Armytrix BMW F20/F21 M135i (2012-2015) valvetronic exhaust system
Experience the raw performance and unmistakable sound of your BMW F20/F21 M135i like never before with the ARMYTRIX Valvetronic Exhaust System. Engineered specifically for the 2012–2015 RWD models equipped with the N55B30 turbocharged inline-six, this system delivers aggressive acoustics, improved flow, and wireless valve control for maximum versatility.
Whether you're carving corners or cruising through town, ARMYTRIX transforms your M135i into a more dynamic, visceral driving machine—without sacrificing day-to-day comfort or reliability.
Fitment:
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Model: BMW M135i
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Chassis: F20 / F21
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Years: 2012–2015
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Engine: N55B30 3.0L Turbocharged Inline-6
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Drive Type: Rear-Wheel Drive (RWD Only)
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Body Styles: 5-Door Hatchback / 3-Door Hatchback
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Drive Orientation: Left-Hand Drive & Right-Hand Drive Compatible
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VIN Verification: Strongly recommended to confirm downpipe version and precise fitment
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Note: Tailpipe adjustment may be required depending on rear bumper style; quad-tip configuration requires compatible aftermarket diffuser (contact us before ordering)
Key Features:
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Wireless Valvetronic Control: App-based operation via OBDII port—switch between stealth and sport with a tap
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Main Pipe Diameter: 3.0” – optimised for power and turbo spool
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Exhaust Tips: Dual 2.5” – available in polished or black finishes
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Direct Bolt-On Installation: No cutting or welding required; all hardware included
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Smart CEL Prevention: Exclusive Armytrix fault code clearing module greatly reduces the chance of Check Engine Light (CEL) when paired with high-flow or decat setups
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Premium Construction: Crafted from high-grade stainless steel for superior durability, heat resistance, and long-term performance
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Plug-and-Play Design: OBDII control module slashes install time by 30% compared to traditional wired systems
Valvetronic Sound Modes:
Take command of your M135i’s exhaust character with adjustable valve control via the Armytrix app or included wireless remote:
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Valves Closed: Refined and quiet for daily driving or early morning starts
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Valves Open: Loud, aggressive tone for spirited driving and full performance experience
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Adaptive Control: System responds to RPM and throttle input for dynamic sound modulation
CEL Prevention & System Integration:
Included with the full system is a dedicated Armytrix OBDII module that:
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Clears fault codes related to catalytic converter or OPF deletion
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Minimises the likelihood of a CEL, even with high-flow or catless downpipes
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Seamlessly integrates with vehicle electronics for a hassle-free experience
Why Choose ARMYTRIX for Your BMW M135i?
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Fully wireless valve control via smartphone and OBDII connection
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Proven performance gains with signature ARMYTRIX sound
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Enhanced aesthetics with dual 2.5” tips and optional quad-tip configuration
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Engineered specifically for RWD F20/F21 M135i models
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CEL-reducing technology for smoother operation with modified exhaust setups
Give Your M135i the Sound, Style, and Performance It Deserves
Perfectly tailored for the N55-powered F20/F21 chassis, the ARMYTRIX Valvetronic Exhaust System elevates your M135i to new heights. From the aggressive sound profile to the intelligent valve control and premium craftsmanship, this system redefines what your BMW hatchback is capable of.
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T&C's
T&C's
All purchases on this website our subject to our Terms and Conditions. Please ensure you have read and understood these before making a purchase. If you have any questions, please feel free to contact us and we will endeavour to answer any questions you may have.
PLEASE BE AWARE: Sports cats can NOT legally be installed on a vehicle for use on a public road that was manufactured after 1st March 2001 unless type ECE 103R approved - this can be identified in either the product description and/or in the Technical Information section listed. If you have any doubt on this approval, please contact us immediately for confirmation. Fitting a De-Cat/Cat Bypass, DPF delete/bypass or GPF delete/bypass to a vehicle that is to be used on UK roads will cause the vehicle to fail the MOT emissions test, therefore rendering it unroadworthy and illegal to be used on the road. Therefore, any such products are strictly sold as off-road or motorsport use only and NOT for road use. The vehicle should be transported from place to place via a trailer, flatbed or other recovery means.
