Electronic Fuel Injection Throttle Kits

This is a direct replacement kit for converting your Porsche 964 engine to ITBs 

Kit includes:
6 x Full billet, hard anodised ITB with a stainless steel lever assembly
6 x Thermo barrier gaskets
2 x Fuel rail with mounting hardware
1 x Throttle actuator hard anodised with 2 throttle connection rods manufactured out of stainless steel
1 x Throttle position sensor with mounting hardware
All the needed mounting hardware and fittings.  

ITBs in 2 different sizes:
- Tapered ITB: ∅42mm-∅41,5mm (∅42mm is the butterfly valve size, ∅41,5mm is the intake port diameter)
- Tapered ITB: ∅48mm-∅41,5mm (∅48mm is the butterfly valve size, ∅41,5mm is the intake port diameter) 

All parts of this kit are made out of a single piece 6082 aluminum and are anodized or hard anodized to make them more wear resistant. 

The mounting hardware and other parts are made out of stainless steel, the fuel rails out of 6060 aluminum extrusion profile and come with AN6 ORB connection for the fuel lines. 

The throttle linkages and all mounting hardware are made out of stainless steel and the pivoting points of the throttle linkage are made with ball and socket design for smooth operation. The throttle actuator has a bearing inside for a long lifespan. 

You are also able to use the OEM throttle connection cable but you will need to cut the rigid part at the end of the cable and mount a cable nipple for connecting the cable to the throttle actuator. All aluminum parts of the throttle actuator assembly are manufactured out of 6082 aluminum and are hard anodized.

The levers allow you to adjust and finetune mechanical movement of the ITBs

Fuel injectors, fuel lines, standalone ECU, wire harness are NOT included in the kit but work together 

The Adapt Motorsport GT3 manifold individual throttle body kit enables 996 GT3-style intake manifolds and a resonance flap system to be integrated with an existing ITB-equipped classic Porsche 911 engine. Configurations are available with a PA12 nylon or machined aluminium intake T-piece, with manifold inclusion determined by the selected option.

Fits:
Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
Porsche 911 1978-1983 3.0L / SC
Porsche 911 1984-1986 3.2L
Porsche 911 1987-1989 3.2L G50
Porsche 964 (911) C2 1989-93
Porsche 964 (911) C4 1989-93
Porsche 993 (911) C2 1994-95
Porsche 993 (911) C4 1994-95
Porsche 993 (911) C2S 1994-95
Porsche 993 (911) C4S 1994-95

What This Product Does

This system provides the hardware needed to connect an individual throttle body installation to large-volume GT3 intake manifolds. Its resonance flap assembly, intake T-piece, filter and vacuum-control components form an integrated intake arrangement for a custom classic 911 engine build.

Functions

• Connects compatible GT3 intake manifolds to an existing individual throttle body system
• Supports operation of the supplied intake resonance flap
• Provides filtered air through the included K&N air filter
• Supplies the vacuum hardware, hoses and fittings required for flap control
• Allows a choice of PA12 nylon or machined aluminium intake T-piece

Technical Details

• GT3 manifold port diameter: 49mm
• Reference comparison stated by the manufacturer: standard 964 manifold 43mm and 3.2 manifold 39mm
• Base nylon T-piece manufactured from automotive-grade PA12
• CNC-machined resonance flap assembly uses sealed roller bearings
• AMS machined components have a black anodised finish
• Custom adapter option comprises six machined aluminium adapters made to supplied ITB dimensions

Kit Contents and Options

The base kit contains the intake T-piece, K&N air filter, CNC-machined resonance flap assembly, four resonance-flap and throttle sleeves, six intake-adapter sleeves, hose clamps, vacuum canister, solenoid, check valve, connector kit, mounting hardware, vacuum hoses, fasteners and fittings.

Nylon T-piece configurations are offered with or without a pair of AMS GT3 intake manifolds. Aluminium T-piece configurations use a machined filter adapter matching the resonance flap assembly and are also offered with or without manifolds.

The ITB-to-GT3 adapter set adds six custom aluminium adapters. These require accurate measurements from the individual throttle body installation and are only supplied with the applicable base-kit options; the adapter set is not offered separately.

Why This Kit May Be Required

This kit is intended for engine builds where an existing ITB system is to be combined with GT3-style intake plenums and a controlled resonance flap. Correct measurements, mechanical installation and engine-specific calibration remain essential because throttle body dimensions and modified engine specifications can differ between applications.

FAQs

• Are intake manifolds included?
  Manifold inclusion depends on the selected configuration. Options are available both with and without a pair of AMS GT3 intake manifolds.
• What T-piece materials are offered?
  The system can be configured with an automotive-grade PA12 nylon T-piece or a machined aluminium T-piece and filter adapter.
• Are adapters supplied for the existing throttle bodies?
  Six custom aluminium adapters can be specified, but accurate dimensions from the throttle body kit must be provided for their design and manufacture.
• Can the custom adapter set be ordered separately?
  No. The manufacturer specifies that the adapter set is only supplied with the applicable base-kit configurations.
• Does installation require engine calibration?
  Engine management and fuelling should be configured for the individual engine, throttle bodies and intake arrangement by a suitably experienced specialist.

Rennen ITG Air Filter Assembly - Normal for Rennen by JSR Individual Barrel Throttle Body Upgrades

The Rennen ITG Air Filter Assembly - Normal is a complete induction filtration package designed specifically for use with Rennen by JSR Individual Barrel Throttle Body (ITB) systems. The kit includes premium ITG foam air filters together with the required mounting and securing hardware for installation directly onto the Rennen velocity stacks.

Fits:

• Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
• Porsche 911 1978-1983 3.0L / SC
• Porsche 911 1984-1986 3.2L
• Porsche 911 1987-1989 3.2L G50
• Porsche 964 (911) C2 1989-93
• Porsche 964 (911) C4 1989-93
• Porsche 964 (911) RS 3.6L 1991-93
• Porsche 964 (911) RS 3.8L 1991-93

While Individual Throttle Bodies dramatically improve airflow, throttle response and engine performance, they also require effective filtration to protect the engine from dust, dirt and airborne contaminants. The Rennen ITG Air Filter Assembly provides this protection while maintaining the unrestricted airflow characteristics that make Barrel ITB conversions so desirable.

Designed to integrate seamlessly with the Rennen by JSR induction system, this filter assembly offers an excellent balance between airflow, filtration efficiency and engine protection, making it ideal for fast road, touring and occasional track use.

What Does the ITG Air Filter Assembly Do?

The ITG Air Filter Assembly protects the engine by filtering incoming air before it enters the throttle bodies and combustion chambers.

Its primary functions include:

• Preventing dirt ingestion
• Protecting cylinders and piston rings
• Protecting valves and valve seats
• Maintaining clean airflow
• Supporting engine longevity
• Preserving performance
• Reducing engine wear

The filters allow the engine to breathe freely while preventing harmful contaminants from entering the intake system.

Why Are Air Filters Essential on ITB Systems?

