BenzUnited Parts
Mercedes-Benz M278 Intake Filter Spacer Kit – 4.7L V8 BiTurbo E550, CLS550, S550, SL550
Mercedes-Benz M278 Intake Filter Spacer Kit – 4.7L V8 BiTurbo E550, CLS550, S550, SL550
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Unlock the airflow your 4.7L BiTurbo should have had from the factory. This CNC-machined Intake Filter Spacer Kit for the M278 (4.7L V8 BiTurbo) eliminates a known choke point inside the OEM airbox, improving airflow efficiency, sharpening throttle response, and giving the M278 a noticeably freer, stronger midrange — all while keeping a stock-clean engine bay.
🔥 Key Features for M278 Twin-Turbo V8
- Reduces the factory choke point: Lifts the filter into the optimal flow path, increasing effective inlet area and smoothing turbulence.
- Works with OEM & high-flow filters: Fully compatible with Mercedes paper filters and all performance filter upgrades.
- OEM engine cover compatible: Maintains a completely stock appearance — ideal for sleeper builds and inspection-safe mods.
- CNC-machined aluminum: Heat-stable, corrosion-resistant, and precision-fit for every M278 airbox.
- Optional Cerakote finish: Available in stealth black or custom colors with engraving.
📈 Real-World Benefits on M278 Models
- Quicker turbo spool: Lower restriction means the turbos ramp up sooner and with less effort.
- Smoother, stronger midrange: Exactly where the M278 spends most of its time — daily driving, freeway pulls, and overtakes.
- More headroom when tuned: Helps prevent airflow bottlenecks that show up on tuned 4.7L BiTurbo setups.
- Perfect stealth mod: Hidden inside the airbox — zero visible changes under the hood.
No tune required — fully compatible with stock ECU mapping.
⚡ ECU Tuning — Optimized for Mods
🔬 Why the Spacer Works
The factory M278 airbox has a restriction where the filter seals against the upper lid. At higher airflow levels, this lip becomes a bottleneck, increasing turbulence and reducing effective inlet area. Raising the filter slightly fixes this — improving compressor efficiency, airflow stability, and response under load.
✔️ Compatibility – M278 4.7L BiTurbo V8
Fits all Mercedes-Benz models equipped with the M278 4.7L BiTurbo V8 engine:
| Model | Trim | Years |
|---|---|---|
| E-Class (W212) | E 550 | 2011–2016 |
| CLS-Class (W218) | CLS 550 | 2012–2018 |
| S-Class (W221/W222) | S 550 | 2011–2017 |
| SL-Class (R231) | SL 550 | 2013–2020 |
| CL-Class (C216) | CL 550 | 2011–2014 |
| GL-Class (X166) | GL 450 / GL 550 | 2013–2016 |
| GLS-Class (X166) | GLS 450 / GLS 550 | 2017–2019 |
| ML-Class (W166) | ML 550 | 2012–2015 |
| GLE-Class (W166) | GLE 450 / GLE 550 | 2016–2019 |
Note: Only fits M278 4.7L V8 BiTurbo. Does not fit the M276 3.0L V6 found in some 450 models.
⚡ Turbo Blankets – Heat Shield Upgrade
🧰 Installation & Notes
- Bolt-on: Installs at the airbox/filter interface with no cutting or modifications.
- OEM-style sealing: Maintains proper gasket compression around the filter.
- DIY-friendly: Basic tools, 10–15 minutes per side.
📦 What’s Included
- (2) CNC-machined aluminum intake spacers (left + right)
- Digital installation guide
🏁 Why Trust BenzUnited Performance Parts?
We’ve spent over 12 years testing and tuning various Mercedes-Benz platforms. Our development process is based on real driving, data logging, and long-term ownership.
- Platform expertise: We build upgrades specifically for Mercedes V8 turbo engines — not universal parts.
- No hype, no guesswork: If a mod doesn’t show improvement in throttle response, airflow stability, or real acceleration — we don’t sell it.
- OEM+ philosophy: Stealthy, reversible, reliability-focused upgrades that work in the real world.