Stock Availability
Stock Availability
Due to the high volume of custom orders and special requests we receive daily, it’s not always possible to have every item readily available in our warehouse at all times. While we strive to maintain stock for popular products, some items may require additional processing time. If you need a product urgently, we highly recommend reaching out to our sales team here before placing your order to confirm availability and estimated delivery times.
Please Note:
- Orders with both in-stock and backorder or out-of-stock products will be dispatched once all products are available to ship together.
- Contact our sales team if you want your parts fitted to your vehicle at our Bristol Headquarters.
- Shipping estimates are based on courier delivery times and don't include time to despatch.
Delivery & Returns
Delivery & Returns
At AT Store, we understand the importance of timely delivery when it comes to your orders. Our goal is to have your products shipped on the same day we receive your order. We prioritise efficiency and strive to provide you with a seamless delivery experience.
Same-Day Shipping
We aim to dispatch your orders promptly to ensure minimal waiting time for our customers. Orders received before 15:00 (GMT) on business days will typically be processed and shipped on the same day. Orders received on weekends/holidays will be processed on the next business day.
Communication on Delays
While we make every effort to ship your orders promptly, there may be unforeseen circumstances or stock availability issues that could cause delays. In such cases, a dedicated member of our sales team will personally reach out to you to inform you of any delays and provide updates on the status of your order.
Akrapovic Products Lead Time
Please note that for Akrapovic products, there may be a lead time of up to 10 working days depending on current stock levels. Our team will inform you promptly if your order falls within this category and provide you with an estimated delivery date.
Tracking Information
Once your order has been dispatched, we will provide you with a tracking number via email. Additionally, the tracking number will be added to your order notes on our website. This allows you to easily track the progress of your delivery and stay informed about its whereabouts until it reaches your doorstep.
International Shipping
We now calculate international shipping costs separately to ensure the most accurate and competitive rates. If you’re placing an order from outside the UK, please contact us for a shipping quote before completing your purchase. Our team will provide you with the best available options tailored to your location.
We are committed to providing you with the best possible delivery service, ensuring that your orders reach you in a timely manner and in pristine condition. If you have any questions or concerns regarding our delivery process, please don't hesitate to contact us for assistance.
For information regarding Returns, please refer to our T&C's.
Email: Store@avontuning.co.uk
Phone: 01454 800 117
Online we currently accept payment from the methods listed above including a wide range of finance options.
Finance Options
In order to get the kit you want, when you need it, without ruining the family finances we offer a highly flexible range of finance options to help you get the best products on your vehicle now rather than at the end of the season when you've saved up the cash to make the purchase. There are even interest free options which effectively spread the cost without costing you any extra.
Avon Tuning Limited is an Introducer Appointed Representative of Social Money Limited t/a Payl8r who is authorised by the FCA under Ref. Number 675283. Credit is subject to creditworthiness and affordability assessments. Missed payments may affect your credit file, future borrowing and incur fees.
What Our Customers Are Saying
Mark W.
“Thanks to James and Marcus at Avon Tuning for arranging and fitting a Quicksilver exhaust to my new Defender V8. Everything went like clockwork and it sounds awesome”
Paris C.
"Would highly recommend Avon Tuning. They're extremely knowledgeable, outstanding customer service - we even had a lovely courtesy car for the few hours they had ours. You're in good hands with Avon Tuning!"
Richard N.
"I’d give 6 stars if they’d let me! Avon Tuning did the most fantastic job. I arranged everything with James at the beginning and he was so helpful, guiding me to the correct exhaust system (Miltek) and a Stage 1 Remap"
Peter B.
"Amazing service from James and the team at Avon Tuning.Fitted a new exhaust system on my Aston Martin Vantage, not only does it sound and look great but it puts smiles per miles for me."