Individual Throttle Bodies are designed to maximise airflow and engine response. Without air filters, debris and contaminants can be drawn directly into the engine.

Proper filtration helps:

• Protect expensive engine components
• Prevent premature cylinder wear
• Maintain engine reliability
• Reduce intake contamination
• Support consistent tuning
• Preserve airflow characteristics
• Improve long-term performance

For road-driven vehicles, filtration should always be considered an essential part of any ITB installation.

Why Choose ITG Foam Filters?

ITG filters are widely recognised throughout motorsport and performance automotive applications for their excellent combination of airflow and filtration efficiency.

Benefits include:

• High airflow capacity
• Excellent filtration performance
• Lightweight construction
• Washable and reusable design
• Motorsport-proven technology
• Long service life
• Consistent airflow characteristics
• Ideal for high-performance engines

The foam filter construction allows superior airflow while maintaining effective protection against airborne contaminants.

Why Are Barrel ITB Upgrades So Popular?

Rennen by JSR Barrel Throttle Bodies provide one of the most exciting induction upgrades available for Porsche engines.

Benefits include:

• Instant throttle response
• Improved airflow efficiency
• Enhanced engine breathing
• Increased power potential
• Exceptional induction sound
• Improved driver engagement
• Greater tuning flexibility
• Stunning engine bay appearance

The addition of the ITG Air Filter Assembly ensures these performance gains can be enjoyed while maintaining essential engine protection.

Why Choose the Rennen ITG Air Filter Assembly?

This kit has been developed specifically to work with Rennen by JSR Barrel ITB systems and velocity stacks.

Benefits include:

• Complete filtration solution
• Includes ITG foam filters
• Includes mounting and securing hardware
• Direct fitment to velocity stacks
• Maintains unrestricted airflow
• Protects engine internals
• Suitable for road and track applications
• Professional installation finish       

Rennen ITG Air Filter Assembly - Rally for Rennen by JSR Individual Barrel Throttle Body Upgrades

The Rennen ITG Air Filter Assembly - Rally is the ultimate filtration solution for Rennen by JSR Individual Barrel Throttle Body (ITB) conversions. Designed for demanding road, rally, touring and motorsport applications, this upgraded filtration package combines premium ITG foam filters with enhanced sealing technology and dedicated mounting hardware to provide superior engine protection in dusty and challenging operating environments.

Fits:

• Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
• Porsche 911 1978-1983 3.0L / SC
• Porsche 911 1984-1986 3.2L
• Porsche 911 1987-1989 3.2L G50
• Porsche 964 (911) C2 1989-93
• Porsche 964 (911) C4 1989-93
• Porsche 964 (911) RS 3.6L 1991-93
• Porsche 964 (911) RS 3.8L 1991-93

Like the standard ITG Air Filter Assembly, the Rally version includes high-performance ITG foam filters and all the required hardware for secure installation onto the velocity stacks. However, the Rally specification takes protection one step further with a more robust construction and improved sealing against airborne dust and contaminants.

For owners operating their Porsche in rally, endurance, touring or harsh road conditions, the Rally Air Filter Assembly provides additional peace of mind without compromising the airflow and throttle response benefits of the Rennen by JSR Barrel ITB system.

What Does the Rally ITG Air Filter Assembly Do?

The Rally Air Filter Assembly filters incoming air before it enters the throttle bodies and combustion chambers.

Its primary functions include:

• Preventing dust ingestion
• Protecting cylinders and piston rings
• Protecting valves and valve seats
• Reducing intake contamination
• Supporting engine longevity
• Maintaining airflow efficiency
• Preserving engine performance

The enhanced sealing design provides an additional layer of protection in environments where airborne dust and debris are more prevalent.

Why Are Air Filters Essential on ITB Systems?

Individual Throttle Bodies significantly increase airflow potential and engine responsiveness. However, without effective filtration, harmful particles can enter the engine and cause accelerated wear.

Proper air filtration helps:

• Protect expensive engine components
• Reduce internal engine wear
• Maintain tuning consistency
• Protect piston rings and cylinder bores
• Improve long-term reliability
• Preserve engine performance
• Reduce maintenance costs

For road and motorsport applications alike, high-quality air filtration should always be considered an essential part of any ITB installation.

Why Choose the Rally Version?

The Rally Air Filter Assembly has been developed for environments where maximum engine protection is required.

Compared to the standard filter assembly, the Rally version offers:

• Improved sealing against dust ingress
• More robust filter mounting arrangement
• Enhanced durability
• Greater protection in harsh environments
• Improved filtration security during prolonged use
• Ideal for rally, touring and endurance applications
• Additional confidence for high-value performance engines

This makes it the preferred option for owners seeking maximum engine protection without sacrificing performance.

Why Choose ITG Foam Filters?

ITG filters are widely respected throughout motorsport and performance automotive applications for their ability to combine high airflow with exceptional filtration efficiency.

Benefits include:

• High airflow capacity
• Excellent filtration performance
• Washable and reusable design
• Lightweight construction
• Motorsport-proven technology
• Long service life
• Consistent airflow characteristics
• Suitable for high-performance engines

The foam construction provides outstanding protection while supporting the airflow demands of Individual Throttle Body systems.

Why Are Barrel ITB Upgrades So Popular?

Rennen by JSR Barrel Throttle Bodies provide one of the most exciting induction upgrades available for Porsche engines.

Benefits include:

• Instant throttle response
• Improved airflow efficiency
• Increased engine breathing capacity
• Greater power potential
• Enhanced torque delivery
• Exceptional induction sound
• Motorsport-inspired driving experience
• Stunning engine bay presentation

The Rally Air Filter Assembly ensures these benefits can be enjoyed while providing enhanced protection for valuable performance engines.

Why Choose the Rennen ITG Rally Air Filter Assembly?

Developed specifically for Rennen by JSR Barrel ITB systems, this filtration package offers the ideal balance between airflow, protection and durability.

Benefits include:

• Enhanced dust sealing
• Premium ITG filtration technology
• Complete installation solution
• Includes mounting and securing hardware
• Maintains unrestricted airflow
• Protects engine internals
• Suitable for road, rally and motorsport use
• Professional installation finish       

Rennen MAP Sensor for Rennen by JSR Individual Barrel Throttle Body Upgrades

The Rennen MAP Sensor is a critical engine management component designed specifically for use with Rennen by JSR Individual Barrel Throttle Body (ITB) upgrades. Working alongside the Rennen Vacuum Manifold system, the MAP (Manifold Absolute Pressure) Sensor provides the engine control unit (ECU) with accurate engine load data, allowing precise fuel and ignition calculations throughout the entire rev range.

