Milltek Downpipe & De-cat for BMW 3 Series F30 328i M Sport Automatic (without Tow Bar, Non-xDrive & N20 Engine Only) (2012-2015) – Maximum Flow, Motorsport Use
This is Milltek's large-bore downpipe and de-cat for the BMW 4 Series F32 428i Coupé (Automatic Gearbox, without Tow Bar, Non-xDrive & N20 Engine 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 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: 76.2mm (3")
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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
- 76.2mm (3") 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
- BMW 3 Series F30 328i M Sport Automatic (without Tow Bar, Non-xDrive & N20 Engine Only) (2012-2015)
- BMW 4 Series F32 428i Coupé (Automatic Gearbox, without Tow Bar, Non-xDrive & N20 Engine Only) (2014-2016)
- BMW 4 Series F32 428i Coupé (Manual Gearbox, without Tow Bar, Non-xDrive & N20 Engine Only) (2014-2018)
Not suitable for: the BMW 3 Series F80 M3 & M3 Competition Saloon (Non OPF/GPF Models Only), which needs the Milltek Downpipe & De-cat BMW 3 Series F80 M3 & M3 Comp Saloon Non OPF/GPF 14-18; the BMW 3 Series G80 M3 & M3 Competition S58 3.0 Turbo (North American/ROW Non-OPF/GPF Cars Only), which needs the Milltek Secondary Catalyst Bypass BMW 3 Series G80 M3 & M3 Comp S58 3.0 Turbo (North American & ROW Non-OPF/GPF Cars Only) 21+; the BMW 3 Series E30 M3, which needs the Milltek Full Exhaust & Cat Bypass BMW 3 Series E30 M3 87-92.
Installation
Before ordering, note: Requires a Stage 2 ECU remap and must be fitted with a Milltek Sport cat-back system. Fits manual and auto models. 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 Cat-back Exhaust BMW 3 Series F30 328i M Sport Automatic (without Tow Bar, Non-xDrive & N20 Engine Only) 12-15.
Will it fit the BMW 4 Series F32 428i Coupé (Automatic Gearbox, without Tow Bar, Non-xDrive & N20 Engine Only)?
Yes. Milltek lists this part for the BMW 4 Series F32 428i Coupé (Automatic Gearbox, without Tow Bar, Non-xDrive & N20 Engine Only) as well as the other models in the fitment list above.
Does it fit the BMW 3 Series F80 M3 & M3 Competition Saloon (Non OPF/GPF Models Only)?
No. For that car, choose the Milltek Downpipe & De-cat BMW 3 Series F80 M3 & M3 Comp Saloon Non OPF/GPF 14-18.
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: "Requires a Stage 2 ECU remap and must be fitted with a Milltek Sport cat-back system. Fits manual and auto models". Without suitable software the engine management is likely to log faults.
Can I use it with my standard exhaust?
No. Milltek states it must be fitted with the matching Milltek system, so budget for the cat-back as well.
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.
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.
