June 26, 2023

The One that Set the Record.

In this edition of RENNtech Performance Blog, we will dive into the performance development and extraordinary achievements of the RT engineering team and the car that broke the RENNtech Dyno record.

In late January we received a call from a customer who acquired a low mile AMG GT63S Edition One. The customer wanted to know about our GT63 (S) and M177 Engine development, and if it was possible to turn his Edition One into a 9 Second ¼ mile car. This had to be achieved without removing any seats or adding nitrous, and the car needed to run on factory Michelin Pilot Sport 4S street tires, and 93 Octane fuel for daily comfort.

Once the project was outlined and approved, development began at RENNtech headquarters in Stuart, Florida. During several weeks of development and testing in various stages, the results showed promise. The increased flow of air proved to be crucial for the M177 to deliver an astounding 1196 crank HP, 1006.96 WHP, and 935lb of TQ running on 100 Oct Gas.

This is the most powerful RENNtech AMG GT63S in the world, and set a new RENNtech power record by being the first vehicle to break the 1000 WHP mark measured on RENNtech’s Dyno. The Dyno has seen some of the fiercest Mercedes-AMG developments over the past decade, but none had spun the 4-wheel Dyno with this much power.

During road testing, under challenging conditions of a hot Florida day with high humidity and density altitude, the Edition One broke the 10 Second ¼ mile barrier, clocking a quarter-mile time of 9.99 seconds on street tires and no prep. This record setting performance makes it one of the fastest 4-door vehicles ever, and the fastest AMG GT63S Edition One (X290) built by RENNtech.

These cars are quite amazing. The amount of power we have been able to unlock from the M177 engine is incredible, and this development proved how strong the engine can be. With the increased airflow from our carbon fiber airboxes and the right tuning, we were able to gain massive power without compromising usability. Combined with the X290 -chassis, what we have developed is a 1000 WHP Mercedes-AMG that is incredibly fast and perfectly suited for daily driving”.  Said Hartmut Feyhl, President, RENNtech.

With its unrivaled capabilities the Edition One is a testament to the expertise and craftsmanship of RENNtech, as well to the passion of the owner who chose to pursue performance without compromise and chose RENNtech for the development.

My objective was to make a unique one- of-a-kind super car that no one else in the world has, and RENNtech was able to deliver. It’s a special car that I can occasionally take out for a night on the town, to a car show, or an occasional spirited drive.” said the Owner  @ed1t1ongt63s 

What sets RENNtech apart from other tuners is their commitment to transparency & verifiability. They publish information that can be substantiated with Dyno charts and videos, ensuring that every claim is backed by tangible evidence. They also go beyond raw power, prioritizing the performance, safety and reliability of their tuned vehicles on the road”. the Owner continued.

While many aspire to redefine automotive boundaries, this rare RENNtech built AMG GT63 Edition One managed to surpass all expectations, with unrivaled performance steeped in Mercedes-Benz AMG luxury and reliability. With its awe-inspiring performance, this unique AMG GT63 S Edition One stands above the rest and has etched its name to a long list of legendary RENNtechbuilds.

*Due to the high degree of development and tuning, power levels that exceed 1000 WHP are only available through RENNtech headquarters in Stuart, FL. 

June 7, 2023

RENNtech Unveils the 1196 HP Limited Edition Mercedes-AMG GT63 4-Door Coupe RIIIx .


RIIIx : The Most Powerful RENNtech Upgrade Ever1196 HP | 871 LB-FT

We are proud to announce the launch of our latest creation based on the Mercedes-AMG GT 63 RIIIx. With superior power and advanced performance tuning, the limited edition RIIIx is set to claim its place at the top among street-legal 4-door vehicles in the world.

The RIIIx is powered by the Mercedes-AMG twin-scroll M177 BiTurbo V8, producing equipped with RENNtech’s Stage II high-performance turbochargers that feature larger inducer and exducer wheels along with a special core assembly featuring reinforced axial bearings for less rolling resistance and zero lag.

To ensure the engine receives the necessary air flow and fuel supply, the GT63 RIIIx is fitted with an integrated carbon fiber air intake system with a 30% larger filter surface, and high-pressure fuel pumps. The exhaust system features RENNtech stainless-steel high-performance downpipes with free-flow 200 cell catalytic converters and upgraded performance mufflers produced specifically for the AMG GT63.

Thanks to RENNtech’s Transmission Control Unit (TCU) and Powertrain (CPC) upgrades, the RIIIx boasts lightning-fast acceleration, achieving 0-60 mph in 2.44 seconds and 0-100 mph in 5.5 seconds and a quarter-mile time under 10 seconds, the RIIIx was built to blow the all the doors off the competition.

Through an extensive series of tests on the Dynamometer, RENNtech Engineering revised ECU mapping for injection, ignition, and boost pressure control  as well as real-world test drives on the road and at the track. 

The peak output of 1196 HP and 927 LB-FT of torque is produced at 6,200 rpm on 100 octane fuel, and 964 HP and 846 LB-FT of torque on 93 octane fuel. The driver can easily switch between octane ratings using the Hand-Held Tuner, offering the option for maximum power and convenience for daily driving.

The RIIIx’s exterior carbon fiber aero package includes functional styling elements to produce more downforce for improved handling and stability at high speeds and the aesthetics of the GT63. These highly refined aero components were designed by RENNtech and are constructed in the USA using aerospace-grade pre-preg carbon fiber. 

With the record braking power figures, RENNtech Engineering has once again demonstrated its commitment to innovation, performance, and design. For a lucky few, the RIIIx is an exceptional vehicle that combines Mercedes-AMG cutting-edge technology and engineering with unparalleled power, making it one of the fastest four-door vehicles on the market.


  • 1196 HP & 927 LB-FT (100 Oct.)
  • 965 HP & 817 LB-FT (93 Oct.)
  • Carbon Fiber Air Boxes
  • Stage II Turbo Upgrade
  • Downpipes with 200 Cell Catalytic Converters
  • Stainless Steel Performance Mufflers
  • ECU Programming
  • Transmission Control Unit programming
  • Powertrain Control Unit programming
  • High Pressure Fuel system
  • Blow Off Valves
  • Hand Held Suspension Module
  • Exhaust Valve Module
  • Heat Exchanger


  • Carbon Fiber Front Splitter and Canards
  • Carbon Fiber Side Skirts
  • Carbon Fiber Rear Diffuser
  • Carbon Fiber Adjustable Rear Wing with Fixed Base
  • RENNtech RIIIX badging


  • RENNtech RPS 10.2 Forged Aluminum Monoblock wheels
  • Front: 21 x 10.0”
  • Rear: 22 x 12.0”
  • Michelin Pilot Sport 4 S
  • Front: 275/35 ZR 21
  • Rear: 335/25 ZR 22

Carbon Fiber Side Skirts and Forged RPS 10.2 Wheels

Carbon Fiber Rear Wing with Fixed Base

Carbon Fiber Front Splitter with Canards

Carbon Fiber Rear Diffuser