Fits:

• Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
• Porsche 911 1978-1983 3.0L / SC
• Porsche 911 1984-1986 3.2L
• Porsche 911 1987-1989 3.2L G50
• Porsche 964 (911) C2 1989-93
• Porsche 964 (911) C4 1989-93
• Porsche 964 (911) RS 3.6L 1991-93
• Porsche 964 (911) RS 3.8L 1991-93

When converting a Porsche engine to Individual Barrel Throttle Bodies, the original intake and airflow characteristics change significantly. Unlike conventional plenum intake systems, individual throttle bodies generate multiple pulsing vacuum signals which must be stabilised and measured correctly. The Rennen MAP Sensor, combined with the Rennen Vacuum Manifold, delivers the accurate load signal required for modern ECU calibration and reliable engine operation.

Whether you are building a fast road Porsche, a track-focused machine or a competition engine, the MAP sensor is one of the most important components in ensuring your ITB conversion performs exactly as intended.

What Does a MAP Sensor Do?

MAP stands for Manifold Absolute Pressure.

The sensor continuously measures the vacuum and pressure levels within the intake system and sends this information to the ECU. The ECU then uses this data to calculate engine load and make real-time adjustments to fuel delivery and ignition timing.

A properly functioning MAP sensor helps provide:

• Accurate engine load measurement
• Precise fuel mapping
• Optimised ignition timing
• Stable idle quality
• Improved throttle response
• Enhanced drivability
• Reliable cold starting
• Consistent engine performance

Without a stable and accurate MAP signal, modern engine management systems cannot correctly determine engine operating conditions.

Why Is a MAP Sensor Essential for ITB Conversions?

Individual Throttle Body systems dramatically improve airflow and throttle response, but they also create unique tuning challenges.

Unlike a traditional intake manifold, each throttle body generates its own vacuum pulse. The Rennen Vacuum Manifold combines these signals into a smooth vacuum source which the MAP sensor can accurately measure.

This allows:

• Standalone ECUs to calculate engine load correctly
• More accurate fuel delivery
• Improved ignition control
• Stable idle operation
• Better low-speed drivability
• Enhanced throttle transitions
• Improved tuning consistency

The result is an ITB-equipped Porsche that not only sounds incredible but also drives smoothly and predictably.

Why Are Barrel ITB Upgrades So Popular?

Rennen by JSR Barrel Throttle Bodies are engineered to maximise airflow while delivering a motorsport-inspired driving experience.

Benefits include:

• Instant throttle response
• Improved engine breathing
• Increased power potential
• Enhanced torque delivery
• Exceptional induction sound
• Improved driver engagement
• Modern EFI compatibility
• Stunning engine bay appearance

When paired with a properly calibrated ECU and accurate MAP sensor data, the system delivers both performance and drivability.

Why Choose the Rennen MAP Sensor?

Developed specifically for Rennen by JSR ITB applications, this sensor provides the accuracy and reliability required for professional-level engine management calibration.

Benefits include:

• Accurate vacuum and pressure measurement
• Compatible with Rennen Vacuum Manifold systems
• Supports standalone ECU installations
• Essential for ITB engine management
• Improves tuning accuracy
• Enhances drivability
• Suitable for road and motorsport applications
• Reliable long-term performance       

Cam Position Sensor Mounting Bracket for ITB Conversions

The Rennen Cam Position Sensor Mounting Bracket is a precision-engineered component designed specifically for Porsche 911 and Porsche 964 Individual Throttle Body (ITB) conversions. Developed to provide a secure and accurate mounting location for a cam position sensor, this bracket enables modern engine management systems to utilise camshaft position data for improved ignition timing, fuel delivery and overall engine control.

Fits:

• Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
• Porsche 911 1978-1983 3.0L / SC
• Porsche 911 1984-1986 3.2L
• Porsche 911 1987-1989 3.2L G50
• Porsche 964 (911) C2 1989-93
• Porsche 964 (911) C4 1989-93
• Porsche 964 (911) RS 3.6L 1991-93
• Porsche 964 (911) RS 3.8L 1991-93

As Porsche enthusiasts increasingly move towards advanced EFI and standalone ECU systems, accurate engine position monitoring becomes critical. The cam position sensor mounting bracket provides the stability and precision required to ensure reliable sensor operation in both high-performance road and motorsport applications.

Designed to integrate seamlessly with Rennen by JSR ITB systems, this bracket helps unlock the full potential of modern engine management while preserving the character of the classic air-cooled Porsche engine.

What Does a Cam Position Sensor Mounting Bracket Do?

The mounting bracket securely positions the camshaft position sensor relative to the engine's camshaft trigger reference point.

This allows the ECU to accurately determine camshaft position and synchronise critical engine functions, including:

• Sequential fuel injection
• Sequential ignition control
• Accurate engine timing calculation
• Cylinder identification
• Advanced ECU tuning strategies
• Improved engine management precision

Without a stable and accurately positioned sensor mount, the ECU may struggle to maintain consistent timing and engine synchronisation.

Why Is a Cam Position Sensor Important?

Modern engine management systems rely on precise engine position information to optimise performance.

Cam position data helps provide:

• Improved ignition accuracy
• More precise fuel delivery
• Enhanced engine response
• Improved idle stability
• Better cold-start performance
• Greater tuning flexibility
• Optimised engine efficiency
• Support for advanced ECU functionality

For high-performance Porsche engine builds, accurate camshaft position monitoring is often essential for extracting maximum performance and drivability.

Why Is an ITB Upgrade So Appealing?

Individual Throttle Body systems are widely regarded as one of the most desirable naturally aspirated performance upgrades available for Porsche engines.

Unlike conventional intake systems, ITBs provide each cylinder with its own dedicated throttle body, dramatically improving airflow characteristics and throttle response.

Benefits of a Rennen by JSR ITB conversion include:

• Instant throttle response
• Improved engine breathing
• Increased airflow efficiency
• Enhanced induction sound
• Greater tuning flexibility
• Improved driver engagement
• Increased performance potential
• Motorsport-inspired engine character

When combined with modern EFI and engine management systems, ITBs deliver a unique driving experience that blends classic Porsche character with modern performance technology.

Why Choose the Rennen by JSR Cam Sensor Bracket?

A precision-engineered sensor mounting solution is critical for accurate ECU operation.

Benefits include:

• Secure sensor mounting
• Accurate sensor positioning
• Improved ECU signal reliability
• Enhanced engine management performance
• Greater tuning accuracy
• Improved engine synchronisation
• Reliable operation in road and motorsport environments
• Professional-quality installation       

Crankshaft Position Sensor Mounting Bracket for ITB Conversions

The Rennen Crankshaft Position Sensor Mounting Bracket is a precision-engineered component developed specifically for Porsche 911 and Porsche 964 Individual Throttle Body (ITB) conversions. Designed to provide accurate and stable mounting of the crankshaft position sensor, this bracket enables modern engine management systems to monitor crankshaft position and engine speed with exceptional precision.

