M117 Tri-Y Exhaust System for Mercedes-Benz W/C126

M117 Tri-Y Exhaust System for Mercedes-Benz W/C126

Rare Factory-Type Performance Manifold Upgrade for 500/560 V8 Models

Offered here is a desirable Mercedes-Benz Tri-Y exhaust system designed for M117-powered W126 S-Class sedans and C126 coupes (1986-1991). This system includes authentic Mercedes Tri-Y tubular headers, a ceramic-coated downpipe and Y-pipe, EGR components, and a partial rear exhaust section originally removed from a 1991 Japan-market 560SEL AMG.

This is an original Mercedes design—not a reproduction—ensuring factory-correct fitment and performance on LHD W126 models equipped with the 500 or 560 M117 V8.

Performance & Benefits

The factory Tri-Y headers are widely regarded as the most desirable OEM performance upgrade for the M117 V8, providing a free-flowing alternative to the restrictive U.S.-market log manifolds. When fitted to a U.S.-spec 500/560, these headers are known to offer:

• +25–30 estimated horsepower gain

• Reduced backpressure for improved torque

• Faster exhaust gas evacuation

• Better throttle response

• Enhanced top-end power without tuning changes

The design pairs cylinders in a tuned “Y” configuration to promote scavenging, reducing exhaust turbulence and allowing the M117 to breathe more efficiently. These manifolds were favored by AMG and are often found on high-spec Euro performance builds.

Components & Condition

Included items have been recently ceramic coated for improved heat control, corrosion resistance, and longevity. Most of the system is bolt-on for the W126 560SEL, and the headers fit both sedan and SEC coupe models.

Included Components

• Authentic Mercedes Tri-Y headers (4 pieces)

• Downpipe + Y-pipe (ceramic coated)

• EGR valve & covers

• Metal Cat catalytic converter with welded O₂ bung

• Custom cat-delete extension pipe with matching flanges

• Partial rear exhaust section from Japan-market 560SEL AMG
  New mounting hardware included

Exclusions

• Rear muffler not included

Mercedes OEM Header Part Numbers

• PN 117 142 45 02

• PN 117 142 46 02

• PN 117 142 48 02

• PN 117 142 51 02

Fitment

• Chassis: W126 (SE/SEL) and C126 (SEC)

• Engines: M117 500 & 560 V8

• Model Years: 1986–1991 (Late Gen II)

• Steering: Fits LHD models

• Direct Bolt-In: Complete system bolts into 560SEL

• Adaptation: Can fit 500 models; shop installation recommended

This setup is ideal for owners seeking OEM-plus performance, AMG-style upgrades, or period-correct modifications.

Authenticity

The system retains original Mercedes-Benz stampings on the header castings and pipes, confirming factory origin. These pieces are not aftermarket reproductions, and their presence on Japan-market AMG vehicles underscores their desirability.

Why These Headers Matter

Unlike the common U.S. cast manifolds, these tubular Tri-Y units:

• Flow similarly to early AMG headers

• Provide measurable gains without ECU tuning

• Reduce under-hood heat when ceramic coated

• Improve engine longevity by reducing exhaust stress

This makes them a highly sought-after upgrade for collectors, performance enthusiasts, and owners building OEM-plus resto-mods.