Arrow Racing Mid-Pipe (without CAT) Stainless Steel KTM RC 390 2017-2020 71667MI

Engineered exclusively for race use, the Arrow Racing mid-pipe 71667MI is a track-focused stainless steel link pipe designed to unlock the full exhaust potential of your KTM RC 390 (2017-2020). Cleared for competition and built without a catalytic converter, this mid-pipe removes a key restriction in the exhaust path, delivering sharper throttle response and a measurable performance gain — all within a race-legal, track-only configuration.

Key Features

• Race-use only certification — purpose-built for track environments where road regulations do not apply, giving you the freedom to extract maximum performance without compromise.
• Stainless steel construction ensures exceptional heat resistance and longevity even under sustained high-rev track conditions.
• Retains the original header, reducing installation complexity and overall cost while transforming the exhaust mid-section.
• Compatible with both the OEM slip-on silencer and Arrow slip-on series (e.g. 71860), making it a versatile foundation for staged exhaust builds.
• Weighs just 0.5 kg, contributing to a reduction in overall exhaust system mass and improving handling feel.
• ECU remapping strongly recommended after fitment to ensure the fuelling map matches the new exhaust flow characteristics and to protect engine longevity.

Performance and Build Quality

The 71667MI mid-pipe sits between the original KTM header and your chosen silencer, eliminating the catalytic converter that restricts exhaust gas flow on the standard system. The result is improved throttle response from lower in the rev range and a more direct power delivery that suits both track days and dedicated circuit racing. Stainless steel is the material of choice here for good reason: it withstands the thermal cycling inherent in hard track use, resists corrosion from condensation during cool-down periods, and maintains its structural integrity lap after lap.

Compatibility and Installation

Because the 71667MI retains the factory header, installation is straightforward and does not require additional brackets or modifications to the front of the exhaust system. The pipe interfaces cleanly with Arrow's own slip-on range, particularly the 71860 series, allowing you to pair it with an Arrow end can for a full-system performance boost. It is equally compatible with the standard KTM silencer if you wish to upgrade the mid-section alone. Arrow strongly advises an ECU remap following installation to optimise fuelling, throttle response, and to prevent running lean under race conditions.

Fitment and Compatibility

• KTM RC 390 — model years 2017, 2018, 2019, 2020
• Compatible with original KTM header
• Compatible with OEM slip-on silencer
• Compatible with Arrow slip-on series (e.g. part number 71860)

Specifications