Alternator 12v 75A. Porsche 911 1978-83 (Internal Regulator)  ❭  91160312004

Alternator 12V 75A – Internal Regulator

Restore dependable charging performance with this OEM Supplier 12V 75A Alternator, equipped with an internal voltage regulator. Manufactured by an Original Equipment supplier, this alternator is produced to the same demanding standards as the component originally fitted by Porsche, providing the quality, reliability and fitment expected from factory-specification electrical components.

Fits:

• Porsche 911 1978-1983 3.0L / SC
• Porsche 911 1975-1977 3.0L Turbo (930)
• Porsche 911 1978-1983 3.3L Turbo (930) 

The alternator is one of the most important components of the vehicle's electrical system. While the engine is running, it generates electricity to power essential systems including the ignition, lighting, fuel injection, instruments, heating and ventilation controls, whilst simultaneously recharging the battery. A failing alternator can quickly lead to a discharged battery, poor engine performance and complete electrical failure.

This unit is manufactured for precise fitment and dependable long-term operation, making it an ideal replacement for worn or failed original alternators during routine maintenance or restoration.

What Does the Alternator Do?

The alternator converts mechanical energy from the engine into electrical energy.

Its primary functions include:

• Charging the vehicle battery.
• Supplying electrical power whilst the engine is running.
• Maintaining a stable charging voltage.
• Supporting ignition and fuel systems.
• Powering lighting and electrical accessories.
• Preventing battery discharge during normal driving.

The internal voltage regulator continuously controls the alternator output, ensuring the battery and electrical components receive the correct charging voltage without overcharging.

Why Replace the Alternator?

Alternators are subjected to constant heat, vibration and high rotational speeds throughout their service life.

Common causes of failure include:

• Worn bearings.
• Failed internal voltage regulator.
• Worn brushes.
• Damaged slip rings.
• Internal winding faults.
• Diode pack failure.
• Corrosion.
• Age-related wear.

Replacing a worn alternator restores reliable charging performance and helps prevent unexpected breakdowns.

Symptoms of a Failing Alternator

Common signs include:

• Battery warning light illuminated.
• Battery repeatedly going flat.
• Slow engine cranking.
• Dim or flickering headlights.
• Unstable voltage.
• Electrical accessories operating poorly.
• Intermittent charging.
• Bearing noise from the alternator.
• Burning electrical smell in severe cases.

Ignoring these symptoms can eventually leave the vehicle unable to start once the battery becomes fully discharged.

Important Installation Information

This alternator is suitable for Porsche 911 models (1978-1983) using an internal voltage regulator.

For Porsche 911 turbo 3.0ltr (1975-1977) applications, the following additional components are required:

• Resistor 91164198100 × 1
  
• Air Deflector 91110603305 × 1
  
• Cable Connector 111971511 × 2