Fits:

• Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
• Porsche 911 1978-1983 3.0L / SC
• Porsche 911 1984-1986 3.2L
• Porsche 911 1987-1989 3.2L G50
• Porsche 964 (911) C2 1989-93
• Porsche 964 (911) C4 1989-93
• Porsche 964 (911) RS 3.6L 1991-93
• Porsche 964 (911) RS 3.8L 1991-93

As Porsche performance builds increasingly adopt standalone ECUs and modern EFI systems, accurate crankshaft position data has become essential for reliable ignition timing, fuel delivery and engine synchronisation. The Rennen by JSR mounting bracket ensures the crankshaft sensor remains securely positioned in relation to the trigger wheel, providing a clean and consistent signal under all operating conditions.

Whether building a fast-road Porsche, a high-performance air-cooled engine or a dedicated motorsport application, this bracket forms a critical part of a professional EFI and ITB conversion.

What Does a Crankshaft Position Sensor Mounting Bracket Do?

The crankshaft position sensor mounting bracket securely locates the crankshaft sensor in the correct position relative to the trigger wheel mounted on the engine.

This allows the ECU to accurately monitor:

• Crankshaft position Engine speed (RPM)
• Ignition timing reference
• Fuel injection timing
• Engine synchronisation
• Advanced ECU control functions

A stable and accurately positioned sensor is critical for reliable engine operation and precise ECU calibration.

Why Is a Crankshaft Position Sensor Important?

The crankshaft position sensor is one of the most important inputs used by a modern engine management system.

Without an accurate crankshaft signal, the ECU cannot reliably control ignition or fuel delivery.

Benefits of accurate crankshaft position monitoring include:

• Precise ignition timing
• Accurate fuel injection control
• Stable engine operation
• Improved starting performance
• Enhanced throttle response
• Greater tuning flexibility
• Improved engine efficiency
• Reliable high-RPM performance

For performance-oriented Porsche engine builds, accurate crankshaft data forms the foundation of effective ECU control and engine tuning.

Why Is an ITB Upgrade So Appealing?

Individual Throttle Body systems are widely regarded as one of the most exciting naturally aspirated performance upgrades available for Porsche engines.

By providing each cylinder with its own dedicated throttle body, airflow restrictions are reduced and throttle response is dramatically improved.

Benefits of a Rennen by JSR ITB conversion include:

• Immediate throttle response
• Improved airflow efficiency
• Enhanced engine breathing
• Increased performance potential
• Greater tuning flexibility
• Distinctive induction sound
• Motorsport-inspired engine character
• Increased driver engagement

When paired with modern EFI and engine management systems, ITBs offer a unique blend of classic Porsche character and modern performance technology.

Why Choose the Rennen by JSR Crank Sensor Bracket?

A precision-engineered crankshaft sensor mounting solution is essential for reliable ECU operation.

Benefits include:

• Accurate sensor positioning
• Stable trigger wheel alignment
• Consistent ECU signal quality
• Improved ignition timing accuracy
• Enhanced engine management reliability
• Professional EFI conversion installation
• Suitable for road and motorsport applications
• Supports advanced engine tuning strategies       

Rennen ITG Plenum Flange Set for Rennen by JSR Individual Barrel Throttle Body Upgrades

The Rennen ITG Plenum Flange Set is a precision-engineered conversion solution designed specifically for Rennen by JSR Individual Barrel Throttle Body (ITB) systems. These bespoke flanges attach directly to the top of the Rennen Barrel Throttle Bodies and provide a secure mounting platform for an intake plenum chamber, replacing the traditional velocity stack arrangement.

Fits:

• Porsche 911 1984-1986 3.2L
• Porsche 911 1987-1989 3.2L G50
• Porsche 964 (911) C2 1989-93
• Porsche 964 (911) C4 1989-93
• Porsche 964 (911) RS 3.6L 1991-93
• Porsche 964 (911) RS 3.8L 1991-93

Plenum Inlet Diameter Options:

48mm – suitable for Porsche 3.2ltr, 3.5ltr and 3.6ltr engines
50mm – suitable for Porsche 4.0ltr engines.

Please note:
Plenum adaptor flanges are not available for 2.7 or 3.0ltr engine applications.

Supplied complete with the required mounting and securing hardware, the flange set allows engine builders and tuners to configure their induction system for plenum operation while retaining all the airflow benefits of the Rennen Barrel ITB architecture. Please note that the plenum chamber itself is not included.

This system is ideal for builders seeking alternative intake packaging solutions, improved intake air management, advanced engine management strategies or custom naturally aspirated and forced induction applications.

What Does the ITG Plenum Flange Set Do?

The flange set creates a mounting interface between the Barrel Throttle Bodies and a plenum chamber.

Its primary functions include:

• Providing secure plenum mounting
• Replacing traditional velocity stacks
• Creating a sealed induction system
• Supporting custom intake configurations
• Improving intake packaging options
• Allowing integration with plenum-based induction systems
• Supporting advanced engine management strategies

The flanges form the critical connection point between the throttle bodies and the plenum assembly.

Why Use a Plenum Instead of Velocity Stacks?

Velocity stacks are ideal for maximising throttle response and creating the classic ITB appearance. However, some applications benefit from using a plenum chamber.

Advantages of plenum systems include:

• Controlled intake air supply
• Improved intake packaging flexibility
• Easier integration with air filter systems
• Reduced intake noise
• Consistent air distribution
• Improved airflow management
• Greater flexibility for custom engine builds

The choice between velocity stacks and a plenum depends on the engine's intended use and performance objectives.

Why Is the Plenum Flange Set Important?

Without the correct mounting solution, a plenum cannot be securely attached to the throttle body assembly.

The Rennen ITG Plenum Flange Set provides:

• Correct fitment to Rennen Barrel ITBs
• Reliable sealing surfaces
• Secure plenum attachment points
• Professional installation quality
• Simplified custom intake fabrication
• Compatibility with bespoke induction systems
• Long-term durability

The flange set is the foundation of any successful plenum-based ITB installation.

Why Are Barrel ITB Upgrades So Popular?

Rennen by JSR Barrel Throttle Bodies are designed to maximise airflow and engine responsiveness while offering exceptional tuning flexibility.

Benefits include:

• Instant throttle response
• Increased airflow efficiency
• Enhanced engine breathing
• Greater power potential
• Improved torque characteristics
• Exceptional tuning capability
• Motorsport-inspired engineering
• Stunning engine bay presentation

The Plenum Flange Set expands these possibilities by allowing the induction system to be tailored to the specific requirements of the engine build.

Why Choose the Rennen ITG Plenum Flange Set?

Developed specifically for Rennen by JSR ITB systems, these flanges offer a professional and reliable solution for plenum-based induction conversions.

Benefits include:

• Precision-engineered fitment
• Direct compatibility with Rennen Barrel ITBs
• Complete mounting hardware included
• Supports custom plenum installations
• Professional installation solution
• Durable construction
• Suitable for road and motorsport applications       

Rennen ITBs for Air-Cooled Porsche 964 - Advanced Roller Barrel Individual Throttle Bodies 

The Rennen ITBs by JSR represent the next generation of individual throttle body technology for air-cooled Porsche 964 engines. Designed and engineered specifically to extract optimal performance from classic Porsche flat-six engines, these innovative roller barrel throttle bodies deliver exceptional airflow, sharper throttle response, and improved engine efficiency compared to conventional butterfly valve throttle body systems.

