Turbo Manifold Honda K20/K24 RWD Large Primary
Honda K20/K24 RWD Large Primary Turbo Manifold
Developed specifically for high-power Honda K20 and K24 rear-wheel-drive conversions, the Walton Motorsport RWD Large Primary Turbo Manifold combines conversion-friendly turbo positioning with 42.56 mm ID primary runners for engine combinations requiring greater exhaust-flow capacity.
Designed for higher-output, high-revving and larger-displacement K-Series builds, this is the RWD manifold for applications where top-end flow and power potential take priority over the response characteristics of a smaller-primary manifold.
Large Primary – Built for Higher-Flow K-Series Builds
The defining feature of this manifold is its 42.56 mm internal-diameter primary runners.
The increased primary diameter provides additional exhaust-flow capacity for K20 and K24 combinations operating at higher engine speeds, increased displacement or greater power levels.
That makes the Large Primary particularly relevant to extensively developed K24 and high-output K20 combinations where the engine's airflow requirements justify stepping up from a smaller, response-focused runner.
Honda K Series Turbo Manifold - Developed for RWD K20 & K24 Conversions
This manifold is designed specifically around longitudinal K-Series installations, rather than the conventional transverse FWD K20/K24 layout.
Confirmed applications include:
- Nissan S-chassis K20/K24 conversions
- Toyota GT86 K20/K24 conversions
- Other RWD K-Series conversions where surrounding chassis clearance allows
This makes it a purpose-built option for drift, circuit, drag and high-performance street projects using the K-Series outside its traditional Honda chassis.
Honda K Series Turbo Manifold - Modern V-Band Turbo Options
The manifold is available with a Garrett V-Band turbo inlet suitable for G25, G30 and G35 turbochargers, as well as GTX30 and GTX35 applications.
Turbocharger selection should reflect the engine specification and intended use of the car. The larger-primary manifold is particularly suited to combinations where greater turbocharger airflow and top-end performance justify sacrificing some of the gas-speed advantage of a smaller runner.
Honda K Series Turbo Manifold - Wastegate & Boost Control
The manifold features a 40–50 mm external wastegate port, allowing the final wastegate configuration to be selected around the turbocharger, boost level and engine combination.
The wastegate port is supplied without a flange fitted, providing flexibility when specifying the final boost-control package.
Honda K Series Turbo Manifold - Conversion Fitment
Because this manifold is intended for engine conversions, the recipient chassis is an important part of selecting the correct manifold.
Confirmed fitment information:
- Nissan S-chassis – compatible
- Toyota GT86 – compatible
- Mazda MX-5 – not compatible due to the high chassis legs
Final clearance can also depend on engine position, engine mounts, steering components, turbocharger size and surrounding hardware, so custom conversion applications should be checked individually before ordering.
Is the Large Primary Right for Your Honda K-Series Build?
Choose the RWD Large Primary when building a higher-output K20/K24 combination where increased exhaust-flow capacity, high-RPM performance and top-end power are priorities.
For a lower-power or more response-focused K-Series combination, a smaller-primary manifold may provide a better match to the engine and intended use.
If you're unsure which K-Series manifold or turbocharger combination best suits your RWD conversion, contact Walton Motorsport before ordering and we can help specify the system around your chassis, engine and performance goals.
Further Questions?
Turbo Manifold Honda K20/K24 RWD Large Primary - Garrett V-Band (G25/G30/G35, GTX30/GTX35) / 40 - 50mm Port Size (NO flange fitted) is backordered and will ship as soon as it is back in stock.
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Turbo Manifold Honda K20/K24 RWD Large Primary
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Suits Engine
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Suits ChassisNissan S13, Nissan S14, Nissan S15, Toyota ZN6, Subaru ZC6
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Built to Last. Backed for Life.
A lifetime warranty is easy to offer. Building a turbo manifold that's unlikely to ever need it is the hard part.
You can find the full details of the Walton Motorsport Warranty HERE
Every Walton Motorsport manifold is engineered to withstand the extreme temperatures, vibration and abuse that come with high-performance street and race applications. From material selection and fabrication to our cast collectors and proven designs, durability is built into every product.
The biggest inconvenience of a failed manifold isn't the repair—it's the downtime, the labour to remove it, and the event or track day you might miss. That's why our focus has always been on preventing failures before they happen, not simply replacing parts after they do.
We're proud to stand behind every manifold we manufacture with a Lifetime Warranty. While no mechanical component is indestructible, our goal has always been simple: build products that earn your trust by performing reliably for years to come.
Because when you choose Walton Motorsport, the last thing you should be worrying about is your manifold.
Material Selection
Every Walton Motorsport manifold starts with carefully selected 304 stainless steel tubing. Not all 304 stainless is manufactured to the same standard, and the quality of the tubing plays a critical role in the durability of the finished product.
Turbo manifolds are subjected to thousands of extreme heat cycles throughout their life. Lower-quality tubing can fatigue over time, and we've seen inferior materials crack or split along the welded seam under these conditions. That's why we specify the exact tube grade and wall characteristics we know will perform reliably in demanding street and motorsport applications.
Our cylinder head flanges are designed in-house and precision cut using modern fibre laser technology, providing exceptional dimensional accuracy and repeatability. Compared to traditional CO₂ laser cutting, fibre laser cutting delivers cleaner edges and tighter tolerances, ensuring an accurate fit and consistent sealing.
Manufacturing Process
Port-Matched Flange Construction
Rather than simply welding the runners to the face of the flange, Walton Motorsport machines each runner to pass through the flange before it is TIG welded from both sides. The ports are then hand-finished to produce a smooth, uninterrupted transition from the cylinder head into the runner.
This manufacturing method delivers several important advantages:
- Increased weld strength and long-term durability.
- Improved gas flow by eliminating abrupt transitions.
- A smoother change from the oval exhaust port to the round runner.
- Reduced turbulence for improved exhaust efficiency.
The result is a manifold that is stronger, flows better, and is built to withstand years of hard use.
Cast Merge Collector
At the heart of every Walton Motorsport manifold is our proprietary cast merge collector, designed entirely in-house.
Our latest collector design delivers the highest wastegate flow we've achieved while maintaining excellent merge efficiency into the turbine. The internal geometry provides smooth gas transitions, minimising turbulence and helping to reduce exhaust gas temperatures without sacrificing performance.
Unlike fabricated collectors assembled from multiple sections, our one-piece cast design eliminates internal joints and welds within the collector itself. This not only optimises gas flow but also significantly improves structural integrity, reducing the likelihood of collector failures that can damage turbochargers or engines.
Every design decision is made with the same objective: maximum performance, exceptional durability, and complete confidence when pushing your engine to its limits.
For a deeper look at our engineering philosophy and manufacturing methods, visit our Technical Centre.
Proven Motorsport Experience
In every Walton Manifold
