🏁 The Legendary Inline-Six. Finally Breathing Right.

The 4.0L AMC inline-six in your TJ is one of the most beloved engines in American off-road history. Reliable, torquey, and nearly unkillable.

But that factory intake system — a flattened plastic box with a tiny paper filter sitting right in the hot engine bay — was designed for one thing: not breaking.

It was not designed for crawling over rocks, fording streams, or conquering sand dunes.

Flashark's 76mm cold air intake fixes all of that:

→ 76mm smooth-bore aluminum tubing — right-sized for the 4.0L I6
→ Dry high-flow filter — massive surface area vs. factory paper element
→ Heat shield pulls cooler air away from the engine bay
→ Stronger low-end and mid-range torque
→ Throttle response is instant
→ No tune — factory ECU adapts
→ Direct bolt-on in your garage

The 4.0L was built to be off-roaded. Flashark just gives it the air to prove it.

  BEFORE YOU BUY — READ THIS

• Stock ECU / No tune: ✅ Fully compatible (4.0L, 2.4L, and 2.5L all supported)

• Off-road/hard use: ✅ Built for it (heat shield, sealed airbox, dry filter)

• With bolt-ons (exhaust, header): ✅ Gains stack with any performance combo

• With a supercharger: ✅ Works great (The 4.0L I6 handles forced induction well)

• CARB compliance:
  ⚠️  1997-2006 TJ not CARB-exempt for all states. Check the product listing for the CARB EO# before ordering if in CA, NY, or other CARB states.

Technical Specifications

System Type: Cold Air Intake (CAI)
Tubing Material: 6061-T6 Aluminum
Tubing Finish: Polished / Black Powder Coat
Tube Diameter: 76mm (3.0") — large bore throughout (no reducer) matched to 4.0L throttle body
Air Filter: High-Flow Dry Cotton (washable & reusable) No oil required — zero mess
Heat Shield: Included — full enclosure seals filter from the engine bay heat routes to the coolest available air source
MAF Housing: CNC-machined 76mm aluminum precise bore = no CEL on 4.0L I6, 2.4L I4, and 2.5L I4
Couplers: Multi-ply silicone (black) high-temp rated, clamp-sealed
Clamps: Stainless steel T-bolt (all hardware)
Installation: 100% Bolt-On, No welding, no drilling
Hardware: All included

Why Flashark? 5 Reasons

1️⃣  THE RIGHT TUBE FOR THE 4.0L I6

The AMC 4.0L straight-six is a torque machine — it makes peak torque at low RPM and needs air volume throughout the power band.

Flashark's 76mm mandrel-bent tubing:
• Matches the 4.0L throttle body bore
• Smooth interior — no flow turbulence
• Aluminum dissipates heat faster than factory plastic
• No CEL on the AMC/Jeep ECU calibration

→ More torque where the 4.0L makes it: 2,000-4,000 RPM on the trail

2️⃣  DRY FILTER — BUILT FOR OFF-ROAD

Off-roading means dust, dirt, water, and everything in between.

Flashark's dry media filter:
• No oil to attract and hold fine dust
• Wash and reuse — no re-oiling
• Maintains airflow even when loaded with dirt
• Better fine-particle filtration than cotton-oiled alternatives
• Zero risk of oil coating your MAF sensor

For a TJ that actually goes off-road, dry is the right call.

3️⃣  SEALED AIRBOX — WATER & DEBRIS PROTECTED

This is critical for serious off-road use.

Flashark's enclosed airbox:
• Seals the filter from engine bay heat
• Protects filter from direct water splash (stream fordings, heavy rain)
• Blocked from large debris at the air intake
• Keeps the MAF sensor signal clean even in dusty conditions

The airbox enclosure is the difference between a CAI that survives off-road and one that hydrolocks your engine.

4️⃣  NO TUNE. JUST BOLT ON AND GO.

The AMC 4.0L ECU is simple and robust. Flashark's MAF housing gives the Jeep computer exactly what it expects:

→ No check engine light
→ No reflash or tune required
→ All factory systems remain functional
→ 4WD, ABS, OBD-II all unaffected

5️⃣  BOLT-ON IN YOUR DRIVEWAY

Designed for the TJ chassis — every mount point and clamp is an exact fit.

Tools needed: Basic hand tools (ratchet, 10mm/12mm sockets). Estimated time: 60-90 minutes

No cutting. No drilling. Jeep TJ owners have been bolting things on for decades — you know the drill.