1983 Porsche 928 Performance Parts: Upgrading Your V8 German GT

The 1983 Porsche 928 is a landmark grand tourer, but its original 4.7-liter V8 and chassis can be improved significantly with modern performance parts. Whether you’re after more horsepower, better handling, or sharper braking, the aftermarket offers worthwhile upgrades. This guide covers the most effective and realistic parts for the 1983 928, without hype or overpromises.

Engine Performance Upgrades

Cold Air Intake and Exhaust

Improving airflow is the first step. A high-flow cold air intake replaces the restrictive factory airbox. Brands like K&N or BMC offer direct-fit filters that reduce restriction and add a few horsepower. Pair this with a free-flowing exhaust system. Cat-back systems from Borla or Fabspeed eliminate the stock mufflers’ restriction, improve throttle response, and give a deeper tone. Expect 5–10 hp at the wheels from both combined.

Headers and X-Pipe

Stock exhaust manifolds on the 928 are cast iron and heavy. Aftermarket headers from companies like Steve Timmins or Obie’s 928 Parts replace them with tubular stainless steel, reducing backpressure and weight. An X-pipe crossover after the headers balances exhaust pulses and adds mid-range torque. These parts require professional installation but yield 10–15 hp gains.

Fuel System Upgrades

OEM fuel injectors and fuel pressure regulators are often tired. Replacing with high-flow injectors (e.g., Bosch 30 lb/hr) and an adjustable fuel pressure regulator (e.g., Aeromotive) ensures proper fueling for other modifications. A fuel pump upgrade might be needed if you push past 300 hp.

Ignition and Tuning

Upgrading ignition components – spark plugs, wires, and coils – restores lost power on high-mileage 928s. MSD ignition boxes can improve spark energy. The real power comes from a chip tune. Companies like GIAC or Autothority offer ECU upgrades that adjust fuel and timing maps. For maximum results, a standalone engine management system like Haltech or Motec allows custom tuning, but is expensive.

Suspension and Handling

Springs, Shocks, and Sway Bars

The 928’s suspension can be floppy with age. Lowering springs from H&R or Eibach reduce ride height and improve handling. For shocks, Bilstein sports are a popular choice – they dampen well without being harsh. Heavier front and rear sway bars (e.g., 28mm front/24mm rear from Addco or Tarrett) reduce body roll significantly. The combination transforms the car’s turn-in and stability.

Polyurethane Bushings

Replacing worn rubber bushings with polyurethane (Powerflex or Superpro) tightens the chassis. Focus on control arm bushings, sway bar bushings, and rear subframe mounts. This reduces slop and makes steering more precise without adding NVH.

Steering Rack and Brakes

A steering rack rebuild or replacement with a quicker ratio (if available) can sharpen response. For brakes, cross-drilled or slotted rotors from Brembo or Zimmerman with performance pads (e.g., Pagid or Porterfield) improve fade resistance. Upgrade to braided stainless steel brake lines for better pedal feel.

Cooling and Drivetrain

Radiator and Oil Cooler

The 1983 928 has marginal cooling. An all-aluminum radiator (e.g., CSF or OE replacement) increases capacity and durability. An oil cooler with a thermostat (Setrab or Mocal) helps keep oil temperatures in check during spirited driving.

Limited-Slip Differential and Transmission

An LSD from Guard Transmission or Quaife improves traction out of corners. For automatics, a shift kit or valve body upgrade speeds up shifts. Manual transmission cars benefit from a short shifter (e.g., from 928 Motorsports) and a stronger clutch (e.g., Sachs performance) if torque is increased.

Wheels and Tires

Sticking with the original 16-inch wheels limits tire choice. Moving to 17- or 18-inch wheels (e.g., Porsche Cup replicas or aftermarket from BBS) allows modern performance tires like Michelin Pilot Sport or continental ExtremeContact. Wider tires – 255/40-17 front and 285/35-17 rear – greatly improve grip without rubbing if offset is correct.

Considerations Before Buying

• Condition First: Ensure your 928’s engine, transmission, and chassis are solid before modifying. A well-maintained stock car is faster than a neglected one with parts.
• Budget Realistically: Quality parts for the 928 are not cheap. A full engine rebuild with performance parts can exceed $10k. Set priorities based on driving goals.
• Installation: Many suspension and engine jobs require specialized tools and knowledge. Factor in shop labor costs unless you are experienced.
• Reliability vs. Power: The 928’s weak link is the timing belt. Upgrading to a stronger belt from Gates and replacing tensioners is essential before adding power beyond 350 hp. Also consider an oil cooler to reduce heat buildup.

Final Recommendation

For the 1983 Porsche 928, focus on handling and reliability first. Start with a suspension refresh: lowering springs, Bilstein shocks, poly bushings, and larger sway bars. Then improve engine breathing with an intake and exhaust. If you want more power, add headers, a chip tune, and a limited-slip diff. Avoid extreme boost (supercharging/turbocharging) as it stresses an aging engine. Instead, keep the car naturally aspirated and enjoy improved driving dynamics. Budget $3,000–$5,000 for a well-rounded performance upgrade that respects the 928’s grand touring character.