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Porsche // Cayman 987C / 981C (2005-2016) // Cayman 2.9L 987C MKII 2009-12
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- Porsche 911 1978-1989 3.3L Turbo (930)
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93
- Porsche 928 4.5L 1978-82
- Porsche 928S 4.7L 1981-83
Hose - 4 x 9mm
Sold by the metre
High-quality 4x9mm hose designed for Porsche 911 Turbo (1978–1983), 964 Turbo, and Porsche 928 (1978–1983) models, supplied per metre for precise fitment and flexible installation.
This hose is used within the inlet manifold system,
where it plays a key role in maintaining correct airflow and vacuum balance.
Proper function of this hose is essential for stable engine performance,
efficient combustion, and reliable turbo operation.
Manufactured to OEM specifications, this hose provides durability, flexibility, and resistance to heat and pressure, making it ideal for maintenance, repair, or restoration of Porsche intake systems.
Key Features
• 4mm internal diameter, 9mm outer diameter
• Suitable for Porsche 911 Turbo (1978–1983), 964 Turbo, and 928 (1978–1983)
• Part number 00004320494
• Designed for inlet manifold and intake system use
• Sold per metre for custom length applications
• Resistant to heat and engine bay conditions
• Flexible and durable construction
• OEM-style fit and performance
Function and Purpose
This hose is an important part of the intake system.
It helps to:
• Maintain correct airflow within the inlet manifold
• Regulate vacuum pressure for engine systems
• Support efficient combustion and engine performance
• Prevent air leaks affecting drivability
• Ensure stable turbo and intake system operation
Why Replace Intake Hoses
Over time, intake hoses degrade due to heat and pressure.
Common issues include:
• Cracking or splitting
• Air leaks reducing engine performance
• Hardening and reduced flexibility
• Inconsistent engine operation
Replacing worn hoses restores proper airflow and engine efficiency.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
00004320494
The product you are viewing cross references to these numbers
- Porsche Boxster 987 MKII 2.9L 2009-12
- Porsche Boxster S 987 MKII 3.4L 2009-12
- Porsche Cayman 2.9L 987C MKII 2009-12
- Porsche Cayman S / R 3.4L 987C MKII 2009-12
Fits:
Porsche Boxster 987 MKII 2009-12
Porsche Cayman 987C MKII 2009-12
Click 'Zoom in' for large parts diagram.
Diagram ref no 16
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
98711027030
The product you are viewing cross references to these numbers
- Porsche Boxster 987 MKII 2.9L 2009-12
- Porsche Cayman 2.9L 987C MKII 2009-12
Fits:
Porsche 987.2 Boxster 2.9L 2009-12
Porsche 987C.2 Cayman 2.9L 2009-12
Click 'Zoom in' for large parts diagram.
Diagram ref no 13
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
9A111301802
The product you are viewing cross references to these numbers
- Porsche Boxster 987 MKII 2.9L 2009-12
- Porsche Cayman 2.9L 987C MKII 2009-12
Fits:
Porsche 987.2 Boxster 2.9L 2009-12
Porsche 987C.2 Cayman 2.9L 2009-12
Click 'Zoom in' for large parts diagram.
Diagram ref no 12
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
9A111301702
The product you are viewing cross references to these numbers
.jpg?width=197 "Air Injection Hose. Porsche 987.2 Boxster / Cayman 2.9L 2009-12 - 9A111333900")
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- Porsche Boxster 987 MKII 2.9L 2009-12
- Porsche Cayman 2.9L 987C MKII 2009-12
The Genuine Porsche Air Injection Hose (Part Number 9A111333900) is an original equipment replacement component designed to maintain efficient airflow within the secondary air injection system on selected Porsche Boxster and Cayman models.
Fits:
- Porsche Boxster 987 MKII 2.9L 2009-12
- Porsche Cayman 2.9L 987C MKII 2009-12
Diagram Ref No 10
Manufactured to Porsche's original specifications, this air injection hose provides a secure connection within the secondary air injection circuit, allowing fresh air supplied by the secondary air pump to reach the relevant engine emissions control components.
The secondary air injection system plays an important role in reducing harmful exhaust emissions during engine cold starts. By introducing additional oxygen into the exhaust stream, the system helps promote the oxidation of unburned hydrocarbons and carbon monoxide while supporting faster catalytic converter warm-up.
The air injection hose must maintain an effective connection to ensure the system can deliver the required airflow during operation. Exposure to engine heat, vibration, moisture and repeated temperature changes can gradually weaken the original hose and its fittings.
Over time, the hose may become brittle, cracked, split or detached, allowing pressurised air to escape and reducing the effectiveness of the secondary air injection system. A damaged hose may contribute to increased cold-start emissions, unusual air pump noises or engine management warning lights.
