Tsm Race K-series 4-1 Header W/ Megaphone & 3” Vband

TSM Race 4-1 K-Series Header with Megaphone & 3" V-Band

The TSM Race 4-1 K-Series Header is a performance-focused exhaust upgrade designed for Honda K-Series engines. Its purpose is to improve exhaust gas evacuation, reduce exhaust restriction, and help the engine produce more horsepower and torque, particularly in the mid-to-high RPM range.

This header is especially appealing for naturally aspirated K-Series builds where maximizing airflow and top-end performance is a priority.

Key features and performance benefits

1. 4-1 Performance Header Design

The four individual exhaust runners merge into one collector, creating a more direct exhaust path. Compared with a typical factory exhaust manifold, a properly designed 4-1 header can offer:

Improved exhaust scavenging at higher RPM

Reduced exhaust backpressure

Better high-RPM horsepower potential

Improved throttle response when properly matched to the engine

2. Megaphone Collector

The megaphone-style outlet is designed to influence exhaust gas velocity and pressure-wave behavior.

Potential benefits include improved exhaust pulse tuning, better high-RPM breathing, and stronger top-end power when matched with the appropriate engine setup.

3. 3-Inch V-Band Connection

The 3-inch V-band outlet is particularly useful for performance exhaust systems.

It provides a secure connection, makes exhaust removal easier, and supports integration with a properly sized 3-inch exhaust system.

4. Performance-Oriented Construction

The pictured header features polished metal tubing, welded joints, and a long-tube runner layout.

Its construction and configuration are intended for performance applications, although the exact stainless-steel grade and tubing specifications should be confirmed with the manufacturer.

5. Horsepower potential

A comparable K-Series megaphone race header is advertised with gains of approximately 19–26 horsepower over a stock header on a race-built engine. That is not a verified result for this particular TSM Race header, but it illustrates the potential of this style of exhaust design.

Actual gains depend heavily on engine displacement, camshafts, compression ratio, intake setup, exhaust diameter, and ECU tuning.

This style of header is particularly well suited to performance K20 and K24 combinations with upgraded camshafts, intake manifolds, and supporting modifications.

Application and fitment

Designed for Honda K-Series performance applications, including K20 and K24 engine combinations. Exact vehicle fitment, engine mount compatibility, and chassis clearance should be verified before purchase.

Bottom line: The TSM Race 4-1 Megaphone Header is a promising upgrade for K-Series enthusiasts chasing stronger high-RPM performance, improved exhaust flow, and a more aggressive exhaust note. Its greatest potential is in a properly tuned, naturally aspirated performance build.