Milltek i20 N Downpipe 2.76″ De-Cat – Hyundai BC3 SSXHY165

Milltek i20 N Downpipe SSXHY165 – 2.76″ Large-Bore De-Cat

The Milltek i20 N downpipe SSXHY165 is a 70mm / 2.76″ large-bore de-cat downpipe designed specifically for the Hyundai i20 N 1.6 T-GDi 204PS with factory OPF/GPF equipment. Manufactured from T304L stainless steel, it replaces the original primary catalytic-converter section for dedicated motorsport and track-focused applications.

The SSXHY165 package includes the Milltek MSHY111 primary catalyst bypass downpipe and MSHY112 flex connecting pipe. It is designed to connect to either the original Hyundai OPF/GPF exhaust section or the corresponding Milltek Sport OPF/GPF section, allowing owners to upgrade the front section without necessarily replacing the complete exhaust system.

With its larger 70mm bore, the SSXHY165 replaces the factory downpipe and primary catalyst section with a freer-flowing motorsport component. View the official Milltek SSXHY165 specification.

It is important to distinguish this product from an OPF/GPF delete. SSXHY165 bypasses the primary catalytic converter but does not itself remove the OPF/GPF. Milltek offers a separate OPF/GPF bypass component for customers building a different exhaust configuration.

What Is Included With Milltek SSXHY165?

Milltek identifies two principal components in the SSXHY165 system:

• MSHY111 – Downpipe with Primary Cat Bypass
• MSHY112 – Flex Connecting Pipe

Milltek also lists a dedicated fitting kit/documentation for SSXHY165.

The inclusion of a flex connecting section is particularly relevant on a turbocharged front-wheel-drive vehicle, where the exhaust connection needs to accommodate normal engine and exhaust-system movement.

70 mm / 2.76″ Large-Bore Construction

One of the defining specifications of the Milltek Hyundai i20 N downpipe is its 70 mm pipe diameter, equivalent to approximately 2.76 inches. Milltek confirms this measurement directly in its product catalogue.

A performance downpipe sits immediately downstream of the turbocharger and therefore forms an important section of the exhaust path on a turbocharged engine.

Replacing the catalyst-containing factory section with a less restrictive race component changes this section of the exhaust system, which is why de-cat downpipes are commonly selected for dedicated performance and motorsport builds.

However, no specific horsepower or torque increase for SSXHY165 is published on Milltek’s product page, so we would not advertise an unsupported bhp figure. Actual results will depend on the complete vehicle specification, ECU calibration and supporting modifications.

T304L Stainless-Steel Construction

Milltek states that its exhaust products are manufactured using 304L stainless steel, chosen for durability in demanding exhaust-system environments. The company also states that its performance exhaust products are manufactured in the UK.

For UK performance cars exposed to rain, winter moisture and road contamination, quality stainless-steel exhaust construction is a useful advantage compared with lower-grade materials.

Designed for the Hyundai i20 N 1.6 T-GDi

Milltek officially lists SSXHY165 for:

Hyundai i20 N 1.6 T-GDi 204 PS – OPF/GPF-equipped cars – 2021 onwards.

Hyundai’s own technical information confirms that the production i20 N combines a 1.6-litre turbocharged GDi petrol engine, 204 PS and a six-speed manual transmission.

The model belongs to Hyundai’s third-generation BC3 family, while Hyundai’s navigation data separately identifies the performance model as BC3N.

Vehicle-data sources commonly identify the 1,598 cc i20 N-specific engine as G4FV. Some aftermarket catalogues use the broader Smartstream G4FP designation, so VIN/registration verification is sensible when engine-code matching is critical.

Fits OE and Milltek OPF/GPF Exhaust Sections

A particularly useful feature of SSXHY165 is that Milltek specifies compatibility with both the original equipment OPF/GPF section and Milltek Sport OPF/GPF sections.

This allows the downpipe to form part of several exhaust build strategies rather than requiring the customer to purchase a complete Milltek system at the same time.

For example, an owner preparing a dedicated track car may initially retain other parts of the exhaust and then add compatible Milltek components later.

Always check the actual exhaust already installed, particularly on a used or previously modified i20 N.

Important: De-Cat Versus OPF/GPF Delete

The terminology around modern exhausts can easily cause incorrect orders.

SSXHY165 bypasses the primary catalytic converter.

Milltek separately sells SSXHY163 as its non-resonated OPF/GPF bypass. They are therefore different products with different positions/functions in the exhaust system.

This is worth stating clearly on the product page because many competing listings simply use terms such as “de-cat”, “GPF delete” and “downpipe” without explaining exactly which emissions device the component replaces.

Motorsport / Track Application – Not UK Road Approved

Is the Milltek SSXHY165 road legal?

No.

Milltek categorises SSXHY165 as:

• Race Product: Yes
• E-marked: No

More importantly for UK buyers, this component removes the vehicle’s original primary catalytic converter.

Current DVSA MOT guidance states that on applicable modern petrol vehicles, manufacturer-fitted emissions-control equipment that is missing, obviously modified or obviously defective constitutes a major MOT defect. Government guidance also states that the MOT checks whether a catalyst that was fitted as standard is missing.

