Upgrade Your Jaguar XJS: Top Parts You Should Consider

By Car Blog Editor -
jaguar xjs

The Jaguar XJS, produced from 1975 to 1996, marked a bold evolution from the E-Type’s raw exuberance to refined grand touring elegance. With its targa-top convertible option, V12 power, and aerodynamic wedge shape, the XJS blended luxury with performance, earning a cult following among collectors. Yet, as these cars approach 50 years old, owners face challenges like electronic gremlins and fuel system woes. Upgrading with high-quality Jaguar XJS Parts can breathe new life into your XJS, enhancing drivability, aesthetics, and value.

This in-depth article explores top upgrade parts for the XJS, categorized for easy navigation. We’ll cover why each matters, installation insights, and cost estimates, helping you prioritize for a transformative build. Whether you’re daily-driving a HE coupe or restoring a Cabriolet, these recommendations will elevate your XJS experience.

Powertrain Enhancements: Reviving the V12 Heart

The 5.3-liter or 6.0-liter V12 is the XJS’s soul, but emissions-era carbs and early EFI can choke its potential.

  1. Fuel Injection Conversion Kits: For pre-1982 cars, switch to electronic fuel injection (EFI) throttle bodies from later models. This delivers smoother power delivery and better cold starts. Gains: 20–30 hp. Cost: $1,500–$2,500. Tip: Remap the ECU for optimal air/fuel ratios.
  2. Performance Camshafts and Valvetrain: Kent Cams profiles increase valve lift for mid-range torque. Pair with uprated springs and followers. Ideal for track days, adding 15–25 hp without major surgery.
  3. Exhaust System Overhauls: Free-flow headers, high-flow cats, and resonated silencers in stainless steel reduce backpressure. The result? A deeper growl and 10–15% efficiency boost. Full system: $1,200–$2,000.
  4. Cooling Upgrades: Electric water pumps and larger intercoolers (for supercharged variants) prevent pinging. Add an oil cooler for sustained high-rev runs.

These mods respect the V12’s character while addressing reliability—expect fewer overhauls.

Suspension and Handling: From Cruiser to Corner-Carver

The XJS’s self-leveling rear suspension is sophisticated but leaks rear air bags and sags without maintenance.

  1. Air Bag Replacements and Compressor Kits: Genuine Jaguar-spec air springs with adjustable height sensors. Add a relay upgrade for faster response. Cost: $400–$800 per side.
  2. Coilover Conversion: De-Dion rear setups with Bilstein dampers and Eibach springs lower the center of gravity. Improves turn-in by 20%. $1,000–$1,800.
  3. Bushings and Control Arms: Polyurethane kits for wishbones and anti-roll bars eliminate flex. Stainless steel arms resist corrosion.
  4. Steering Upgrades: Power-assisted rack rebuilds with quick-ratio gears for precise feedback.

Post-upgrade alignment is key—aim for 1.5° negative camber.

Braking and Wheels: Stopping Power Meets Style

Big brakes match the V12’s thrust, but originals fade under duress.

  1. Brembo or AP Racing Kits: Four-piston calipers with slotted rotors and race pads. Halve stopping distances. $2,000–$3,500.
  2. Wheel and Tire Packages: 17-inch alloys (Ronals or Compomotive) with 245/45R17 rubber. Wider rears enhance grip.
  3. Brake Lines and Fluids: Braided stainless hoses and high-boiling DOT 5.1 fluid for fade-free performance.

Body and Aerodynamics: Timeless Elegance Enhanced

The XJS’s glass roof and buttresses are distinctive, but seals perish and paint fades.

  1. Targa Top Mechanisms: Rebuilt actuators and new fabric tops for leak-free operation. $600–$1,200.
  2. Aerodynamic Spoilers and Diffusers: Subtle front splitters and rear valances reduce lift without altering lines.
  3. Exterior Trim: LED taillight conversions and chrome relay covers for modern safety.
  4. Rust Protection: Waxoyl undercoating and panel plugs.

Interior Refinements: Luxury Reimagined

The walnut dashboards and Connolly leather deserve revival.

  1. Seat Recaro or Leather Re-trims: Bolstered seats with heating elements. $1,500–$3,000.
  2. Infotainment Upgrades: Bluetooth head units disguised as OEM radios, with Apple CarPlay.
  3. Wood Rim Steering Wheels: Momo or Nardi in leather-wrapped walnut.
  4. Carpet and Sound Deadening: Dynamat layers for quieter cabins.

Electrical and Tech: Modern Reliability

Wiring looms crack, and alternators underperform.

  1. LED Lighting Kits: Full interior/exterior swap for efficiency.
  2. High-Output Alternators: 140-amp units for accessories.
  3. ECU Remaps: For post-1989 EFI cars, unlocking hidden power.

Transmission Tweaks: Seamless Shifts

The GM 400 auto or Tremec manual benefits from…

  1. Torque Converters: High-stall for quicker launches.
  2. Clutch Packs: For manuals, uprated for 400+ lb-ft.

The Upgrade Roadmap: Budget and Phasing

Start with powertrain ($3,000–$5,000), then suspension ($2,000+), aesthetics last. Total for a full refresh: $10,000–$20,000, recouped in enjoyment and value.

Conclusion: Your XJS, Elevated

Upgrading an XJS isn’t just maintenance—it’s evolution. With thoughtful Best Jaguar Parts, your grand tourer becomes a timeless thrill machine. Rev it up and let the road unfold.

RELATED ARTICLESMORE FROM AUTHOR