Description
BMW 335i 3.5" Resonated Midpipe (ARM Motorsports)
The ARM Motorsports BMW 335i 3.5" Resonated Midpipe is a performance-focused exhaust upgrade engineered to significantly improve exhaust flow, throttle response, and sound quality on N54 and N55-powered BMW 335i models. This system replaces the restrictive factory dual midpipe assembly with a high-flow, single 3.5" design, delivering measurable performance gains while maintaining OEM-level drivability and fitment.
From the factory, the BMW 335i utilizes a dual midpipe configuration that incorporates secondary catalytic converters. While effective for noise suppression and emissions compliance, this design introduces unnecessary restriction as power levels increase, limiting exhaust efficiency and muting the true character of the engine. The ARM 3.5" Resonated Midpipe eliminates these bottlenecks by merging exhaust flow into a single, smooth-transition 3.5" midpipe, reducing backpressure and allowing the turbocharged engine to breathe more freely.
Designed to bolt directly to the factory axle-back exhaust, the ARM midpipe fully retains OEM exhaust valve functionality. This means quiet, refined operation during normal driving and cruising, while delivering a deeper, more aggressive exhaust note under throttle. OEM comfort is preserved, but performance and sound are noticeably enhanced.
To ensure optimal sound quality, ARM integrates a carefully engineered resonator into the single midpipe section. The resonator is precisely sized and positioned to minimize rasp and harsh, high-frequency tones commonly associated with straight-through exhaust designs—especially on N54 and N55 platforms. The result is a smooth, controlled, and deep exhaust tone that remains aggressive without excessive drone.
Construction & Fitment
The ARM 335i 3.5" Resonated Midpipe begins with a dual 2-bolt flange inlet, allowing it to bolt directly to any downpipes designed to mate to the OEM 335i midpipe configuration. This includes factory downpipes as well as most aftermarket options that retain the OEM-style 2-bolt outlets.
From the inlet, the system transitions seamlessly into the 3.5" single midpipe section, where the resonator enhances tone while maintaining unrestricted flow. Toward the rear, the midpipe splits back into a dual configuration to connect perfectly with the OEM axle-back exhaust. This design ensures proper exhaust flow distribution, correct operation of the factory exhaust valves, and OEM-level alignment.
To accommodate the larger 3.5" piping while retaining the factory chassis brace, the kit includes precision-machined aluminum chassis brace spacers. These spacers provide the necessary clearance for the midpipe to pass through without contact, vibration, or modification. Installation remains clean and fully reversible, with no cutting or permanent changes required.
Vehicle Compatibility
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BMW E90 335i – N54 3.0L
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BMW E90 335i – N55 3.0L
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BMW E92 335i – N54 3.0L
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BMW E92 335i – N55 3.0L
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BMW E92 335is – N54 3.0L