Fits:

• Porsche 964 (911) C2 1989-93
• Porsche 964 (911) C4 1989-93
• Porsche 964 (911) RS 3.6L 1991-93
• Porsche 964 (911) RS 3.8L 1991-93

Developed through extensive research, flow simulation analysis and real-world testing, the Rennen ITB system provides a premium induction solution for performance-focused Porsche enthusiasts, restorers, track-day drivers and motorsport applications.

Whether you are building a high-performance Porsche 911 engine or converting a classic air-cooled Porsche to modern EFI, Rennen ITBs by JSR offer a significant advancement in intake technology.

Why Choose Rennen Roller Barrel ITBs?

Unlike traditional individual throttle bodies that utilise a butterfly valve positioned directly in the airflow path, the Rennen ITB system features a precision-engineered tapered roller barrel design.

This innovative approach provides several key advantages:

Unrestricted Airflow

The roller barrel design eliminates the butterfly valve obstruction found in conventional throttle bodies. With no throttle plate disrupting airflow, air moves more efficiently into the engine, improving volumetric efficiency and overall performance.

Increased Air Velocity

Because there is no butterfly valve occupying space within the throttle bore, the throttle body diameter can be optimised to maintain higher air velocity. Higher intake air speed promotes superior cylinder filling and enhanced engine response throughout the rev range.

Superior Fuel Atomisation

At partial throttle openings, airflow passes directly over the fuel injector. This promotes exceptional atomisation of the air-fuel mixture, improving combustion efficiency, drivability and throttle progression.

Instant Throttle Response

The short distance between the roller barrel and the inlet valve creates a highly responsive induction system, delivering immediate engine response and a direct connection between driver input and engine output.

The ITB kit comes with the ITBs mounted on intake manifolds and with fuel rails made for the EV6 injector type. 

Advanced Flow Simulation & Development

Extensive computational fluid dynamics (CFD) analysis and development testing have been carried out to optimise every aspect of the Rennen ITB design.

Flow simulation data demonstrates:

• Direct airflow over the fuel injector during part-throttle operation.
• Significantly reduced turbulence around the injector area compared to traditional butterfly throttle bodies.
• Up to 20% less airflow restriction at full throttle when compared with conventional ITB systems.
• Improved airflow consistency across all cylinders for enhanced engine balance and performance.

The result is a highly efficient induction system capable of supporting both fast road and high-performance motorsport applications.

Premium Motorsport-Grade Construction

Every Rennen ITB by JSR system is manufactured to the highest standards using precision CNC machining and premium materials.

Precision CNC Machined

All components are machined from high-grade 6082-T6 aluminium to ensure exceptional dimensional accuracy and durability.

Perfect Airflow Distribution

Tight manufacturing tolerances ensure evenly distributed airflow across all throttle bodies, promoting balanced cylinder performance and simplified engine tuning.

Easy Synchronisation

The robust design incorporates minimal joints and connections, allowing straightforward throttle synchronisation and reducing the need for ongoing adjustment.

Long-Term Reliability

Throttle barrels are mounted within sealed ball bearings for smooth operation, durability and long service life under demanding conditions.

Premium Sealing Technology

All sealing surfaces utilise Viton O-rings to prevent false air entry and maintain optimal engine performance.

Quality Components Throughout

Only premium bearings, rod ends and stainless-steel fasteners are used throughout the assembly, ensuring reliability and durability in both road and track environments.

Hard Anodised Finish - Available in Gun Metal or Black Finish

All aluminium components receive a hard anodised gunmetal grey finish, providing corrosion resistance and an attractive motorsport inspired appearance.

Specification
Fuel Rails machined for EV6 injector type
3 bolt inlet manifold to cylinder head mounting
48mm velocity stack ID
120mm velocity stack length

The Ultimate Porsche Individual Throttle Body Upgrade

For enthusiasts seeking the ultimate air-cooled Porsche induction system, Rennen ITBs by JSR combine cutting-edge engineering, advanced airflow technology and premium construction quality. The innovative roller barrel design delivers exceptional throttle response, improved airflow efficiency, enhanced fuel atomisation and proven performance gains.

Rennen ITBs for Air-Cooled Porsche 964 - Advanced Roller Barrel Individual Throttle Bodies 

The Rennen ITBs by JSR represent the next generation of individual throttle body technology for air-cooled Porsche 964 engines. Designed and engineered specifically to extract optimal performance from classic Porsche flat-six engines, these innovative roller barrel throttle bodies deliver exceptional airflow, sharper throttle response, and improved engine efficiency compared to conventional butterfly valve throttle body systems.

Fits:

• Porsche 964 (911) C2 1989-93
• Porsche 964 (911) C4 1989-93
• Porsche 964 (911) RS 3.6L 1991-93
• Porsche 964 (911) RS 3.8L 1991-93

Developed through extensive research, flow simulation analysis and real-world testing, the Rennen ITB system provides a premium induction solution for performance-focused Porsche enthusiasts, restorers, track-day drivers and motorsport applications.

Whether you are building a high-performance Porsche 911 engine or converting a classic air-cooled Porsche to modern EFI, Rennen ITBs by JSR offer a significant advancement in intake technology.

Why Choose Rennen Roller Barrel ITBs?

Unlike traditional individual throttle bodies that utilise a butterfly valve positioned directly in the airflow path, the Rennen ITB system features a precision-engineered tapered roller barrel design.

This innovative approach provides several key advantages:

Unrestricted Airflow

The roller barrel design eliminates the butterfly valve obstruction found in conventional throttle bodies. With no throttle plate disrupting airflow, air moves more efficiently into the engine, improving volumetric efficiency and overall performance.

Increased Air Velocity

Because there is no butterfly valve occupying space within the throttle bore, the throttle body diameter can be optimised to maintain higher air velocity. Higher intake air speed promotes superior cylinder filling and enhanced engine response throughout the rev range.

Superior Fuel Atomisation

At partial throttle openings, airflow passes directly over the fuel injector. This promotes exceptional atomisation of the air-fuel mixture, improving combustion efficiency, drivability and throttle progression.

Instant Throttle Response

The short distance between the roller barrel and the inlet valve creates a highly responsive induction system, delivering immediate engine response and a direct connection between driver input and engine output.

The ITB kit comes with the ITBs mounted on intake manifolds and with fuel rails made for the EV6 injector type. 

Advanced Flow Simulation & Development

Extensive computational fluid dynamics (CFD) analysis and development testing have been carried out to optimise every aspect of the Rennen ITB design.

Flow simulation data demonstrates:

• Direct airflow over the fuel injector during part-throttle operation.
• Significantly reduced turbulence around the injector area compared to traditional butterfly throttle bodies.
• Up to 20% less airflow restriction at full throttle when compared with conventional ITB systems.
• Improved airflow consistency across all cylinders for enhanced engine balance and performance.

