Click to open expanded view

Milltek 80mm Secondary Catalyst Bypass BMW G90 / G99 M5

SKU: SSXBM1415
Price
$2,561.58
Currently Backordered - You can still place your order and we'll ship your order as soon as the product is back in stock!

Need some product help?
Installation Services

Don’t worry about the hassle — let our expert team at Forza Motorworks handle the installation for you. Our professional installation ensures everything fits and operates exactly as intended, giving you clean, factory-quality results, proper wiring or mounting, and avoiding the risks of DIY mistakes. You’ll save time, avoid frustration, and get peace of mind knowing the job is done right the first time. Contact us to learn about our installation services and enjoy a seamless upgrade from day one.

FAQ

Shipping Information
For items that are in stock, purchases made after 9am EST will be usually be shipped out in the next 1-2 business days. Please inquire to confirm lead times if you have specific time constraints. Orders will be sent via signature required at our discretion unless otherwise requested. 

International Shipping
Any and all customs duties, taxes, import fees, and/or tariffs assessed in connection with the purchase shall be the sole responsibility of the customer/end user.

Cancellations / Returns

Original sales receipt or order number must accompany all return requests.

Forza Motor Works accepts returns for exchange, store credit, or refund within fourteen (14) calendar days of the delivery date, subject to the terms and conditions below. After fourteen (14) calendar days, all sales are final unless otherwise approved in writing by Forza Motor Works.

To be eligible for return, products must be in new, unused, unaltered, and resalable condition, including all original packaging, instructions, hardware, documentation, and accessories. Returned items must not show any signs of installation, use, wear, damage, modification, painting, coating, or alteration of any kind.

The following items are non-returnable and non-refundable:

• Special-order products
• Custom-built or made-to-order products
• Products manufactured to customer specifications
• Custom color or finish products
• Manufacturer-direct-shipped products designated as non-returnable
• Products with extended lead times, including but not limited to headers, exhaust systems, wheels, and other special-order performance products
• Any item specifically identified on the product page as non-returnable

Orders for special-order, custom-built, made-to-order, vehicle-specific, or manufacturer-direct-shipped products may not be canceled once the order has been submitted to the manufacturer.

If an item is received damaged during shipping or was shipped incorrectly by Forza Motor Works, Customer Support must be contacted within forty-eight (48) hours of delivery. Claims for shipping damage must include clear photographs of the product, packaging, shipping box, and shipping label at the time of unpacking.

Products determined by Forza Motor Works to have been incorrectly shipped may qualify for replacement, store credit, or refund at our sole discretion. Manufacturer defects are subject to the applicable manufacturer's warranty policies and procedures. Forza Motor Works does not provide any separate product warranty unless expressly stated in writing.

All returns must be authorized prior to shipment and must be assigned a Return Merchandise Authorization (RMA) number. The RMA number must be clearly displayed on the outside of the return package. Returns received without an authorized RMA number may be refused or denied credit.

To obtain a Return Merchandise Authorization (RMA), please contact:

Forza Motor Works
Email: info@forzamotorworks.com

All refunds, exchanges, and store credits are contingent upon inspection and approval of the returned merchandise. Forza Motor Works reserves the right to deny any return that does not comply with this policy.

Approved returns may be subject to a restocking fee of up to twenty five percent (25%) of the purchase price. Original shipping charges are non-refundable. Customer is responsible for all return shipping costs unless the return is the direct result of an error made by Forza Motor Works.

FITMENT, INSTALLATION & PRODUCT USE

Customer is responsible for verifying vehicle compatibility, fitment, and intended use prior to installation. While Forza Motor Works makes reasonable efforts to provide accurate product information and fitment guidance, final responsibility for compatibility rests solely with the customer.

Products that have been installed, test-fitted, modified, painted, coated, damaged, or otherwise used are not eligible for return.

Many aftermarket performance products are intended for off-road, racing, or competition use only and may not be legal for use on public roads in all jurisdictions. Customer is solely responsible for determining compliance with all applicable federal, state, and local laws and regulations.

LIMITATION OF LIABILITY

FORZA MOTOR WORKS SHALL NOT BE LIABLE FOR ANY INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE, OR CONSEQUENTIAL DAMAGES ARISING FROM THE PURCHASE, INSTALLATION, USE, MISUSE, FAILURE, OR INABILITY TO USE ANY PRODUCT SOLD BY FORZA MOTOR WORKS.

FORZA MOTOR WORKS SHALL NOT BE RESPONSIBLE FOR LOSS OF TIME, LOSS OF REVENUE, LOSS OF PROFITS, LOSS OF VEHICLE USE, TOWING CHARGES, RENTAL VEHICLE COSTS, STORAGE FEES, DIAGNOSTIC FEES, INSTALLATION COSTS, REMOVAL COSTS, ALIGNMENT CHARGES, TUNING FEES, SHIPPING EXPENSES, FINES, PENALTIES, PROPERTY DAMAGE, VEHICLE DAMAGE, OR ANY OTHER INCIDENTAL OR CONSEQUENTIAL LOSS OR EXPENSE.

TO THE MAXIMUM EXTENT PERMITTED BY LAW, FORZA MOTOR WORKS' TOTAL LIABILITY FOR ANY CLAIM ARISING FROM THE PURCHASE OR USE OF A PRODUCT SHALL NOT EXCEED THE AMOUNT PAID FOR THE SPECIFIC PRODUCT GIVING RISE TO THE CLAIM.

