BMW 420i 420ix B48 Decat Downpipe - SS304 Stainless Steel Performance Upgrade
Unlock power, response and sound from your BMW 420i or 420ix with this B48 decat downpipe. Engineered from SS304 aircraft-grade stainless steel and TIG welded in-house, this high-flow 3.5 inch downpipe replaces the restrictive factory catalytic converter to deliver faster turbo spool, sharper throttle response and an aggressive exhaust note. Designed for the 2.0 B48 turbo engine in 163 bhp, 184 bhp and 252 bhp variants, it is the proven performance downpipe upgrade for the BMW 4 Series.
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Why choose this B48 decat downpipe
- SS304 aircraft-grade stainless steel - corrosion resistant and built to last
- TIG welded in-house for strength, precision and clean flow paths
- One-piece top section with no welds - stronger, smoother flow than cheaper alternatives
- True 3.5 inch from the turbo - helps reduce backpressure and speeds up turbo spool
- Real-world gains - typically 12 to 15 bhp with noticeably sharper throttle response
- Deeper, more aggressive exhaust tone that still sounds refined
- Lower temperatures and reduced exhaust backpressure - eases turbocharger workload and improves cylinder charge
- Significant weight saving versus the factory catalytic converter
- Mandrel-bent for maximum internal diameter and excellent gas flow without sacrificing mid-range torque
- Sleeved lower connection - please check your vehicle’s connection type before ordering
Fitment - B48 2.0 turbo petrol
BMW 420i and 420ix with the B48 engine, plus the following B48-equipped models:
- BMW 230i and 230ix F22 and F23 - 2016 onwards
- BMW 320i, 330i, 330ix and 330e F30 F31 F34 - 2016 onwards
- BMW 430i and 430ix F32 F33 F36 - 2016 onwards
- All B48 2.0 litre petrol turbo engines
Important compatibility note
This will not fit 2018+ models with a PPF unless the PPF has been coded out and removed. The connection at the bottom is sleeved - please check this before ordering as 2018 models are different. Contact us if you are unsure.
Installation and our recommendation
Professional installation is recommended, as exhaust tolerances vary between cars and space can be tight. Feedback from customers is that this B48 downpipe is straightforward to fit. For fitting, we can help - book installation with Nforcd in Warwickshire. Request a quote at Sales@nforcd.com.
Our experience and customer feedback
We have installed and used this B48 decat downpipe ourselves and the results are excellent - quicker turbo response, stronger mid-range pull and a seriously addictive sound. Customer feedback has been consistently positive for both fit and performance.
Recommended extras
We recommend adding Lambda Sensor Spacer(s) to help prevent the engine management light in most cases. These are available separately on our site.
Warranty
Supplied with a lifetime warranty for peace of mind.
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