Replacing a worn or damaged air injection hose with a Genuine Porsche component helps restore correct airflow, maintain the integrity of the emissions control system and support reliable engine operation.
Ideal for secondary air injection system repairs, emissions-related fault diagnosis, preventative maintenance and Porsche engine servicing.
What This Product Does:
The air injection hose is a connecting component within the engine's secondary air injection system, which operates primarily during specific cold-start conditions.
Its main functions include:
- Transfers Secondary Air: Carries fresh air from the secondary air injection pump towards the associated air distribution components.
- Supports Cold-Start Emissions Control: Helps supply oxygen to the exhaust system during the engine's warm-up phase.
- Reduces Harmful Exhaust Emissions: Supports the oxidation of unburned hydrocarbons and carbon monoxide during cold starts.
- Assists Catalytic Converter Warm-Up: Helps create conditions that promote faster catalytic converter light-off and effective emissions treatment.
- Maintains Correct Airflow: Provides a sealed passage for the air supplied by the secondary air pump.
- Prevents Air Leakage: Helps prevent the loss of secondary air pressure through damaged connections or deteriorated hose material.
- Accommodates Engine Movement: Allows for normal vibration and small movements between connected engine components.
- Supports Engine Management Operation: Helps the secondary air injection system deliver airflow when commanded by the engine control unit.
- Maintains Factory Emissions Configuration: Replaces the original air injection hose using Porsche's specified component design.
Symptoms Of Wear Or Failure:
The air injection hose operates in a demanding engine compartment environment where heat, vibration and repeated temperature changes can contribute to material deterioration.
Common symptoms of a worn, damaged or leaking air injection hose include:
- Engine Management Warning Light: A secondary air injection system fault may trigger the check engine light.
- Secondary Air Injection Fault Codes: Diagnostic trouble codes relating to insufficient secondary air flow, such as P0410, P0411 or manufacturer-specific equivalents, may be recorded.
- Cracked or Split Hose: Visible cracks, splits or damaged sections of the hose may allow air to escape.
- Brittle or Hardened Material: Ageing and prolonged heat exposure can cause the hose to lose flexibility.
- Loose or Detached Connections: Damaged retaining clips or hose ends may prevent the hose from remaining securely attached.
- Unusual Cold-Start Noises: A leaking or detached hose may produce a hissing or rushing-air sound while the secondary air pump operates.
- Reduced Secondary Airflow: Leaks or restrictions can prevent the correct volume of fresh air from reaching the emissions control system.
- Emissions Test Failure: A malfunctioning secondary air injection system may contribute to emissions-related inspection problems.
- Damaged Hose Fittings: Cracked connectors or worn retaining features may allow air leakage at the connection points.
- Heat or Abrasion Damage: Contact with surrounding engine components may cause chafing, deformation or localised wear.
- Visible Hose Displacement: The hose may no longer follow its original routing or may have become disconnected during previous repairs.
Why Replacement Matters:
Replacing a worn or damaged secondary air injection hose is important for maintaining the correct operation of the vehicle's emissions control system.
Key Benefits of Replacement:
- Restores Secondary Airflow: Helps maintain the intended flow of fresh air through the secondary air injection circuit.
- Reduces Air Leakage: Replaces cracked or damaged hoses that allow pressurised air to escape.
- Supports Cold-Start Emissions Control: Helps the secondary air injection system operate effectively during engine warm-up.
- Protects Emissions System Performance: Supports the intended operation of the catalytic converter warm-up process.
- May Resolve Airflow-Related Faults: Can correct secondary air injection fault conditions where a leaking or damaged hose is confirmed as the cause.
- Maintains Secure Connections: Restores proper hose fitment and retention within the air injection system.
- Reduces Unwanted Airflow Noise: Helps eliminate hissing or rushing-air noises caused by hose leaks.
- Genuine Porsche Quality: Manufactured to the original equipment specifications for the applicable application.
- Correct Factory Fitment: Designed to match the intended hose routing and connection arrangement.
- Supports Long-Term Reliability: Helps prevent recurring problems associated with deteriorated hose material.
- Ideal for Preventative Maintenance: Suitable for replacement when the hose is found to be cracked, damaged or excessively brittle during servicing.
- Supports Emissions Compliance: Helps maintain the factory emissions system in the condition required for correct operation.
Although the secondary air injection hose is a relatively small component, it performs an important role within the vehicle's emissions control system.
A damaged or disconnected hose can interrupt the delivery of secondary air, potentially resulting in increased cold-start emissions and engine management faults.
Replacing the hose with a Genuine Porsche component helps restore the designed airflow path and reduces the risk of continued air leakage.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
9A111333900
The product you are viewing cross references to these numbers