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Standard Alternator / Genarator
- Porsche 928 4.5L 1978-82
- Porsche 928S 4.7L 1981-83
- Porsche 928S2 4.7L 1984-86
Alternator 14 Volt 90 Amp
The Porsche Alternator is a high-quality 14 Volt, 90 Amp charging system component designed for Porsche 928 models produced between 1978 and 1984. As a critical part of the vehicle's electrical system, the alternator generates electrical power while the engine is running and continuously recharges the battery to ensure reliable operation of all onboard systems.
The alternator supplies power to essential components
including the ignition system, fuel injection, engine management systems,
lighting, instrumentation, climate control and electrical accessories. Without
sufficient charging output, the battery will gradually discharge, leading to
electrical faults, poor starting performance and eventual vehicle breakdown.
Fastening Type: Single pivoted lever
Pulleys: without belt pulley
Info: with integrated regulator
Rotation Direction: Clockwise rotation
Connector / Clamp without connection for speed sensor
Voltage: 14v
Alternator Charge Current: 90 amp
manufacturer quality: MADE IN GERMANY
For owners of early Porsche 928 models, maintaining a healthy charging system is essential to preserve reliability, performance and the smooth operation expected from Porsche's luxury V8 grand tourer.
What Does an Alternator Do?
The alternator converts mechanical energy from the running engine into electrical energy. Driven by the engine belt system, it continuously generates power to operate the vehicle's electrical systems while simultaneously charging the battery.
The alternator is responsible for:
Charging the battery while driving Supplying power to vehicle electrical systems Maintaining correct system voltage Supporting ignition and fuel injection operation Ensuring reliable engine startingA properly functioning alternator is essential for maintaining stable electrical performance throughout the vehicle.
Symptoms of Alternator Wear or Failure
Alternators operate under constant electrical and mechanical load and are exposed to heat, vibration and age-related wear. Over time, internal components such as bearings, brushes, voltage regulators and rectifiers can deteriorate.
Common symptoms of alternator failure include:
Battery warning light illuminated Flat or repeatedly discharged battery Slow engine cranking Hard starting Flickering or dim headlights Weak dashboard illumination Electrical accessories operating intermittently Low charging voltage Whining, grinding or bearing noises Burning electrical smell Engine stalling caused by low system voltageIn many cases, charging performance gradually deteriorates before complete alternator failure occurs.
Why Alternator Replacement Matters
A failing alternator can leave the battery unable to recharge, eventually resulting in complete loss of electrical power and vehicle breakdown.
Replacing a worn alternator helps:
Restore proper battery charging Prevent unexpected breakdowns Improve electrical system reliability Maintain stable charging voltage Extend battery life Protect sensitive electrical components Eliminate charging system warning lights Ensure dependable vehicle operationFor classic Porsche 928 models, maintaining correct charging voltage is especially important for protecting ageing electrical systems and ensuring long-term reliability.
Features & Benefits
- 14 Volt, 90 Amp output
- Provides reliable battery charging
- Maintains stable electrical system voltage
- Supports ignition and fuel injection systems
- Helps prevent battery discharge
- Durable construction for long service life
- Ideal for maintenance, repairs and restoration projects
Keep your Porsche 928 charging system operating at peak performance with this Alternator
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
92860311401
The product you are viewing cross references to these numbers
- Porsche 928 4.5L 1978-82

Reconditioned Alternator 90amp
Please note:
Reconditioned units are sold on an exchange basis, A surcharge of £175.00 will be held and then refunded when the old one is returned.
Fits:
Porsche Porsche 928 4.5ltr 1978-1982
For vehicles with 12V main current,
Amp: 90 A
Connections: 2 Stud (B+, W) & spade (D+)
Fan And Pulley Type: (E) Fan, single-V fixed pulley
Fixing Points: 2
D+ = Warning Light
Diagram ref no 6
Please note:
Reconditioned Alternators are sold on an exchange basis, A surcharge of £150.00 will be held and then refunded when the old one is returned.
- The surcharge for this reconditioned part will be refunded when the exchange unit is received and approved by us and the relevant manufacturer.
- Please note, surcharge refunds often take an average of 6 to 8 weeks to be approved by the manufacturer.
- Acceptance of the exchange part is at the manufacturer's discretion, based on the part being fit for reconditioning.
- All surcharges and exchanges are subject to our terms and conditions.
PLEASE NOTE:
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
92860311303
The product you are viewing cross references to these numbers
- Porsche 944 2.5L 8V 1982-87
- Porsche 944 2.7L 8V 1988-89
- Porsche 944S 2.5L 16V 1987-88
- Porsche 944S2 3.0L 16V 1989-91
- Porsche 944 Turbo 2.5L 8V 1985-88
- Porsche 944 Turbo 2.5L 8V 1989-91
- Porsche 944 Turbo S 2.5L 8V 1988
- Porsche 968 3.0L 1992-94
- Porsche 968 Sport 3.0L 1994-95
- Porsche 968 CS 3.0L 1993-95
- Porsche 968 Turbo S 3.0L 1993-94
- Porsche 928S4 5.0L 1987-92
- Porsche 928GT 5.0L 1989-91
- Porsche 928GTS 5.4L 1992-95

Reconditioned units are sold on an exchange basis, A surcharge of £125.00 will be held and then refunded when the old one is returned.
