Raggdoll Motorsports Equal-Length, Equal-Velocity Exhaust Manifold for Porsche 718 (982) Cayman/Boxster (2.5L Turbo and High Power 2.0L)

Overview of Raggdoll Motorsports Equal Length Equal velocity Manifold. 
The Porsche 718 (982) Cayman and Boxster models equipped with the 2.5L and high power 2.0L turbocharged flat-four engines deliver impressive performance, but their factory log-style exhaust manifold presents significant limitations—particularly for modified and tuned cars.

The stock manifold was designed primarily for emissions compliance and cost-effective manufacturing, rather than optimized flow dynamics. The unequal exhaust valve lift that these motors have from cylinder to cylinder further complicates exhaust flow, creating an imbalance in velocity and backpressure. This is also what causes the 718 to sound much like a Subaru, that many don’t care for. Rather than a well balanced sounding Porsche boxer motor. 

More critically, cylinders #1 and #3 expel exhaust directly into the manifold wall, causing severe flow disruption, excessive backpressure, and long-term reliability issues. Over time, this results in bearing wear, excessive leak-down in those two cylinders, and even head-lifting under high boost conditions.

To eliminate these weaknesses, Raggdoll Motorsports has developed the first true equal-length, equal-velocity exhaust manifold for the Cayman Boxster 718 that corrects the factory design flaws, optimizes turbo efficiency, sound, and enhances engine reliability. Along with making the 718 sound closer to a GT car than a Subaru Outback. 

⸻

The Cayman Boxster 718 Stock Log Turbo Manifold Issues and Their Long-Term Impact on our motors. 

1. Excessive Back-pressure in Cylinders #1 & #3 

• The lower exhaust valve cylinders #1 & #3 naturally reduces their flow potential.
• In the stock log manifold, these cylinders’ exhaust gases slam directly into a flat manifold wall, creating severe turbulence, pressure spikes, and reversion (exhaust gases pushing back into the combustion chamber).
• This leads to inefficient scavenging, trapping residual exhaust gases in those cylinders and reducing combustion efficiency.

2. Uneven Load on Bearings & Premature Engine Wear

• Because cylinders #1 & #3 experience higher exhaust resistance, they have to work harder to expel gases.
• This uneven resistance increases crankshaft loading, leading to premature bearing wear and excessive leak-down in those cylinders over time.
• Tuned and un-tuned 718s we are seeing our motors suffer from early wear and engine range due to this imbalance.

3. Increased Risk of Head Lifting in High-Boost Applications 

• Unequal back-pressure cause uneven cylinder pressures, which can distort head clamping forces.
• Under high boost, cylinders #1 and #3 see excessive pressure buildup, increasing the risk of head lifting or head gasket failure.

4. Reduced Turbo Efficiency & Response

• Because the stock manifold does not evenly distribute exhaust pulse energy, it delivers inconsistent pulses to the turbo, causing boost lag and inefficient turbine performance.
• Uneven pulse strength can also create unstable boost pressure at higher RPMs.These flow and pressure issues become significantly worse when modifying the engine for higher boost and power, making the stock manifold an active limiting factor for performance and reliability.

⸻

How My Raggdoll Equal-Length, Equal-Velocity Manifold Solves These Issues

1. Equal-Length Primary Runners for Uniform Pulse Timing

✅ Each runner is engineered to be identical in length, ensuring exhaust pulses reach the turbo at evenly spaced intervals.

✅ This eliminates timing irregularities that cause inconsistent boost response and reduces stress on the turbine.

✅ Smooth mandrel-bent tubing replaces the restrictive cast log, minimizing pressure losses and maximizing velocity.

2. Velocity-Matched Exhaust Flow to Balance Cylinder Pressures.

✅ The primary tube diameters are carefully tuned to compensate for the different valve lifts that our 718’s have. 

✅ This ensures that all cylinders deliver exhaust pulses at similar speeds, preventing uneven backpressure buildup.

3. High-Efficiency 4-2-1 Merge Collector Design

✅ The system features a 4-2-1 configuration, using two 2-1 merge collectors before the final collector at the turbo flange.

✅ Key collector design elements:

• At the collectors a specific tuned angle° is used and total included merge angle for smooth pulse transition.
• Internal step up’s and down in specific locations in multiple area’s to equalize velocity.
• Designed to prevent crossflow turbulence and improve exhaust energy retention.

✅ Final ID collector outlet smoothly transitions into the turbo’s 2.5” inlet, maximizing pulse energy transfer.

4. Improved Exhaust Scavenging & Reduced Cylinder Stress

✅ Balanced pulse energy enhances scavenging, improving cylinder filling and combustion efficiency.

✅ Reducing the pressure spike on cylinders #1 and #3 eliminates their uneven crankshaft loading, helping to prolong bearing life.

✅ Smoother pressure distribution across all four cylinders reduces stress on the head gasket, lowering the risk of head lifting at high boost.

⸻

Performance Gains & Reliability Improvements along with improved sound. 

✅ Faster Turbo Spool & Response → Evenly distributed exhaust pulses improve turbine efficiency, reducing boost lag, seeing 500 to 700 rpm quicker spool up. 

✅ More Consistent Cylinder Pressures → Balanced scavenging prevents excessive residuals in cylinders #1 & #3.

✅ Increased Engine Longevity → Reduced bearing stress and back-pressure extend engine durability.

✅ Lower Risk of Head Lifting → Improved pressure distribution reduces head gasket failure risk.

✅ More Predictable Power Delivery → Even exhaust pulses create a smoother powerband and more stable boost control.

✅ Optimized for High-Performance Applications → Supports higher boost levels and track use without the reliability concerns of the stock manifold.

✅ All of this in the end makes 718 sound like the beautiful engineered track eating machine that it is  

⸻

Construction & Fitment

✔️ High-Quality Materials:

• stainless steel billet and 3d printed construction technology for extreme precision flow characteristics.
• TIG-welded with full back-purging for smooth internal flow.
• Ceramic-coated to improve heat retention and lower engine bay temperatures.

✔️ Precision-Engineered Fitment:

• Direct bolt-on replacement for 2017+ Porsche 718 Cayman & Boxster ( 2.5L and high power 2.0L).
• Compatible with both stock and aftermarket turbochargers.

⸻

Final Verdict: The Ultimate Turbo Manifold Upgrade for the Cayman Boxster 718 is the Raggdoll ELEV Manifold. 

The factory log manifold is a known weak point in the 718’s turbo system, not only limiting performance but also creating long-term engine reliability concerns—especially under high boost.

By switching to the Raggdoll Motorsports Raggdoll-engineered equal-length, equal-velocity manifold, you eliminate the uneven backpressure issues that cause poor sound, premature bearing wear, excessive leak-down, and head lifting. The balanced exhaust pulses enhance sound, turbo efficiency, improved scavenging, and reduce mechanical stress, delivering both higher performance and greater engine longevity.

Whether you’re looking to extract maximum power from a tuned 718 or future-proof your engine against wear and failure, the Raggdoll exhaust manifold is the single best upgrade for the platform.

✅ More Power

✅ Faster Turbo Response

✅ Smoother Power Delivery to redline

✅ Longer Engine Life

This is the definitive solution for 718 enthusiasts seeking both performance and durability—engineered for the road and track.

‍