I4 (Inline 4) Ignition Wires - "IndestructaWires" - Standard, Fiberglass Braid (1200 °F)

Custom-built I4 plug wires designed for strength, heat resistance, and long life in real builds — from daily drivers to off-road rigs and high-heat engine bays.

This listing is the high-temp jacket: woven fiberglass braid (~1,200 °F continuous, ~2,048 °F melt).
If you prefer more flexibility and a wipe-clean surface, see Standard, Silicone-Coated.

Built to Order for Your Engine

Provide your engine and vehicle details (plus any relevant mods). We cut every lead to length, choose the correct boot angles and terminations, and build your set specifically for your application.

Toughness You Can Count On

Standard IndestructaWires are built to survive heat, abrasion, and vibration. The fiberglass braid offers serious heat headroom; ceramic or silicone boots resist burning; and reinforced ends provide lasting strain relief. These are not disposable wires — they’re built for long service life.

Core Options – Your Choice of Performance or Suppression

• 0 Ω Wire Core: Ultra-low resistance (~0.04 Ω/ft) for maximum spark energy. Ideal for performance builds where radios or EFI interference are not a concern.
• ~500 Ω/ft Suppression Core: Provides strong spark energy while reducing EMI/RFI. Recommended for EFI and electronics-sensitive vehicles.

Built as our flagship unshielded high-temp set, Standard IndestructaWires let you choose the core that fits your build, paired with the fiberglass braid for maximum jacket heat margin.

Materials & Construction

• Core: 0 Ω (~0.04 Ω/ft) or suppression (~500 Ω/ft)
• Dielectric Stack: >50 kV breakdown margin
• Jacket: Fiberglass braid (~1,200 °F continuous, ~2,048 °F melt)
• Boots: High-temp silicone (~450 °F) or ceramic (~2,000 °F+)
• Terminations: Stainless terminals matched to your distributor and coil
• Diameter: ~8.5–9.5 mm finished size (varies by core)
• QC: Every set continuity-tested for resistance spec compliance

Best For

• Classic and performance inline 4's with distributors (carb or EFI conversions)
• High-heat bays (long-tube headers, turbo/downpipe proximity, trail heat soak)
• Off-road builds requiring rugged jackets and strain relief
• When EMI control beyond suppression is needed, consider our Shielded line

Options & Upgrades

• Ceramic plug boots for extreme heat
• Color/finish options

What’s Included

• Four custom-cut plug leads
• Coil/HEI lead when applicable
• Dielectric grease packet
• Install guide, QC card, and warranty card

Install Notes

• Maintain at least 1″ clearance from headers or turbos
• Fiberglass braid is stiffer than silicone-glass; plan routing with smooth arcs and avoid sharp edges
• Use looms/stand-offs to keep the jacket off direct metal contact

Warranty & Guarantee

Every Standard IndestructaWires set is backed by a 3-year materials and workmanship warranty (boots, jackets, crimp continuity).

Each set also ships with a documentation pack including:

• Warranty card
• Quick start installation guide
• QC Test Sheet
• Specification sheet for your exact build

We guarantee fitment when you provide your engine and vehicle details. If an issue arises, we correct it quickly and stand behind our work.

View Warranty Info Here

Optional: Quick Measure to Reduce Downtime

Want the best chance of a perfect first fit? If you have a usable set on the engine, pull and measure it before ordering. This helps us match your exact routing and reduces the chance you’ll need to send anything back for resizing. We include a complimentary first-fit adjustment on initial install.

How to measure (5 minutes):

• Label each wire by cylinder (and the coil wire if external)
• Measure center-of-terminal to center-of-terminal following the route you’ll use
• Note plug boot angle (straight, 45°, 90°) and the distributor/coil boot style
• Add any routing notes (loom location, tight spots)
• Snap a photo of your notes and upload at checkout (or email with your order #)
• If your current set fits poorly or is routed wrong, skip this—just give us your engine and details and we’ll build from scratch. Either way, if a lead needs fine-tuning on first install, we’ve got you with a complimentary first-fit adjustment.

Pro tips:

• Use a flexible tape or a string for accurate path length
• Don’t add extra “just in case” slack — we’ll account for strain relief
• All wires will be routed slightly longer than your measurements to ensure proper strain relief and routing

Note:

Distributor-based ignitions only. If your four-cylinder uses coil-on-plug (COP), coil-near-plug (CNP), or distributorless/coil-pack rail (DIS), we do not currently build for it (common on many late-model Honda/Toyota/Nissan/Ford/GM I4s and most VW/Audi I4s after the late ’90s/2000s).

If your ignition uses uncommon or legacy terminals (early Ford rings, marine, industrial, etc.), please contact us before ordering. For one-off builds, send clear photos to confirm compatibility.