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- Porsche 991.1 Turbo 3.8L (520 Bhp) 2014-16
- Porsche 991.1 Turbo S 3.8L (560 Bhp) 2014-16
Intercooler to Cut-Off Valve Pressure Hoses
These intercooler to cut-off valve pressure
hoses are designed for the Porsche 991.1 Turbo and form an essential part of
the charge air system. They connect the intercooler to the cut-off (diverter)
valve, ensuring controlled airflow and pressure regulation within the turbo
system.
Fits:
- Porsche 991.1 Turbo 3.8L (520 Bhp) 2014-16
- Porsche 991.1 Turbo S 3.8L (560 Bhp) 2014-16
Diagram ref no 5 and 6
In a high-performance twin-turbo engine, managing boost pressure is critical. These hoses allow pressurised air to be routed correctly between components, supporting both performance and system protection.
What These Pressure Hoses Do
These hoses link the intercooler to the cut-off valve, which regulates excess boost pressure when the throttle closes.
They help:
• Maintain stable and controlled boost
pressure
• Allow excess pressure to be safely redirected via the cut-off valve
• Ensure smooth throttle transitions and turbo response
• Support efficient airflow within the charge air system
• Protect turbochargers from pressure surges
A properly functioning hose ensures the turbo system operates smoothly and efficiently.
Why Intercooler to Cut-Off Valve Hoses Fail
Due to their position within the turbo system, these hoses are exposed to high pressure, heat and constant airflow.
Common causes include:
Heat and pressure cycling
Repeated expansion and contraction weakens hose material.
Cracking or splitting
Rubber or reinforced sections can degrade over time.
Boost pressure stress
High boost levels place additional strain on hose walls.
Seal and connection wear
Clamps and joints may deteriorate, leading to leaks.
Symptoms of Failing Pressure Hoses
• Boost leaks or inconsistent turbo pressure
• Hissing noise during acceleration or gear changes
• Reduced engine performance
• Poor throttle response
• Engine warning lights related to boost control
• Increased turbo lag
Replacing worn hoses restores proper boost regulation and system efficiency.
Why You May Need to Replace These Hoses
Restore Boost Control
Ensures the cut-off valve operates correctly under all conditions.
Eliminate Boost Leaks
Prevents pressure loss within the charge air system.
Improve Throttle Response
Supports smooth transitions during acceleration and gear changes.
Protect Turbo Components
Prevents pressure spikes that can damage turbochargers.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99111023
The product you are viewing cross references to these numbers
- Porsche 991.1 Carrera C2 3.4L (350 Bhp) 2012-16
- Porsche 991.1 Carrera C2S / GTS 3.8L (400/430 Bhp) 2012-16
- Porsche 991.1 Carrera C4 3.4L (350 Bhp) 2012-16
- Porsche 991.1 Carrera C4S / GTS 3.8L (400/430 Bhp) 2012-16
- Porsche 958 Cayenne S V6 3.0L Hybrid (380Hp) 2010-17
- Porsche 970.1 Panamera S Hybrid V6 3.0L 2011-13
- Porsche 970.2 Panamera S E-Hybrid V6 3.0L (416Hp) 2014-16
or 
Hella ref no 6PP 009 400-471
Fits:
Porsche 991.1 2013-16
I011 - Special models GTS (991/981)
IX51 - For cars with Powerkit 250kW
Click 'Zoom in' for large parts diagram.
Diagram ref no 23
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
03G906051D
The product you are viewing cross references to these numbers