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RENNtech ECU+ Upgrade | X253 | GLC63 AMG (S) 4MATIC+ SUV | 601 HP/644LB-FT | 4.0L V8 BiTurbo | M177 | MY2016+

ECU+ Upgrade | GLC 63 AMG S and non-S | Up to 601 HP / 644 LB-FT | Gains: +75 HP & +113 LB-FT
SKU: ECU:54.253X.GLC63BT
Retail price without tax: $3,280.00

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RENNtech HHT (hand held tuner) allows you the unlimited ability to switch between tuned and stock ECU programming and requires no ECU removal!

Our proprietary tuning module stores both the RENNtech tuned file and your vehicles stock file. The module plugs directly into the OBD2 port and delivers the file you choose directly to the ECU. Programming takes only a few minutes and the vehicle can be reflashed at any time as many times as you wish.

RENNtech has been at the forefront of ECU tuning since electronic engine management started to show up in vehicles during the mid 1980s! Our experience, countless hours of in-house research, development and exhaustive testing ensure that our proprietary ECU upgrade offers incredible performance gains and rock solid daily driver reliability.

RENNtech tuning software for Mercedes offers significant gains in horsepower and torque across the vehicle's entire power band. By modifying ignition timing and throttle mapping, optimizing air-to-fuel ratios, increasing the engine's rev limiter and modifying boost mapping for turbo-charged vehicles, RENNtech performance software unleashes the true potential of your Mercedes.


With the proprietary RENNtech ECU Tuning the X253 - GLC63 AMG 4MATIC+ gains up to +75 HP and +113LB-FT, based on power numbers measured by RENNtech. Please note that the Mercedes M177 engine performance when measured, obtains higher numbers than rated from factory. The maximum power number reached with the RENNtech ECU Upgrade for the GLC63 and GLC63 S AMG 4MATIC+ is 601 HP and 644 LB-FT.


50-State Street Legal RENNtech HHT

The HHT for Mercedes-Benz and Mercedes-AMG, 4.0 L BiTurbo V8, M176 | 177 | 178, engines is EPA Emissions compliant and street legal in all 50 States.

This product conforms to EPA Emission Standards and does not reduce effectiveness of your vehicles original pollution control systems.

A CARB Executive Order was granted to the RENNtech HHT based on emission test results in the modified configuration, an examination of the On-Board Diagnostic II (OBD II) system, and an engineering evaluation.

 50 State Logo Tag




  • RENNtech stock power numbers are measured with the GLC 63 AMG. Tune is compatible with GLC 63 AMG and GLC 63 S AMG. Maximum power numbers are for both, S and non-S models.
  • We have found the M177 engine stock performance numbers vary from the baseline figures claimed by Mercedes-Benz. We typically see higher baseline numbers than claimed by the factory.
  • Power gains are calculated based on stock numbers measured by RENNtech. Crank Performance Numbers are calculated with a 16% Drivetrain loss on 4MATIC+ vehicles.
  • Numbers published by MBUSA are an average over a 750rpm range for HP and a 2,750rpm range for TQ. Power gains are calculated based on the peak stock performance measured by RENNtech.
  • Our numbers will be dependent on conditions and fuel quality. 93+ Octane gasoline is mandatory with this Performance Upgrade.
  • 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 Tests:
Vehicle Upgrades 0-60mph 0-100mph 60-130mph 1/4 Mile ET Trap Speed
X253 - GLC63 AMG SUV

Stock w/Launch Control

3.74 sec 9.46 sec 13.26 sec 12.21 sec 112.82 mph
X253 - GLC63 AMG SUV Rt ECU Upgrade w/Launch Control 3.45 sec 8.92 sec 12.36 sec 11.86 sec 115.59 mph
X253 - GLC63 AMG SUV Rt ECU+ Upgrade w/Launch Control 3.25 sec 8.27 sec 12.20 sec 11.67 sec 116.73 mph
*If not otherwise noted, performed on non-prepped asphalt and with OEM, Street-Legal and/or Non-Performance tires. Data measured with Racelogic Performance Box.

Performance Numbers Overview 


GLC63 AMG 4MATIC+ (MY2016+ | X253 | M177 | 4.0L V8 BiTurbo) Stock Performance (at crank):

  • Rated by Mercedes-Benz (avg.):                        469 HP @ 5,500-6,250rpm; 479 LB-FT @ 1,750-4,500rpm
  • Dyno measured by RENNtech (peak):               526 HP @ 6,250rpm; 532 LB-FT @ 4,600rpm
    • Note: Mercedes M177 engine performance when measured on the dyno obtains higher power numbers than rated from factory. Performance numbers published by MBUSA are a calculated average within a specific rpm range, which obviously result  in lower power numbers than at the peak. HP and TQ gains calculated by RENNtech are always based on peak stock results measured by RENNtech and upgraded peak results measured by RENNtech.
    • For transparency and comparability, RENNtech published the average stock power during the rpm range set by MBUSA and the peak stock performance


GLC63 AMG 4MATIC+ (MY2016+ | X253 | M177 | 4.0L V8 BiTurbo)  Modified Performance (at crank):

  • Rated by RENNtech (peak @crank):              601 HP @ 5,500rpm; 645 LB-FT @ 4,600rpm
  • Rated by RENNtech (peak @wheel):              505 whp @ 5,600rpm; 542 wtq @ 4,600rpm
    • Crank Performance Numbers are calculated with a 16% Drivetrain loss on 4MATIC+ vehicles.

For detailed explanation on crank HP, wheel HP, drivetrain loss, etc. please click here.


Dyno-Graph for Performance measured at the wheels:


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: