Roller Barrel ITB Upgrade Set for 3 Stud Manifold. Porsche 964 4.0ltr  ❭  ITB403BOLTCMFSET

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.