Fits:
Porsche 944 1985-96
Porsche 968 1992-96
Porsche 928 1982-96
Please note:
Reconditioned Alternators are sold on an exchange basis, A surcharge of £125.00 will be held and then refunded when the old one is returned.
- The surcharge for this reconditioned part will be refunded when the exchange unit is received and approved by us and the relevant manufacturer.
- Please note, surcharge refunds often take an average of 6 to 8 weeks to be approved by the manufacturer.
- Acceptance of the exchange part is at the manufacturer's discretion, based on the part being fit for reconditioning.
- All surcharges and exchanges are subject to our terms and conditions.
PLEASE NOTE:
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
92860301105
The product you are viewing cross references to these numbers
- Porsche 928S 4.7L 1981-83
- Porsche 928S2 4.7L 1984-86
- Porsche 928S4 5.0L 1987-92
- Porsche 928GT 5.0L 1989-91
- Porsche 928GTS 5.4L 1992-95
Fits:
Porsche 928 1983-95
Diagram ref no 25
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
92860313309
The product you are viewing cross references to these numbers
Standard Output Alternators – Reliable Power Generation for Porsche Vehicles
Standard output alternators are a vital component in your Porsche’s electrical and charging system. They generate the electricity required to power essential systems such as lighting, ignition, infotainment, and battery charging. A dependable alternator ensures your vehicle maintains optimal voltage output, supporting both performance and everyday drivability.
At Design911, we offer a complete range of genuine and manufacturer-quality standard output alternators for Porsche models including 911, Boxster, Cayman, Cayenne, Macan, Panamera and transaxle models. Each alternator is precision-engineered for efficient charging, quiet operation, and long-term durability, delivering the performance your Porsche deserves.
What Do Standard Output Alternators Do?
Alternators play a crucial role in your Porsche’s electrical
system. Their main functions include:
- Generating
electrical power to run engine and vehicle electronics.
- Charging
the battery while the engine is running.
- Regulating
voltage output for consistent electrical performance.
- Powering accessories such as headlights, fans, and infotainment systems.
Standard output alternators provide reliable current for road use, ensuring steady voltage supply without overloading your vehicle’s electrical components.
Why Do Alternators Fail?
Alternators operate under high mechanical and electrical
loads, so over time they can wear or fail due to age, heat, and vibration.
Common causes include:
- Worn
bearings or brushes reducing output efficiency.
- Faulty
voltage regulators causing under- or overcharging.
- Corrosion
or oxidation in internal electrical connections.
- Loose
or slipping drive belts affecting alternator speed.
- Exposure to moisture, oil, or debris damaging internal components.
Symptoms of alternator failure include dimming headlights, electrical malfunctions, dead batteries, or dashboard battery warning lights.
Why Replace a Faulty
Alternator?
A failing alternator can cause serious electrical problems,
leaving you with a drained battery or stranded vehicle. Replacing a weak or
damaged alternator restores proper charging function, ensuring smooth
performance and reliability.
Benefits of replacement include:
- Consistent battery charging and voltage stability.
- Improved performance of all vehicle electronics.
- Prevention of battery drain and starting issues.
- Quiet, efficient, manufacturer-quality alternator operation.
Each alternator in this range is made using high-grade materials and precision-balanced components, ensuring dependable performance, low noise, and strong output for both standard and high-demand driving conditions.
1. What are the signs of a failing alternator in a
Porsche?
Common signs of a bad alternator include dimming
headlights, battery warning lights on the dashboard, slow or
failed engine starts, and unusual whining noises from the engine
bay. You might also notice intermittent electrical issues or a drained
battery, which often indicates the alternator is no longer charging
efficiently.
2. How long should a Porsche alternator last?
A well-maintained alternator in most Porsche models
typically lasts between 60,000 and 100,000 miles, depending on driving
conditions and electrical demand. Regular maintenance of belts and battery
connections helps extend alternator lifespan. If your vehicle is frequently
driven in stop-start traffic or harsh environments, periodic inspections are
recommended.
3. Can I drive my Porsche with a failing alternator?
Driving with a failing alternator is not recommended.
Once the alternator stops generating power, your Porsche will rely solely on
the battery — which can drain quickly. This can lead to engine stalling,
loss of power steering, or total electrical failure. To prevent further
damage, it’s best to replace the alternator as soon as symptoms appear.
4. What causes alternator failure in Porsche vehicles?
Alternator failure can be caused by worn bearings or
brushes, corrosion in electrical connections, a damaged voltage
regulator, or contaminants like oil or moisture entering the
alternator housing. Over time, high temperatures and belt tension can
also reduce efficiency or cause internal damage. Regular servicing helps
identify these issues early.