Borg Warner 178787 | S400SX .90 A/R T4 Twin-Scroll Turbine Housing (87mm) – 7.3 Powerstroke & Performance Diesel

Upgrade your turbo performance with the genuine BorgWarner 178787 S400SX turbine housing. Featuring a precision 0.90 A/R ratio and T4 divided twin-scroll design, this housing delivers an excellent balance of quick spool-up and strong top-end power — making it a popular choice for 7.3 Powerstroke builds and high-performance diesel applications.

Engineered specifically for S400 / S400SX series turbos with an 87mm turbine wheel, the .90 A/R provides responsive boost and efficient exhaust flow while keeping drive pressure in check. The T4 twin-scroll inlet improves exhaust pulse separation and cylinder scavenging, while the V-band outlet makes installation and service fast and leak-free.

Key Features & Benefits:

• 0.90 A/R Ratio — Outstanding balance of mid-range response and high-RPM flow
• T4 Divided Twin-Scroll Inlet — Reduces turbo lag, lowers drive pressure, and improves scavenging
• V-Band Outlet (3.5" / 4.21 Marmon style) — Easy, reliable, gasket-free connection
• Robust Cast Iron Construction — Built for extreme heat and long-term durability in diesel applications
• External Wastegate Compatible — Ideal for performance and competition setups
• Direct Fit for S400 turbos with 87mm turbine wheel (S472, S475, S476, S480, S482, and similar)

Perfect For:

• 7.3 Powerstroke S400 turbo upgrades and custom builds
• Single turbo street/strip and towing setups
• Compound turbo systems (high-pressure or low-pressure charger)
• Custom diesel performance and engine swap projects

Note: This is the turbine housing only. Turbo cartridge, compressor housing, and wastegate actuator are sold separately.