energy ignition well over time.

8.5mm wires with silicone insulation hold up to the higher voltage, resist heat breakdown, and don't develop the crossfire that's common between adjacent cylinders when wire insulation starts to fail. The HEI-style boots seal tightly around the spark plug and coil tower, eliminating moisture-induced misfires.

Specifications

• Diameter: 8.5mm (vs. 7mm stock)
• Style: HEI (High Energy Ignition)
• Insulation: Silicone
• Boots: Custom HEI-style spark plug boots, plus matching coil wire boot
• Sold as: Complete set (4 plug wires + coil wire)
• Part number: 00-9442-6

Fitment

• VW Type 1 air-cooled engines running high-output electronic ignition
• VW Beetle, Karmann Ghia, Type 3, Thing
• VW Bus / Transporter through 1971 (Type 1 engine)
• Dune buggies, sand rails, and kit cars with performance ignition setups

Best paired with: MSD ignition boxes, Crane high-energy ignition, Pertronix Ignitor II/III, or any aftermarket coil rated for high secondary voltage. For stock points ignition, standard Bosch wires (#98-9986-B) are correct and these are overkill.

FAQ

Will these work with stock points ignition?
Functionally yes, but you don't need them. Stock points ignition produces moderate spark voltage that standard 7mm Bosch wires handle perfectly. The 8.5mm HEI wires are designed for the higher voltage of performance ignition systems.

Do these reduce radio interference?
The 8.5mm HEI wires include suppression to manage RF interference. They're generally well-behaved with car audio installations, though high-output ignition systems will always produce more RF noise than stock setups.

Will they fit my Type 4 engine?
The fit depends on plug location and distributor cap style. The Type 1 wire set has specific lengths and termination styles for the Type 1 engine layout. For Type 4 (1972+ Bus, 411, 412, Porsche 914), confirm fit before ordering.

Are the boots heat resistant?
Yes. Silicone HEI boots withstand the high temperatures of an air-cooled engine bay far better than rubber boots, which crack and harden over time.

What's the lifespan?
Quality 8.5mm silicone HEI wires typically last 50,000–100,000 miles or 10+ years of moderate use, whichever comes first. Significantly longer than standard 7mm wires under similar conditions.

Do they come with a coil wire?
Yes. The set includes the four spark plug wires plus the coil-to-distributor wire — everything from coil to plug.