| Weistec Horsepower | 605 |
| Weistec Torque | 624 |
| Manufacturer | Weistec |
| Street legal in all the US States | No |
| Engine Family | M178 |
| Stock Horsepower | 456 |
| See more | |
| year | make | model | trim | engine |
|---|---|---|---|---|
| 2021 | Mercedes-Benz | AMG GT S | Coupe (C190) | Twin Turbo 4L V8 (M178) |
| 2020 | Mercedes-Benz | AMG GT S | Coupe (C190) | Twin Turbo 4L V8 (M178) |
| 2019 | Mercedes-Benz | AMG GT S | Coupe (C190) | Twin Turbo 4L V8 (M178) |
| 2018 | Mercedes-Benz | AMG GT S | Coupe (C190) | Twin Turbo 4L V8 (M178) |
| 2017 | Mercedes-Benz | AMG GT S | Coupe (C190) | Twin Turbo 4L V8 (M178) |
| 2016 | Mercedes-Benz | AMG GT S | Coupe (C190) | Twin Turbo 4L V8 (M178) |
| See more | ||||
Product Description
The M178 is AMG's first clean-sheet V8 built specifically for a single car, the AMG GT, continuing a V8 lineage Mercedes proudly traces all the way back to the legendary 300 SEL 6.8 AMG racer. Like the M156 and M159 before it, every M178 is hand-built in Affalterbach under AMG's "one man, one engine" principle, the builder's own signature stamped onto the engine plate. What truly sets it apart technically is its "hot inside V" layout, which tucks both turbochargers inside the cylinder banks rather than outside them for a more compact, better-breathing package, combined with dry-sump lubrication that lets the 4.0-liter twin-turbo V8 mount low in the GT's chassis for a lower center of gravity and razor-sharp handling balance.
Weistec's ECU tune for the M178 is a software recalibration of the factory engine management, built around the hot-vee turbo layout and dry-sump architecture AMG already engineered. The gain is substantial, 456 to 605 horsepower and 443 to 624 lb-ft of torque from the factory hardware, delivered through an OEM-level calibration process, with knock protection, thermal management, and the GT's factory diagnostics fully preserved. A hand-built masterpiece of an engine, taken to a level even Affalterbach didn't send it out the door with.
How Do You Get Your M178 ECU Tune Tuned?
Follow these steps — this is what your specific vehicle needs and supports.
Choose Your Tune Stage
Core Improvements
Standard with this tuneFree Add Ons
Pick Your Tuning Method

Cypher Plus
Order a Cypher Plus and tune your car yourself from your phone, entirely through the MyFlasher app. Watch how it works.

Mail It In
Remove your ECU or TCU and mail it to us for tuning. Required for some applications.

In Person
Bring your vehicle, or just your ECU/TCU, to our Anaheim, CA headquarters. Call 714-202-0005 or email sales@weistec.com to schedule.

Cypher Pro Dealer
Visit a certified Cypher Pro Dealer near you. Find one with our dealer locator.
Complete The Upgrade
An ECU tune alone won't remove all factory limits or fix how power reaches the ground. Add these to round out the upgrade with no limitations.
Read the full CPC & TCU breakdown →
What is a CPC module?
The CPC (Central Powertrain Control) is a separate control unit that manages things like the active exhaust valves, radiator fan, intercooler pumps, and speed limiter. On many newer Mercedes-Benz vehicles, it also houses torque limiters that can hold back an ECU tune from reaching its full potential.
What is a TCU tune?
A TCU (transmission control unit) tune delivers faster, firmer shifts with higher line pressure, reducing clutch slip and increasing the transmission's torque capacity. It's a worthwhile upgrade on its own, or paired with an ECU tune for a fully sorted powertrain.
Good to Know
- This is a reflash of your original module, not a stand-alone unit.
- Power gains vary by vehicle, modifications, fuel, and operating conditions (ambient temperature, altitude, etc.).
- New or upgraded spark plugs are always recommended when tuning.
- Product may not be emissions compliant. Check local laws prior to installation.
- Always use a battery charger during programming.
Fitment not confirmed
This part is not confirmed to fit your selected vehicle.

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