The result is a highly efficient induction system capable of supporting both fast road and high-performance motorsport applications.

Premium Motorsport-Grade Construction

Every Rennen ITB by JSR system is manufactured to the highest standards using precision CNC machining and premium materials.

Precision CNC Machined

All components are machined from high-grade 6082-T6 aluminium to ensure exceptional dimensional accuracy and durability.

Perfect Airflow Distribution

Tight manufacturing tolerances ensure evenly distributed airflow across all throttle bodies, promoting balanced cylinder performance and simplified engine tuning.

Easy Synchronisation

The robust design incorporates minimal joints and connections, allowing straightforward throttle synchronisation and reducing the need for ongoing adjustment.

Long-Term Reliability

Throttle barrels are mounted within sealed ball bearings for smooth operation, durability and long service life under demanding conditions.

Premium Sealing Technology

All sealing surfaces utilise Viton O-rings to prevent false air entry and maintain optimal engine performance.

Quality Components Throughout

Only premium bearings, rod ends and stainless-steel fasteners are used throughout the assembly, ensuring reliability and durability in both road and track environments.

Hard Anodised Finish - Available in Gun Metal or Black Finish

All aluminium components receive a hard anodised gunmetal grey finish, providing corrosion resistance and an attractive motorsport inspired appearance.

Specification
Fuel Rails machined for EV6 injector type
3 bolt inlet manifold to cylinder head mounting
50mm velocity stack ID
120mm velocity stack length

The Ultimate Porsche Individual Throttle Body Upgrade

For enthusiasts seeking the ultimate air-cooled Porsche induction system, Rennen ITBs by JSR combine cutting-edge engineering, advanced airflow technology and premium construction quality. The innovative roller barrel design delivers exceptional throttle response, improved airflow efficiency, enhanced fuel atomisation and proven performance gains.

Individual Throttle Bodies (ITB) Upgrade with ITG Normal Air Filter Set

Transform the character, responsiveness and visual appeal of your air-cooled Porsche with the Rennen by JSR Individual Roller Barrel Throttle Bodies (ITB) Upgrade for the Porsche 964 3.6ltr engine. Finished in a striking gunmetal coating and supplied with silver velocity stacks, ITG foam air filters, fuel rails machined for EV6 injectors and a precision-engineered mechanical throttle linkage system, this package delivers a perfect blend of motorsport-inspired performance and timeless Porsche styling.

Fits:

• Porsche 964 (911) C2 1989-93
• Porsche 964 (911) C4 1989-93
• Porsche 964 (911) RS 3.6L 1991-93
• Porsche 964 (911) RS 3.8L 1991-93

Unlike conventional butterfly throttle body systems, Roller Barrel Throttle Bodies utilise a rotating barrel mechanism that provides an unobstructed airflow path at wide-open throttle. This design has its roots in top-level motorsport and is widely regarded as one of the most responsive and visually impressive induction systems available for naturally aspirated engines.

For Porsche enthusiasts seeking the ultimate driving experience, the Rennen by JSR Roller Barrel ITB system offers a combination of performance, sound and aesthetics that transforms the character of the Porsche 964 3.6ltr

What Makes Roller Barrel Throttle Bodies Special?

Traditional throttle bodies use butterfly plates that partially obstruct airflow even when fully open. Roller Barrel Throttle Bodies utilise a cylindrical rotating barrel that creates a straighter and less restrictive airflow path.

The result is:

• Exceptional throttle response
• Improved airflow efficiency
• Reduced airflow turbulence
• Enhanced engine breathing
• Increased performance potential
• Smoother airflow characteristics
• Motorsport-inspired induction technology

Roller barrel systems are renowned for delivering an incredibly direct connection between throttle input and engine response.

Why Upgrade to Individual Roller Barrel Throttle Bodies?

The Porsche 964's air-cooled flat-six engine responds exceptionally well to individual throttle body induction systems.

With each cylinder receiving its own dedicated airflow source, engine responsiveness is transformed.

Benefits include:

• Instant throttle response
• Sharper acceleration feel
• Improved airflow distribution
• Increased induction efficiency
• Enhanced engine character
• Greater tuning flexibility
• Improved driver engagement
• Distinctive motorsport induction sound

The combination of Roller Barrel technology and individual throttle bodies creates one of the most desirable induction upgrades available for the Porsche 964 platform.

Motorsport Styling with Premium Engineering

The Rennen by JSR Roller Barrel ITB package is designed to look as impressive as it performs.

Featuring:

• Premium gunmetal-finished throttle bodies
• Silver velocity stacks
• ITG filters - Rennen normal version
• Precision mechanical throttle linkage

The result is a visually stunning engine bay that captures the appearance of classic Porsche race engines while incorporating modern engineering and manufacturing standards.

Mechanical Throttle Linkage for Maximum Driver Engagement

Included with the system is a precision-engineered mechanical throttle linkage assembly.

Unlike electronic (drive by wire) throttle systems, the mechanical linkage provides:

• Direct throttle actuation
• Exceptional pedal feel
• Immediate engine response
• Accurate throttle modulation
• Pure analogue driving feedback
• Motorsport-inspired control

This direct mechanical connection is a key element of the driving experience and one of the reasons enthusiasts favour traditional ITB systems.

Individual Throttle Bodies (ITB) Upgrade - 3 Stud Inlet Manifold

Transform the character, responsiveness and visual appeal of your air-cooled Porsche with the Rennen by JSR Individual Roller Barelle Throttle Bodies (ITB) Upgrade for the Porsche 964 3.6ltr engine. Finished in a striking gunmetal coating and supplied with silver velocity stacks, classic mesh air filters, fuel rails machined for EV6 injectors and a precision-engineered mechanical throttle linkage system, this package delivers a perfect blend of motorsport-inspired performance and timeless Porsche styling.

Fits:

• Porsche 964 (911) C2 1989-93
• Porsche 964 (911) C4 1989-93
• Porsche 964 (911) RS 3.6L 1991-93
• Porsche 964 (911) RS 3.8L 1991-93

Unlike conventional butterfly throttle body systems, Roller Barrel Throttle Bodies utilise a rotating barrel mechanism that provides an unobstructed airflow path at wide-open throttle. This design has its roots in top-level motorsport and is widely regarded as one of the most responsive and visually impressive induction systems available for naturally aspirated engines.

For Porsche enthusiasts seeking the ultimate driving experience, the Rennen by JSR Roller Barrel ITB system offers a combination of performance, sound and aesthetics that transforms the character of the Porsche 964 3.6ltr

What Makes Roller Barrel Throttle Bodies Special?

Traditional throttle bodies use butterfly plates that partially obstruct airflow even when fully open. Roller Barrel Throttle Bodies utilise a cylindrical rotating barrel that creates a straighter and less restrictive airflow path.

The result is:

• Exceptional throttle response
• Improved airflow efficiency
• Reduced airflow turbulence
• Enhanced engine breathing
• Increased performance potential
• Smoother airflow characteristics
• Motorsport-inspired induction technology

Roller barrel systems are renowned for delivering an incredibly direct connection between throttle input and engine response.

Why Upgrade to Individual Roller Barrel Throttle Bodies?

The Porsche 964's air-cooled flat-six engine responds exceptionally well to individual throttle body induction systems.

With each cylinder receiving its own dedicated airflow source, engine responsiveness is transformed.

Benefits include:

• Instant throttle response
• Sharper acceleration feel
• Improved airflow distribution
• Increased induction efficiency
• Enhanced engine character
• Greater tuning flexibility
• Improved driver engagement
• Distinctive motorsport induction sound

The combination of Roller Barrel technology and individual throttle bodies creates one of the most desirable induction upgrades available for the Porsche 964 platform.

Motorsport Styling with Premium Engineering

The Rennen by JSR Roller Barrel ITB package is designed to look as impressive as it performs.

Featuring:

• Premium gunmetal-finished throttle bodies
• Silver velocity stacks
• Classic mesh air filters
• Precision mechanical throttle linkage

The result is a visually stunning engine bay that captures the appearance of classic Porsche race engines while incorporating modern engineering and manufacturing standards.

Mechanical Throttle Linkage for Maximum Driver Engagement

Included with the system is a precision-engineered mechanical throttle linkage assembly.

Unlike electronic (drive by wire) throttle systems, the mechanical linkage provides:

• Direct throttle actuation
• Exceptional pedal feel
• Immediate engine response
• Accurate throttle modulation
• Pure analogue driving feedback
• Motorsport-inspired control

This direct mechanical connection is a key element of the driving experience and one of the reasons enthusiasts favour traditional ITB systems.

Rennen by JSR Individual Throttle Bodies (ITB) Upgrade for Modified Porsche 964 4.0ltr Engine

Developed for serious air-cooled Porsche performance builds, the Rennen by JSR Individual Throttle Bodies (ITB) Upgrade Kit for the Porsche 964 4.0ltr engine delivers exceptional airflow, lightning-fast throttle response and a true motorsport-inspired driving experience. Specifically configured for modified 4.0ltr engines featuring 45mm inlet bores and 50mm internal diameter Velocity Stacks, this induction package has been engineered to support the increased airflow demands of high-output naturally aspirated engine builds.

Fits:

• Porsche 964 (911) C2 1989-93
• Porsche 964 (911) C4 1989-93
• Porsche 964 (911) RS 3.6L 1991-93
• Porsche 964 (911) RS 3.8L 1991-93

This premium specification combines Gun Metal Individual Throttle Bodies, 50mm Silver Velocity Stacks, the Rennen Classic Mesh and Foam Air Filter Set and a Mechanical Throttle Linkage System, creating one of the most capable and visually impressive induction systems available for the Porsche 964 platform.

Whether fitted to a fast-road build, high-end restomod, track-focused machine or bespoke engine project, this system transforms the character of the Porsche flat-six while maximising its performance potential.

Designed for Modified 4.0ltr Engines

This ITB system has been developed specifically for enlarged-capacity Porsche 964 engines built to 4.0ltr and featuring 45mm inlet bores.

The larger bore specification provides:

• Increased airflow capacity
• Improved cylinder filling
• Enhanced high-RPM breathing
• Greater power potential
• Improved volumetric efficiency
• Enhanced throttle response
• Optimised compatibility with performance cylinder heads and camshafts

Combined with the 50mm velocity stack configuration, the system supports the airflow requirements of serious performance engine builds.

Why Upgrade to Individual Throttle Bodies?

Unlike a conventional plenum intake system, Individual Throttle Bodies provide each cylinder with its own dedicated throttle opening.

Benefits include:

• Instant throttle response
• Reduced intake restriction
• Improved airflow distribution
• Enhanced engine breathing
• Sharper acceleration
• Increased power potential
• Greater tuning flexibility
• Motorsport-inspired driving experience

The result is an engine that feels more responsive, more aggressive and more connected to driver inputs throughout the rev range.

Gun Metal Throttle Bodies

The Gun Metal finish provides a sophisticated motorsport appearance while showcasing the engineering quality of the induction system.

Benefits include:

• Premium finish
• Durable construction
• Distinctive engine bay appearance
• Complements air-cooled
• Porsche aesthetics
• Motorsport-inspired styling

50mm Silver Velocity Stacks

The oversized 50mm Velocity Stacks are specifically selected to complement the airflow requirements of the modified 4.0ltr engine.

Benefits include:

• Increased airflow capacity
• Reduced intake restriction
• Enhanced cylinder filling
• Improved throttle response
• Optimised high-performance breathing
• Classic Porsche race-engine appearance

These larger stacks are ideally suited to engines built for maximum naturally aspirated performance.

Classic Mesh & Foam Air Filters

This package includes the Rennen ITG Classic Mesh & Foam Air Filter Set, designed specifically to fit directly onto the 50mm Velocity Stacks.

Benefits include:

• Classic motorsport appearance
• Direct fitment to Rennen Velocity Stacks
• Excellent airflow characteristics
• Effective filtration against dust and debris
• Lightweight construction
• Washable and reusable foam elements
• Enhanced engine bay aesthetics
• Suitable for road and performance applications

The exposed mesh design perfectly complements the period-inspired appearance of the air-cooled flat-six while providing essential engine protection.

Mechanical Throttle Linkage

This kit includes the traditional mechanical throttle linkage system preferred by many Porsche enthusiasts.

Benefits include:

• Direct throttle feel
• Immediate driver feedback
• Proven reliability
• Authentic air-cooled character
• Motorsport-style operation

The mechanical linkage enhances the tactile and engaging nature of the ITB driving experience.

Why Choose the Rennen by JSR ITB System?

The Rennen by JSR system has been developed specifically for Porsche performance applications and engineered to maximise the potential of naturally aspirated air-cooled engines.

Benefits include:

• Exceptional throttle response
• Increased airflow capacity
• Improved engine breathing
• Enhanced induction acoustics
• Greater power potential
• Porsche-specific engineering
• Premium component quality
• Stunning engine bay presentation

It represents one of the most desirable induction upgrades available for a modified Porsche 964.

Rennen by JSR Individual Throttle Bodies (ITB) Upgrade for Modified Porsche 964 4.0ltr Engine

Developed for serious air-cooled Porsche performance builds, the Rennen by JSR Individual Throttle Bodies (ITB) Upgrade Kit for the Porsche 964 4.0ltr engine delivers exceptional airflow, lightning-fast throttle response and a true motorsport-inspired driving experience. Specifically configured for modified 4.0ltr engines featuring 45mm inlet bores and 50mm internal diameter Velocity Stacks, this induction package has been engineered to support the increased airflow demands of high-output naturally aspirated engine builds.