By placing an order with Forza Motor Works, the customer acknowledges and agrees to all terms and conditions contained herein, including all return, exchange, warranty, and limitation-of-liability provisions.

Product Description

 

 

Enhance the exhaust sound and flow characteristics of your BMW G90 M5 or G99 M5 Touring with the Milltek Sport 80mm Secondary Catalyst Bypass System. Engineered specifically for BMW's 4.4L twin-turbocharged hybrid V8, this performance exhaust upgrade replaces the factory secondary catalytic converter section to reduce exhaust restriction and deliver a more aggressive exhaust note.

Manufactured from premium T304L stainless steel, the Milltek Sport Secondary Catalyst Bypass features 80mm (3.15-inch) mandrel-bent piping designed to promote efficient exhaust gas flow. Its precision-engineered construction provides excellent durability, corrosion resistance, and consistent performance under demanding exhaust temperatures.

The system incorporates left and right secondary catalyst bypass pipes along with an active center section, designed to enhance the exhaust characteristics of the G90/G99 M5 when paired with compatible Milltek performance exhaust components.

Unlike universal exhaust modifications, this system is specifically engineered to integrate with Milltek Sport axle-back and downpipe exhaust systems. Its vehicle-specific design provides precise alignment and utilizes the factory mounting locations and exhaust hangers for straightforward installation.

By eliminating the factory secondary catalytic converters, the Milltek bypass allows more of the M5's twin-turbocharged V8 exhaust character to be heard, particularly during acceleration and higher engine speeds. The system is designed to complement Milltek's performance exhaust range, providing a more engaging exhaust experience.

Designed and manufactured in the United Kingdom, Milltek Sport exhaust components combine precision engineering, high-quality materials, and extensive performance exhaust development experience.

For BMW M5 owners seeking increased exhaust volume, improved exhaust flow, and premium stainless-steel construction, the Milltek Sport 80mm Secondary Catalyst Bypass provides an excellent addition to a compatible Milltek exhaust system.

Fitment Notes

  • Fits 2025+ BMW M5 Sedan (G90) with 4.4L twin-turbocharged hybrid V8

  • Fits 2025+ BMW M5 Touring (G99) with 4.4L twin-turbocharged hybrid V8

  • Designed for North American Specification (NAS) and Rest of World (ROW) vehicles

  • Specifically engineered for use with compatible Milltek Sport axle-back and downpipe exhaust components

  • Includes adapters for connection to the Milltek axle-back exhaust

  • Not designed for direct connection to the factory axle-back exhaust

  • Utilizes factory mounting locations and OEM exhaust hangers

  • No cutting or permanent vehicle modifications required for the specified Milltek configuration

  • Not intended for UK/European GPF/OPF-equipped applications

  • Not compatible with BMW F90 M5 or other BMW 5 Series models

  • Removes factory secondary catalytic converters

  • Not approved for emissions-controlled public-road use where catalytic converter removal is prohibited

  • Professional installation recommended

Included

  • Milltek left-hand secondary catalyst bypass pipe (MSBM459)

  • Milltek right-hand secondary catalyst bypass pipe (MSBM460)

  • Milltek active center section for NAS/ROW vehicles (MSBM461)

  • Milltek adapters to compatible Milltek axle-back exhaust (F5178)

  • Required installation hardware as supplied by Milltek

Sold Separately:

  • Milltek Sport axle-back exhaust system

  • Milltek Sport performance downpipes

Product Specs

  • Manufacturer: Milltek Sport

  • Part Number: SSXBM1415

  • Product Type: Secondary Catalyst Bypass System

  • Vehicle Applications: BMW G90 M5 / G99 M5 Touring

  • Engine: 4.4L Twin-Turbocharged Hybrid V8

  • Vehicle Specification: NAS / ROW

  • Material: T304L Stainless Steel

  • Exhaust Diameter: 80mm (3.15 Inches)

  • Construction: Mandrel-Bent Tubing

  • Configuration: Secondary Catalyst Bypass with Active Center Section

  • Factory Secondary Catalytic Converters: Removed

  • Milltek Axle-Back Compatibility: Yes

  • Milltek Downpipe Compatibility: Yes

  • Factory Axle-Back Compatibility: No

  • Factory Mounting Points: Retained

  • Cutting or Welding Required: No, With Specified Milltek Components

  • Manufacturer-Estimated Installation Time: 2–3 Hours

  • Manufacturer Race Product Classification: No

  • E-Mark Approval: No

  • Country of Manufacture: United Kingdom

Product Features

  • 80mm high-flow exhaust design reduces exhaust restriction and promotes improved exhaust gas flow from the M5's twin-turbocharged V8.

  • Secondary catalyst bypass configuration provides a more pronounced exhaust note by eliminating the factory secondary catalytic converter section.

  • Premium T304L stainless-steel construction offers excellent corrosion resistance, strength, and durability.

  • Integrated active center section is engineered to complement the exhaust characteristics of compatible Milltek performance systems.

  • Direct-fit Milltek exhaust compatibility includes the necessary adapters for integration with compatible Milltek axle-back components.

  • Precision-engineered installation utilizes factory mounting locations and OEM hangers without permanent modifications when installed with the specified Milltek exhaust configuration.