For that reason, this product should be marketed clearly as a motorsport/race/off-road competition component, not as a road-legal exhaust upgrade.

For customers requiring an emissions-compliant alternative, Milltek also lists an HJS ECE-approved sports-catalyst downpipe for the i20 N separately.

Milltek i20 N Downpipe Installation

Milltek quotes approximately 3–4 hours fitting time including removal of the original system.

Because the work involves the turbo/downpipe area, emissions components and exhaust sensors, professional installation by an experienced performance exhaust workshop is strongly recommended.

Before installation, the workshop should confirm:

• exact model and engine
• existing downpipe configuration
• OPF/GPF configuration
• oxygen-sensor locations
• condition of exhaust fasteners and joints
• whether the rest of the exhaust is original or modified

Do not assume that a modified vehicle retains its original exhaust arrangement.

ECU Calibration

Milltek does not state on the SSXHY165 product page that an ECU calibration is included or required.

Because this product physically removes the primary catalytic converter, owners of modified cars should discuss the complete vehicle calibration and sensor strategy with a competent tuner. We would not promise that a warning light will or will not occur because this can depend on calibration and vehicle configuration.

Why Choose Milltek for an i20 N Performance Build?

Building a more complete Hyundai i20 N performance package? Browse our performance exhaust systems, Hyundai performance parts and other compatible intake, intercooler, suspension and braking upgrades. You can also read our performance exhaust pipe guide for more information on exhaust diameter, construction and choosing the correct system for your build.

SSXHY165 offers a known, vehicle-specific solution rather than a generic fabricated pipe.

Key reasons an i20 N track-build owner may select it include:

• correct vehicle-specific design
• known 70 mm bore
• T304L stainless-steel construction
• separate flex connecting pipe
• compatibility with OE or Milltek OPF/GPF sections
• clear Milltek manufacturer part number
• integration with other Milltek i20 N exhaust components

For a modified i20 N, that can make planning the complete exhaust system much easier than mixing unidentified components.

Buy the Milltek i20 N Downpipe SSXHY165 in the UK

Order the Milltek i20 N downpipe SSXHY165 from Performance Car Parts UK for compatible Hyundai i20 N 1.6 T-GDi 204 PS OPF/GPF-equipped vehicles.

Please confirm the car’s registration, model year and existing exhaust configuration before ordering if there is any uncertainty.

Performance Car Parts UK reference SKU: FMSSXHY165
Milltek manufacturer part number: SSXHY165

Remember that this is a primary catalytic-converter bypass race product and is not suitable for UK public-road use.

Key Features

• Genuine Milltek Sport performance exhaust component
• Designed for Hyundai i20 N 1.6 T-GDi 204 PS
• Milltek manufacturer part number SSXHY165
• Performance Car Parts / Forge reference FMSSXHY165
• 70 mm / 2.76″ pipe diameter
• Large-bore turbo downpipe
• Primary catalytic-converter bypass / de-cat configuration
• Fits original-equipment OPF/GPF section
• Also compatible with corresponding Milltek OPF/GPF exhaust sections
• T304L stainless-steel construction
• Includes MSHY111 downpipe and MSHY112 flex connecting pipe
• Milltek estimated installation time: approximately 3–4 hours
• Classified by Milltek as a Race Product
• Not E-marked
• Intended for motorsport/off-road competition application rather than public-road use

Specifications supported by Milltek’s current catalogue.

Technical Specifications

FAQs

Does the Milltek SSXHY165 fit the Hyundai i20 N?

Yes. Milltek lists SSXHY165 for the Hyundai i20 N 1.6 T-GDi 204 PS with OPF/GPF from 2021 onwards. Always verify previously modified vehicles before ordering.

Is the Milltek SSXHY165 road legal in the UK?

No. Milltek classifies SSXHY165 as a race product and states that it is not E-marked. It bypasses the primary catalytic converter, so it should be treated as a motorsport/off-road competition component rather than a UK road-use part.

Does SSXHY165 remove the OPF/GPF?

No. SSXHY165 is the primary catalytic-converter bypass and can connect to the OE or Milltek OPF/GPF section. Milltek sells a separate OPF/GPF bypass, SSXHY163.

What diameter is the Milltek i20 N downpipe?

Milltek specifies 70 mm, equivalent to approximately 2.76 inches.

What is included with SSXHY165?

Milltek lists MSHY111 downpipe with primary catalyst bypass and MSHY112 flex connecting pipe as the two main components.

Will this downpipe fit the standard Hyundai exhaust?

Yes, Milltek states that the primary cat bypass can connect to the original-equipment OPF/GPF section as well as compatible Milltek Sport OPF/GPF sections.

How long does the Milltek i20 N downpipe take to install?

Milltek gives an estimated installation time of approximately 3–4 hours including removal of the original system. Actual fitting time can vary with vehicle condition and previous modifications.

Does the Milltek downpipe require an ECU remap?

Milltek does not state on the SSXHY165 product listing that an ECU calibration is supplied or mandatory. Because the primary catalyst is being removed, owners should discuss the vehicle’s sensor and ECU calibration requirements with a competent performance tuner before installation.