*High-Flow Performance Turbocharger Built from a New BorgWarner Assembly

Porsche 718 Cayman & Boxster Rennen HF High-Flow Turbocharger – RaggDoll Motorsports

Maximum Flow. Relentless Power. Race-Level Engineering

The RaggDoll Rennen HF is a high-flow K04 hybrid turbocharger upgrade for the Porsche 718 Cayman and Boxster 2.0L Base and T (982 platform), engineered for fast spool, high efficiency, and 500+ crank horsepower capability with proper supporting modifications.

Developed as the next evolution of our proven Rennen turbo, the HF version incorporates extensive race-style housing porting and in-house aerodynamic revisions to significantly increase airflow, improve response, and extend usable power at higher RPM.

This is not a lightly modified turbo. The Rennen HF is designed for owners who want real performance gains, not inflated claims.

Why the Rennen HF Turbocharger Exists

Building on a platform that already outperforms typical K04 hybrid upgrades for the Porsche 718 2.0L, the Rennen HF pushes airflow and efficiency further with aggressive compressor and turbine housing optimization.

When paired with proper fueling and supporting modifications, the Rennen HF is capable of delivering 500+ crank horsepower on pump fuel, with:

• Faster boost response
• Stronger mid-range torque
• Improved top-end power that carries cleanly to redline

All while maintaining OEM-style drivability and reliability.

RaggDoll Rennen HF Features & Benefits

• ‍True Plug-and-Play Installation - Direct bolt-on replacement with no vehicle modifications required.‍
• Race-Ported Compressor & Turbine Housings - Extensive, hand-finished porting to reduce restriction, turbulence, and backpressure.‍
• Advanced High-Flow Compressor Design - Optimized for increased mass airflow and a broader, more usable powerband.‍
• High-Flow Turbine Wheel- Designed for fast spool without sacrificing top-end breathing.‍
• Genuine BorgWarner Cartridge - Built using OEM-quality internals and housings for long-term reliability
• ‍Inconel Turbine Wheel - Rated for sustained exhaust temperatures up to 1050°C (1922°F).‍
• Lower IATs Under Boost - Increased airflow efficiency allows more power at lower boost pressure.‍
• Track-Tested & Dyno-Validated - Developed through real-world testing, not theoretical simulations.‍
• In-House Aerodynamic Revisions - Internal flow refinements designed to improve response and mass flow without compromising durability.

What Housing Porting Does for Turbocharger Performance

Careful, race-style porting of the compressor and turbine housings improves turbocharger performance by:

• Reducing airflow restrictions throughout the housing passages
• Eliminating sharp transitions that cause turbulence and pressure loss
• Increasing air and exhaust gas velocity through the turbo
• Improving spool characteristics and overall efficiency
• Minimizing pressure drop for a more favorable pressure ratio

On the Rennen HF, the turbine inlet, volute passages, and compressor cover transitions are aggressively optimized to increase flow while preserving exhaust gas velocity—critical for both response and top-end power.‍

Designed for Real-World Performance

‍The RaggDoll Rennen HF turbo upgrade for the 718 Cayman and Boxster 2.0L Base and T platform was developed through extensive R&D across multiple vehicles, calibrations, fuels, and track environments.

Results include:

• Earlier, stronger boost onset
• Wider and more usable powerband
• Lower heat and reduced backpressure
• Consistent performance during extended track use
• OEM-like reliability with dramatically increased output

Proprietary Compressor & Turbine Pairing

- The Rennen HF uses a carefully matched compressor and turbine combination designed to work as a balanced system:

High-Flow Compressor Wheel

- Engineered to maximize airflow and efficiency while maintaining stable boost control and minimizing surge. This allows for increased power capability without sacrificing drivability.

Matched High-Flow Turbine Wheel

- Optimized to preserve exhaust energy and reduce drive pressure, improving response and maintaining efficiency at higher RPM.

Stealth Flow Enhancements

- Internal aerodynamic revisions that improve gas inertia and volumetric efficiency while maintaining blade integrity and long-term durability.

To unlock the full potential of the Rennen HF, pairing it with a high-flow turbo inlet and supporting airflow upgradesis strongly recommended.

Who This Turbo Is For

Ideal for Porsche 718 Cayman & Boxster 2.0L Base and T owners who are:

• Running ECU tuning or custom calibration
• Upgrading intake, intercooling, or fueling systems
• Seeking a higher power ceiling with reliable drivability
• Building a fast street car or dual-purpose street/track setup

This turbo is designed for owners who want real, repeatable performance gains — not short-lived dyno numbers.

Install & Tuning Notes

Professional installation is recommended. ECU tuning is required to safely and fully utilize the increased airflow capability.  Always consult your tuner prior to installation. 

What’s Included

• New Genuine OEM BorgWarner Rennen HF (HIGH FLOW) Turbocharger Assembly
• Laser-Etched RaggDoll Series Identification

The RaggDoll Turbocharger Process

All RaggDoll Series turbochargers are remanufactured to OEM specifications and tolerances, retaining the original center cartridge and housings unless a new BorgWarner unit is requested.

Each turbo undergoes:

• Complete disassembly, cleaning, and inspection
• Precision machining of housings based on the Rennen HF specification
• Independent dynamic balancing of turbine and compressor wheels
• Replacement of all bearings, seals, thrust components, and hardware
• Final high-speed VSR balancing as a complete cartridge assembly at up to 250,000 RPM

Each compressor housing is stripped, refinished, and laser-etched with RaggDoll Series identification to ensure traceability and authenticity.

Why Choose RaggDoll Motorsports

RaggDoll turbochargers are not mass-produced catalog parts. They are engineered solutions, developed through real testing and refined through experience on the Porsche 718 platform.

From the moment you unbox a RaggDoll turbo, the difference is obvious:

• Top-tier components
• Thoughtful engineering
• Track-tested, street-proven performance

Built differently — because performance demands it.