Milltek Downpipe & De-cat for Audi S3 2.0TFSI Quattro Saloon/Sedan 310PS & 333PS 8Y (OPF/GPF Models Only) (2020 onwards) – Maximum Flow, Motorsport Use
This is Milltek's large-bore downpipe and de-cat for the Audi S3 2.0TFSI Quattro Sportback 310PS & 333PS 8Y (OPF/GPF Models Only). It replaces the factory downpipe with a larger-bore pipe and removes the catalytic converter entirely, clearing the single most restrictive point in the exhaust for the biggest flow gain available at this position in the system. It's usually fitted alongside a Stage 2 remap, since the ECU needs to be told to expect the different readings the lambda sensors give once the cat's gone. It's offered in versions to suit the factory or a Milltek system, so you can pick the setup that suits how the car's used.
It's built for owners already committed to a serious power upgrade rather than a casual bolt-on, so pair it with the matching Milltek cat-back system for the full effect.
Because it removes the cat, it's intended for off-road and competition use. A de-catted car will fail an MOT emissions test and isn't legal to use on UK roads.
Specifications
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System Type: Large-bore Downpipe and De-cat
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Pipe Diameter: 94mm (3.7")
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EC Approved: No
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Race System: Yes
Key Features
- Made from T304L aircraft-grade stainless steel, which is anti-magnetic and resists discolouration
- Mandrel-bent pipework keeps a constant diameter through every bend for unrestricted flow
- 94mm (3.7") pipework
- Removes the factory catalyst for maximum flow (off-road and competition use only)
- Designed, developed and manufactured in the UK by Milltek Sport
Fitment
- Audi S3 2.0TFSI Quattro Saloon/Sedan 310PS & 333PS 8Y (OPF/GPF Models Only) (2020 onwards)
- Audi S3 2.0TFSI Quattro Sportback 310PS & 333PS 8Y (OPF/GPF Models Only) (2020 onwards)
- Volkswagen Golf Mk8 R 2.0 TSI 320PS (GPF Equipped Models Only) (2021-2024)
- Volkswagen Golf Mk8.5 R (333ps OPF/GPF Equipped Models Only) (2024 onwards)
- Seat Cupra Formentor 2.0TFSI 4Drive 310PS & 333PS (MQB EVO EA888.4 OPF/GPF Vehicles) (2021 onwards)
- Volkswagen Tiguan R 320ps EA888.4 MQB EVO (OPF/GPF Models Only) (2021 onwards)
- Volkswagen T-Roc R 2.0TSI 300ps (MQB EVO Models with OPF/GPF) (2022 onwards)
Not every version fits every car in this list. Check the fitment shown for the option you select.
Not suitable for: the Audi S3 2.0TFSI Quattro Saloon/Sedan 310PS 8Y (North American/Non-OPF Models Only), which needs the Milltek Downpipe & De-cat Audi S3 2.0TFSI Quattro Saloon 310PS 8Y (North American & Non-OPF) 22+.
Installation
The fitting time varies by version; see the specification table for the option you choose. Some versions: 94mm/3.7inch ID Turbo Outlet to 80mm/3.15inch Downpipe with Decat/OPF Bypass - Fits with Milltek Cat Back System Only (Requires Stage 2 ECU Remap). Some versions: 94mm/3.7inch ID Turbo Outlet to 80mm/3.15inch Downpipe with Decat/OPF Bypass - Fits with OE System Only (Requires Stage 2 ECU Remap). This work involves removing parts close to the turbo and engine, so we recommend fitting by a specialist with a ramp and suitable software support.
Upgrade Further
Also available from Milltek for this car: Milltek Filter-back Exhaust Audi S3 2.0TFSI Quattro Saloon 8Y OPF/GPF 20+.
Will it fit the Audi S3 2.0TFSI Quattro Sportback 310PS & 333PS 8Y (OPF/GPF Models Only)?
Yes. Milltek lists this part for the Audi S3 2.0TFSI Quattro Sportback 310PS & 333PS 8Y (OPF/GPF Models Only) as well as the other models in the fitment list above.
Does it fit the Audi S3 2.0TFSI Quattro Saloon/Sedan 310PS 8Y (North American/Non-OPF Models Only)?
No. For that car, choose the Milltek Downpipe & De-cat Audi S3 2.0TFSI Quattro Saloon 310PS 8Y (North American & Non-OPF) 22+.
Is it road legal?
No. Removing the catalyst means the car will fail an MOT emissions test, so it is for off-road and competition use only.
Do I need a remap?
Yes. Milltek notes: "Fits Milltek Cat Back Only, Stage 2 Remap Required". Without suitable software the engine management is likely to log faults.
Can I use it with my standard exhaust?
It depends on the version. Some are made for the factory (OE) system and others for the Milltek cat-back, so check the notes for the option you choose.
Will removing the cat cause a warning light?
Without suitable software it is likely to, as the ECU expects the readings a working catalyst gives. This is why Milltek pairs it with a remap.
How long does it take to fit?
It depends on the version. Milltek's fitting time for each option is shown in its specification table.
What is it made from?
T304L aircraft-grade stainless steel, which is anti-magnetic and resists discolouration better than lower grades.
Is there a warranty?
Yes. Milltek products are covered against defects in materials and workmanship. Contact us with your order number if you have a problem.