Fits:

• Porsche 964 (911) C2 1989-93
• Porsche 964 (911) C4 1989-93
• Porsche 964 (911) RS 3.6L 1991-93
• Porsche 964 (911) RS 3.8L 1991-93

This premium specification combines Gun Metal Individual Throttle Bodies, 50mm Silver Velocity Stacks, the Rennen ITG Air Filter Assembly (Normal Specification) and a Mechanical Throttle Linkage System, creating one of the most capable and visually impressive induction systems available for the Porsche 964 platform.

Whether fitted to a fast-road build, high-end restomod, track-focused machine or bespoke engine project, this system transforms the character of the Porsche flat-six while maximising its performance potential.

Designed for Modified 4.0ltr Engines

This ITB system has been developed specifically for enlarged-capacity Porsche 964 engines built to 4.0ltr and featuring 45mm inlet bores.

The larger bore specification provides:

• Increased airflow capacity
• Improved cylinder filling
• Enhanced high-RPM breathing
• Greater power potential
• Improved volumetric efficiency
• Enhanced throttle response
• Optimised compatibility with performance cylinder heads and camshafts

Combined with the 50mm velocity stack configuration, the system supports the airflow requirements of serious performance engine builds.

Why Upgrade to Individual Throttle Bodies?

Unlike a conventional plenum intake system, Individual Throttle Bodies provide each cylinder with its own dedicated throttle opening.

Benefits include:

• Instant throttle response
• Reduced intake restriction
• Improved airflow distribution
• Enhanced engine breathing
• Sharper acceleration
• Increased power potential
• Greater tuning flexibility
• Motorsport-inspired driving experience

The result is an engine that feels more responsive, more aggressive and more connected to driver inputs throughout the rev range.

Gun Metal Throttle Bodies

The Gun Metal finish provides a sophisticated motorsport appearance while showcasing the engineering quality of the induction system.

Benefits include:

• Premium finish
• Durable construction
• Distinctive engine bay appearance
• Complements air-cooled
• Porsche aesthetics
• Motorsport-inspired styling

50mm Silver Velocity Stacks

The oversized 50mm Velocity Stacks are specifically selected to complement the airflow requirements of the modified 4.0ltr engine.

Benefits include:

• Increased airflow capacity
• Reduced intake restriction
• Enhanced cylinder filling
• Improved throttle response
• Optimised high-performance breathing
• Classic Porsche race-engine appearance

These larger stacks are ideally suited to engines built for maximum naturally aspirated performance.

ITG Air Filter Assembly (Normal Specification)

The included ITG Air Filter Assembly provides effective filtration without compromising airflow.

Benefits include:

• Protects engine internals
• Maintains high airflow efficiency
• Washable and reusable filter media
• Supports engine longevity
• Suitable for road and fast-road applications

The normal specification assembly provides an ideal balance between filtration, airflow and practicality.

Mechanical Throttle Linkage

This kit includes the traditional mechanical throttle linkage system preferred by many Porsche enthusiasts.

Benefits include:

• Direct throttle feel
• Immediate driver feedback
• Proven reliability
• Authentic air-cooled character
• Motorsport-style operation

The mechanical linkage enhances the tactile and engaging nature of the ITB driving experience.

Why Choose the Rennen by JSR ITB System?

The Rennen by JSR system has been developed specifically for Porsche performance applications and engineered to maximise the potential of naturally aspirated air-cooled engines.

Benefits include:

• Exceptional throttle response
• Increased airflow capacity
• Improved engine breathing
• Enhanced induction acoustics
• Greater power potential
• Porsche-specific engineering
• Premium component quality
• Stunning engine bay presentation

It represents one of the most desirable induction upgrades available for a modified Porsche 964.

Mechanical Throttle Linkage Assembly for Individual Throttle Body (ITB) Systems

The Rennen Mechanical Throttle Linkage Assembly is a precision-engineered solution designed specifically for Rennen Individual Throttle Body (ITB) conversions. Available in two configurations, one for the traditional solid accelerator rod system found in classic Porsche 911 models and another for the accelerator cable system used on Porsche 964 models, this assembly provides smooth, accurate and reliable throttle operation.

Fits:

• Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
• Porsche 911 1978-1983 3.0L / SC
• Porsche 911 1984-1986 3.2L
• Porsche 911 1987-1989 3.2L G50
• Porsche 964 (911) C2 1989-93
• Porsche 964 (911) C4 1989-93
• Porsche 964 (911) RS 3.6L 1991-93
• Porsche 964 (911) RS 3.8L 1991-93

As one of the most critical components in an ITB installation, the throttle linkage transfers driver input directly to the throttle bodies, ensuring precise synchronisation and immediate engine response. Designed to integrate seamlessly with Rennen by JSR ITB systems, the linkage assembly delivers the direct mechanical feel Porsche enthusiasts expect while maintaining excellent throttle control and drivability.

Whether you're building a high-performance road car, a track-focused machine or a fully restored air-cooled Porsche, a properly engineered throttle linkage is essential for unlocking the full potential of an ITB conversion.

What Does a Mechanical Throttle Linkage Do?

The throttle linkage connects the accelerator pedal mechanism to the individual throttle bodies, translating driver input into precise throttle movement.

Its primary functions include:

• Controlling throttle opening and closing
• Synchronising multiple throttle bodies
• Delivering accurate throttle response
• Providing smooth pedal feel
• Maintaining consistent throttle operation
• Supporting reliable engine performance

The assembly is available in two versions:

Porsche 911 Solid Accelerator Rod Version

Designed for classic Porsche 911 models that utilise the factory mechanical rod linkage system. This version integrates with the original accelerator rod arrangement while providing accurate control of the ITB system.

Porsche 964 Accelerator Cable Version

Designed for Porsche 964 models equipped with a throttle cable system. This version provides a clean and reliable connection between the accelerator cable and the individual throttle body assembly.

Why Is an ITB Upgrade So Appealing?

Individual Throttle Body systems are widely considered one of the most rewarding naturally aspirated performance upgrades available for Porsche engines.

Unlike conventional intake systems that use a shared plenum, ITBs provide each cylinder with its own dedicated throttle body, allowing the engine to breathe more efficiently and respond instantly to throttle inputs.

Benefits of a Rennen by JSR ITB conversion include:

• Immediate throttle response
• Improved airflow efficiency
• Enhanced engine breathing
• Increased performance potential
• Greater tuning flexibility
• Distinctive induction sound
• Improved driver engagement
• Motorsport-inspired driving characteristics

For many Porsche enthusiasts, the combination of razor-sharp throttle response and an unmistakable induction note makes ITBs one of the most desirable engine upgrades available.

Why a Quality Throttle Linkage Matters

Even the best throttle bodies cannot perform correctly without a precise and reliable linkage system.

A high-quality linkage assembly helps:

• Deliver accurate throttle control
• Maintain throttle body synchronisation
• Improve pedal feel
• Eliminate unwanted play or movement
• Support consistent engine tuning
• Improve overall drivability
• Maximise ITB performance benefits

A properly engineered linkage transforms the driving experience by creating a direct connection between the driver and the engine.