M278 vs M157: Mercedes Twin-Turbo V8 Guide, Differences, Specs & Best Performance
Mercedes-Benz’s twin-turbo V8 era produced two icons: the M278 and the M157. Same architecture, completely different personalities. One silent and understated. The other loud, proud, and unmistakably AMG.
M278 vs M157 – The Engines, Side by Side
M278 – 4.7L V8 biturbo powering 550-class luxury models
M157 – 5.5L AMG biturbo found in 63-series AMG models
M278: Quiet Power, Zero Flash
The M278 4.7L V8 biturbo was the perfect engine for buyers who wanted AMG-level torque without the AMG badge. It powered the E550, CLS550, S550, CL550, and most “550” SUV models. Clean, silent, and brutally fast when tuned—without ever asking for attention.
Models Equipped With the M278
- E550 (W212)
- CLS550 (W218)
- S550 (W221 & early W222)
- CL550 (C216)
- GL/GLS 550 (X166)
- ML/GLE 550 (W166)
Many models previously using the M273 5.5L NA V8 transitioned to the M278, marking the shift toward efficient turbocharged performance.
Tuning Potential
With nothing more than a quality tune, the M278 can unlock up to 300 lb-ft of torque. A stock-looking E550 or CLS550 instantly becomes a torque monster capable of outrunning early AMGs. This engine hides its intentions—until you floor it.
M157: AMG Presence and Twin-Turbo Authority
The M157 5.5L AMG V8 biturbo was the engine that defined the modern AMG era. Launched in 2011 and dominating the 63 lineup by 2013, it combined raw torque with unmistakable soundtrack and road presence.
Models Equipped With the M157
- E63 AMG (W212)
- CLS63 AMG (W218)
- S63 AMG (W221 / early W222)
- CL63 AMG (C216)
- ML/GL/GLE/GLS 63 AMG (W166 & X166)
- G63 AMG (W463 pre-M177)
Where the M278 was subtle, the M157 was unapologetically bold. If you bought an M157 car, you weren’t blending in—you were owning the fastest Mercedes on your street.
Honorable Mention: M273 – The Last NA Mercedes V8
Before turbos took over, the M273 5.5L V8 represented old-school Mercedes engineering: linear power delivery, mechanical simplicity, and big-displacement character. For some buyers, that still matters.
Which Engine Is Right for You?
- Choose M278 if you want quiet, stealthy torque with huge tuning upside.
- Choose M157 if you want maximum performance, sound, and AMG presence.
- Choose M273 if you value NA throttle feel and old-school V8 character.
Each engine represents a different philosophy—but all reward the right upgrades.