HKS Equal Length Exhaust Manifold

Part #: 14019-AF002

Overview

The HKS SUH409 Equal Length EJ25 Turbo Exhaust Manifold is a high-performance upgrade designed specifically for Subaru EJ25 engines, including models such as the Impreza WRX STI from 2008 to 2021. Crafted to replace the OEM header, this exhaust manifold features a 4-1 design that enhances exhaust flow, supporting improved spool and overall turbo response. It is ideal for enthusiasts seeking to maximize their vehicle’s performance potential, whether pushing the limits of the stock turbo or optimizing a custom setup. Constructed with precision and quality materials, this manifold helps improve low and high-range power delivery while maintaining OEM-level mid-range performance, making it a versatile upgrade for spirited driving or competitive applications.

Key Features

This exhaust manifold is engineered with a focus on durability and performance, featuring:

• High-quality stainless steel construction for corrosion resistance and longevity
• Equal length primary pipes to optimize exhaust scavenging and flow
• Precision-welded flanges for a secure, leak-free connection
• Optimized 4-1 collector design for improved spool and response
• Enhanced exhaust flow supporting better turbo efficiency and power output
• Designed to fit Subaru EJ25 engines, including various Impreza WRX STI models

Construction & Design

The HKS SUH409 features a meticulously crafted stainless steel construction, ensuring strength and resistance to high temperatures and corrosion. The equal length primary pipes are precisely fabricated to promote balanced exhaust flow, reducing backpressure and enhancing turbo spool characteristics. The flanges are machined for a perfect fit, ensuring a reliable seal and ease of installation. The overall design emphasizes durability and performance, making it a reliable upgrade for demanding driving conditions.

Driving Feel & Feedback

Installing this exhaust manifold results in a noticeable improvement in turbo response and spool time, providing a more immediate and responsive driving experience. The optimized flow characteristics contribute to smoother acceleration and a more aggressive exhaust note, enhancing the overall driving engagement without compromising reliability or daily drivability.

Installation & Fitment

Designed as a direct replacement for the OEM header on Subaru EJ25 engines, installation requires standard mechanical skills and basic tools. Proper fitment should be verified against vehicle specifications and the part number to ensure compatibility. The manifold is intended for performance upgrades and may require additional tuning or supporting modifications for optimal results.

What’s Included

The package includes the HKS Equal Length EJ25 Turbo Exhaust Manifold, ready for installation. Hardware and gaskets are not included and should be sourced separately to ensure a proper seal and fitment.