Porsche 718 Cayman & Boxster Exhaust Manifold / Turbo Header – 2.0T & 2.5T S / GTS (2017–2025)‍

Equal-Length, Equal-Velocity (ELEV) Turbo Exhaust Manifold

Engineered for Performance, Reliability, and Sound

The Porsche 718 Cayman and Boxster exhaust manifold used on the factory 2.0T and 2.5T turbocharged flat-four engines is one of the most overlooked mechanical limitations of our platform. While adequate for emissions compliance and packaging, the OEM log-style manifold compromises exhaust flow, pulse timing, turbo efficiency, sound quality, and—most critically—long-term engine reliability once boost, tuning, or sustained load is introduced.

The RaggDoll Motorsports Equal-Length, Equal-Velocity (ELEV) Exhaust Manifold was engineered to correct these factory flaws at their source by restoring balanced exhaust flow, uniform pulse timing, and equalized cylinder pressure across all four cylinders.

This is not a cosmetic header or a simple tubular replacement. It is a complete re-engineering of how exhaust energy is delivered to the turbocharger on the Porsche 718 platform.

The Fundamental Problem with the Stock 718 Turbo Manifold

Unequal Exhaust Valve Lift & Poor Flow Geometry

The Porsche 718 platform uses unequal exhaust valve lift, with cylinders #1 and #3 flowing less than cylinders #2 and #4. In the factory log manifold, this imbalance is significantly amplified by poor internal geometry.

Rather than flowing smoothly into a collector, exhaust gases from cylinders #1 and #3 impact a flat internal wall before turning toward the turbine. This creates:

• Severe internal turbulence
• Localized pressure spikes
• Exhaust reversion into the cylinder
• Excessive back-pressure

This imbalance is also responsible for the uneven, raspy, “Subaru-like” exhaust tone many owners dislike—rather than the clean, balanced sound expected from a Porsche boxer engine.

Long-Term Engine Consequences of the Factory Manifold

Excessive Back-Pressure in Cylinders #1 & #3

• Lower-lift exhaust valves already reduce flow potential
• Log-style geometry compounds restriction
• Exhaust reversion contaminates the combustion process
• Reduced scavenging and combustion efficiency
  

Uneven Bearing Load & Premature Wear

• Cylinders #1 & #3 must work harder to expel exhaust gases
• Uneven crankshaft loading accelerates bearing wear
• Increased leak-down is commonly observed over time
• Occurs on both tuned and completely stock engines
  

Increased Risk of Head Lifting Under Boost

• Uneven exhaust back-pressure creates uneven cylinder pressure
• Distorted head clamping forces at higher boost levels
• Raises the risk of head lift and head gasket failure
  

Reduced Turbo Efficiency & Inconsistent Boost

• Uneven pulse energy delivered to the turbine
• Slower spool and unstable boost at higher RPM
• Becomes exponentially worse as airflow and power increase
  

At higher boost and sustained load, the factory exhaust manifold becomes an active reliability liability, not merely a performance bottleneck.

How the RaggDoll ELEV Exhaust Manifold Fixes Every Issue

RaggDoll Motorsports engineered the first true equal-length, equal-velocity exhaust manifold specifically for the Porsche 718 platform—designed around the engine’s real mechanical constraints, not generic header theory.

Equal-Length Primary Runners

• Near Identical runner lengths ensure uniform pulse timing
• Evenly spaced exhaust pulses at the turbine
• Faster, more stable turbo spool
• Mandrel-bent tubing replaces restrictive cast geometry
  

Velocity-Matched Flow for Unequal Valve Lift

• Primary diameters are tuned to compensate for unequal exhaust valve lift
• Cylinders #1 & #3 receive velocity correction, not restriction
• All four cylinders deliver exhaust energy at similar velocity
• Eliminates localized back-pressure buildup
  

High-Efficiency CNC Merge Collector System

• Dual 2-into-1 merge collectors feeding the final turbo collector
• Tuned merge angles for smooth pulse convergence
• Strategic internal step-ups and step-downs to equalize velocity
• Prevents cross-flow turbulence and pulse collision
• Smooth transition into the turbo’s 2.5” inlet for maximum energy transfer
  

Performance, Reliability & Sound Improvements

• Faster turbo spool (In most set-ups)
• More consistent cylinder pressures across all four cylinders
• Improved exhaust scavenging and combustion efficiency
• Reduced bearing stress and crankshaft loading
• Lower risk of head lifting under high boost
• Smoother, more predictable power delivery to redline
• Supports higher boost and sustained track use
• Transforms the exhaust note from that uneven boxer rumble or worbaly sound to a clean, GT-like, flat plane 4 cylinder exotic balanced tone

Construction & Fitment

Premium Materials & Manufacturing

• Stainless steel construction
• Billet flow-optimized flanges and collectors 
• TIG-welded with full back-purging
• Ceramic-coated for heat retention and reduced engine bay temperatures
  

Precision Fitment

• Direct bolt-on replacement
• Fits all 2017–2025 Porsche 718 Cayman & Boxster‍
• Compatible with 2.0T and 2.5T engines
• Works with stock and aftermarket turbochargers
  

Final Verdict: The Definitive 718 Turbo Exhaust Manifold Upgrade‍

The factory Porsche 718 exhaust manifold is one of the most critical weak points in the turbo system—limiting performance, degrading sound quality, and accelerating long-term engine wear.

The RaggDoll Equal-Length, Equal-Velocity Exhaust Manifold eliminates these flaws entirely by restoring balanced exhaust flow, proper pulse timing, and equalized cylinder pressure.

More power. Faster response. Smoother delivery. Longer engine life.

If you are serious about performance and reliability, this is the single most important exhaust upgrade you can make for the Porsche 718 platform—engineered for both street and track.

Why Choose RaggDoll Motorsports

RaggDoll Motorsports parts are engineered solutions—not mass-produced catalog components. The ELEV Exhaust Manifold was built to fix the factory system at its source, prioritizing balanced flow, turbo efficiency, and long-term engine reliability—not marketing hype.

Precision engineering. Proven results.
Built for drivers who demand performance without compromise.