AMS Street Downpipe with GESI Catalytic Converter

2020–2021 Toyota GR Supra B58 3.0L Turbo Engine (USDM Models Only)

AMS.38.05.0001-2

Overview:

The AMS Street Downpipe with GESI Catalytic Converter is a precision-engineered exhaust component designed specifically for the 2020 and 2021 Toyota GR Supra equipped with the B58 3.0L turbocharged engine. This downpipe enhances turbo spool-up and delivers power earlier in the RPM range, improving throttle response and overall driving dynamics. Built for enthusiasts seeking a balance between street-friendly emissions compliance and performance gains, this downpipe integrates a newly formulated catalytic converter substrate that meets stringent emissions standards without compromising flow.

Ideal for drivers who want to unlock the full potential of their Supra’s turbocharged powerplant, the AMS Street Downpipe offers a direct bolt-on upgrade that maintains reliability and drivability while reducing exhaust back pressure for a more efficient turbo system.

Key Features:

Engineered to optimize exhaust flow and turbo response, the AMS Street Downpipe with GESI Catalytic Converter includes:

• Mandrel-bent piping with long, gradual transitions to maintain exhaust gas velocity and minimize back pressure
• EPA-verified ultra-high flow GESI catalytic converter designed specifically for the B58 engine and USDM emissions requirements
• Newly formulated catalytic substrate and wash coat to meet modern emissions standards without sacrificing performance
• Direct bolt-on fitment for 2020 and 2021 Toyota GR Supra models with B58 and B58H 3.0L turbo engines
• Improved turbo spool-up for quicker boost response and enhanced throttle feel
• Durable construction engineered to withstand high exhaust temperatures and daily driving conditions
• Designed to complement other AMS Performance upgrades for a comprehensive performance package

Construction & Design:

The AMS Street Downpipe is crafted from high-quality stainless steel to ensure corrosion resistance and long-lasting durability. The mandrel-bent design features smooth, gradual curves that preserve exhaust gas velocity, preventing turbulence and back pressure buildup that can hinder turbocharger efficiency. The integrated GESI catalytic converter is a purpose-built component, not an off-the-shelf unit, featuring a newly developed substrate and wash coat tailored to meet the latest emissions requirements for USDM Toyota GR Supra models.

Every aspect of the downpipe’s design focuses on maximizing flow while maintaining compliance, making it an ideal upgrade for street-driven vehicles that require emissions-legal components without sacrificing performance.

Performance & Sound

By reducing exhaust back pressure and improving flow dynamics, the AMS Street Downpipe significantly enhances turbo spool-up, allowing the turbocharger to reach boost pressure more quickly. This results in earlier power delivery and a more responsive driving experience. While the catalytic converter maintains emissions compliance, the freer-flowing design also contributes to a more aggressive exhaust note, providing an engaging sound without excessive drone or harshness.

Installation & Fitment:

This downpipe is designed for a direct bolt-on installation on 2020 and 2021 Toyota GR Supra models equipped with the B58 and B58H 3.0L turbo engines (USDM only). Installation requires basic hand tools and moderate mechanical knowledge. No cutting or welding is necessary, and the unit fits seamlessly with the factory exhaust system and turbocharger outlet flange. Professional installation is recommended to ensure proper fitment and to maintain warranty coverage.

What's Included:

• AMS Street Downpipe with mandrel-bent stainless steel piping
• EPA-verified Ultra High Flow GESI Catalytic Converter integrated within the downpipe
• All necessary gaskets and hardware for installation
• Installation instructions

Ideal For:

This downpipe is perfect for Toyota GR Supra owners who want to improve turbo response and overall engine performance while maintaining emissions compliance. It suits enthusiasts looking for a reliable, street-legal upgrade that enhances throttle response and exhaust sound without compromising daily drivability. It also pairs well with other AMS Performance upgrades for those building a comprehensive performance setup.

Emissions Note

The included GESI catalytic converter is EPA-verified and specifically formulated to meet new vehicle emissions requirements for USDM 2020 and 2021 Toyota GR Supra models. This ensures that the downpipe remains street-legal in the United States while delivering improved exhaust flow and performance. It is not an off-the-shelf catalytic converter but a purpose-built unit designed for compliance and efficiency.

AMS Performance is a manufacturer specializing in high-performance aftermarket parts for turbocharged vehicles, including engine upgrades, drivetrain components, suspension enhancements, and aerodynamic modifications. Their products are designed for enthusiasts seeking to increase power output, improve handling, and enhance vehicle aesthetics, particularly for turbocharged platforms.