Milltek Filter-back Exhaust for BMW 1 Series M135i xDrive 5 Door (F40 OPF/GPF Equipped) (2019 onwards) – Sharper Sound, Filter Retained
This is Milltek's particulate filter-back system for the BMW 1 Series M135i xDrive 5 Door (F40 OPF/GPF Equipped). It replaces everything downstream of the factory diesel or petrol particulate filter with wider-bore pipework and re-tuned silencers, cutting back pressure and sharpening the exhaust note. The filter itself is left exactly where the manufacturer fitted it, so emissions equipment is unaffected. It's offered in 9 tailpipe finishes, so you can pick the setup that suits how the car's used.
It's the right choice if you want a sportier sound and a genuine, if modest, flow improvement on a filter-equipped car, without going anywhere near the parts of the system that keep it emissions-compliant.
Specifications
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System Type: Particulate Filter-back
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Pipe Diameter: 76.2mm (3")
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EC Approved: Yes
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Race System: No
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
- Fits behind the factory particulate filter, which stays in place
- Choice of 9 tailpipe finishes: GT-100 Brushed Titanium, GT-100 Burnt Titanium, GT-100 Cerakote Black, GT-100 Polished, GT-115 Burnt Titanium, GT-115 Cerakote Black, GT-115 Polished, GT-115 Titanium and more
- EC approved
- Designed, developed and manufactured in the UK by Milltek Sport
Fitment
- BMW 1 Series M135i xDrive 5 Door (F40 OPF/GPF Equipped) (2019 onwards)
Not suitable for: the BMW 1 Series M135i xDrive 5 Door (F70 OPF/GPF Equipped), which needs the Milltek Filter-back Exhaust BMW 1 Series M135i xDrive 5dr F70 OPF/GPF 24+; the BMW 1 Series 128ti 5 Door (F40 OPF/GPF Equipped), which needs the Milltek Filter-back Exhaust BMW 1 Series 128ti 5dr F40 OPF/GPF 21+.
Installation
The fitting time varies by version; see the specification table for the option you choose. Some versions: Maxton x Milltek - OPF/GPF Back System with Quad GT-100 Brushed Titanium Trims - ECE Approved (OE System Requires To Be Cut For Installation) - MUST BE Fitted with Maxton Diffuser. Some versions: Maxton x Milltek - OPF/GPF Back System with Quad GT-100 Burnt/Blue Titanium Trims - ECE Approved (OE System Requires To Be Cut For Installation) - MUST BE Fitted with Maxton Diffuser. Some versions: Maxton x Milltek - OPF/GPF Back System with Quad GT-100 Cerakote Black Trims - ECE Approved (OE System Requires To Be Cut For Installation) - MUST BE Fitted with Maxton Diffuser. Some versions: Maxton x Milltek - OPF/GPF Back System with Quad GT-100 Polished Trims - ECE Approved (OE System Requires To Be Cut For Installation) - MUST BE Fitted with Maxton Diffuser. We recommend professional fitting on a ramp. Once fitted, check the tailpipe alignment and re-check all clamps after the first few hundred miles.
Which tailpipe finishes are available?
You can choose from: GT-100 Brushed Titanium, GT-100 Burnt Titanium, GT-100 Cerakote Black, GT-100 Polished, GT-115 Burnt Titanium, GT-115 Cerakote Black, GT-115 Polished, GT-115 Titanium, JET-115 Carbon Fibre. The finish is cosmetic and does not change the sound.
Does it fit the BMW 1 Series M135i xDrive 5 Door (F70 OPF/GPF Equipped)?
No. For that car, choose the Milltek Filter-back Exhaust BMW 1 Series M135i xDrive 5dr F70 OPF/GPF 24+.
Is it road legal?
Every version of this part is listed by Milltek as EC approved.
Do I need a remap?
No. It fits behind the factory particulate filter, so no software changes are needed.
Does it keep the factory particulate filter?
Yes. It fits behind the factory particulate filter, which stays in place.
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.
