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RENNtech Stage II Turbo Upgrade | C190 | AMG GT C | 761HP/632LB-FT | 4.0L V8 BiTurbo | M178 | MY2018+

Includes Turbo Upgrade, ECU Upgrade, and TCU upgrade: Up to +186HP | +111LB-FT
SKU: PKG.09.178.2012
Retail price without tax: $16,880.00

The Mercedes GT is the second Mercedes Benz vehicle fully developed by AMG, the company’s Affalterbach based performance division and long fabled engine builder. The resulting vehicle is nothing short of spectacular and the 4.0L V8 BiTurbo engine within is an incredible platform to build performance upon. 

RENNtech lightweight forged billet turbo wheels feature a dramatically larger than stock impeller (inlet side) and an increase in the turbine trim (exhaust side). This combination of high quality, light weight components compensates for turbo lag despite being a functionally larger turbo. The cartridge supporting shaft is also both larger and stronger designed to handle the larger wheels and additional power. This entire cartridge is then fine balanced as a complete assembly to compensate for these increases. The impeller and turbine housings are then precision CNC machined and flow tested in-house to fit the larger internal cartridge. The end result is nothing short of spectacular with the RENNtech turbo package gaining up to +186 hp and +111 lb-ft.

More power isn’t the only performance benefit as our turbos spool quicker, offer a more responsive throttle and immediate power delivery thanks to a reduction in exhaust back pressure, rolling resistance, higher RPM's and a lighter rotating mass. In addition, our turbo upgrade kit functions with the OEM oil and coolant lines. This isn’t just an OEM turbo charger with machined internals; but a dramatically larger, more powerful turbocharger that blows away anything else on the market!

The RENNtech performance turbo upgrade is truly the ultimate upgrade for your AMG GT C.


Key Features:

  • The RENNtech Stage II Turbo Upgrade
  • Larger impeller (inlet) and turbine (exhaust) cartridge
  • Cartridge shaft is larger and stronger to support larger wheels
  • Entire cartridge is fine balanced as an assembly
  • Lightweight forged billet wheels
  • Less rolling resistance offers quicker spooling
  • Virtually no lag with impressive throttle response
  • Precision machined impeller and turbine housings
  • Up to 761 HP and 632 LB-FT @ crank


It is our recommendation that customers installing the RENNtech Stage II Turbo Upgrade also install the RENNtech Transmission Control Unit (TCU) upgrade for AMG GT R. The TCU upgrade is designed to handle the increased power in a safe and efficient way, maximizing the delivery of power and torque through the 7-speed AMG Speedshift Dual Clutch transmission. Please ask a representative about this option prior to purchasing or installing the Stage II Turbo Upgrade.

About: Transmission Control Unit (TCU)
 -upgrade is engineered for faster and more firm shifts while increasing the torque capacity of the AMG SPEEDSHIFT DCT 7G transmission. RENNtech TCU upgrade is optimized for faster acceleration by matching the power output of our ECU and Turbo upgrades. 

  • Increased Clutch Torque Limits
  • Increased Clutch Pressure
  • Optimized WOT and Part Throttle maps
  • Faster shift times



  • This Turbo Upgrade requires an additional core charge, which will be credited upon return of OEM turbo core to RENNtech
  • We have found the new M178 engine stock performance numbers vary from the baseline figures claimed by Mercedes Benz. We typically see higher baseline numbers than claimed by the factory. Numbers will be dependent on conditions and fuel quality.
  • Power gains are calculated with stock numbers measured by RENNtech
  • To reach the maximum power level, RENNtech downpipes, BOV adapters and high-flow air filters are required.
  • Our numbers will be dependend on conditions and fuel quality. 93+ Octane gasoline is mandatory with this Performance Package.
  • States known for poor fuel quality have to be supplied with a lower power setup. Please call for details and Race fuel options +1-561-845-7888.


Performance Numbers Overview 


AMG GT C (MY2018+ | C190 | M178 | 4.0L V8 BiTurbo) Stock Performance (at crank):

  • Rated by Mercedes-Benz:      550 HP @ 6,250rpm; 502 LB-FT @ 1,750-4,750rpm
  • Rated by RENNtech:               575 HP @ 6,250rpm; 521 LB-FT @ 3,850-5,400rpm
    • Note: Mercedes M157 engine performance when measured, obtains higher power numbers than rated from factory.



AMG GT C (C190 | M178 | 4.0L V8 BiTurbo) Modified Performance (at crank):

  • Rated by RENNtech:              761 HP @ 6,800rpm; 632 LB-FT @ 5,600rpm
  •                                                     670 whp @ 6,800rpm; 556 wtq @ 5,600rpm
    • Crank Performance Numbers are calculated with a 12% Drivetrain loss on the AMG GT.


Contact us

7825 SW Ellipse Way, Stuart, FL 34997
(+1) 561 - 845 7888
Mon - Fri 9am - 6pm


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7825 SW Ellipse Way - Stuart, FL 34997
TEL: 561.845.7888 FAX: 561.845.6777 E-MAIL: