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 AMGNew 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.