December 27, 2022

RENNtech Testing for 2023 SRO Season at Sebring Raceway.

RENNtech Motorsports #89 AMG GT4 at Sebring Raceway December, 2022

With the start of the 2023 SRO Pirelli GT4 America and GT America Powered byAWS -season approaching, RENNtech Motorsports Team completed testing with the RENNtech Motorsports MB Gram #89 AMG GT4 at Sebring Raceway on December 16th, 2022.

Drivers Thomas Johnson and Michael Auriemma used the opportunity to get familiar with the performance and handling of the AMG GT4 -machine, while the team was monitoring performance and working on car set up.

Cool conditions prevailed on track early Friday morning causing a few cars to slip off track and cutting the first session short. As the day got warmer and the drivers were dialed-in to the capabilities of the Mercedes-AMG GT4, lap times kept on improving.

“Sebring is a serious test for both drivers and the car. The uneven surface of Sebring Raceway is the ideal place for drivers to get familiar with the vehicle on a track and for the Team to perform a shake-down of the car. Track day testing as a great opportunity for us to see in which direction are we going before the upcoming season.” Said Hartmut Feyhl, RENNtech Motorsports Team Director.

The season opener of the GT America Powered by AWS kicks-off in St. Petersburg, March 3rd, while the SRO Pirelli GT4 America -series will start at Sonoma Raceway, March 30th.

September 20, 2022

30 Years of Power – RENNtech S76R

Powered by a 615 hp, 7.6 -liter M120 V12 engine, the S76R is the most powerful naturally aspirated V12 built by RENNtech and the largest displacement on record for the Mercedes Benz M120.

2022 RENNtech S76R 

Building the perfect W140.

In 1992 RENNtech turned out the first performance versions of the Mercedes-Benz M120 V12 -engine. Bored and stroked to a displacement of 7.4-liters and with up to 585 hp of power, these super engines found their way to the RENNtech SL 74 (R129), CL 74 (C140), and the S 74 (W140) through the 1990's.

Fast forward 30 years and RENNtech is following the same blueprints from an era of naturally aspirated and over-engineered luxury by turning a 1992 600 SEL into a 2022 RENNtech S76R through a complete restoration, re-power and interior re-fit.

1997 RENNtech SL 74 

Power: RENNtech bored and stroked the 6.0-liter V12 to an astounding 7.6 -liters, resulting in the largest M120 V12 -engine to date. With the addition of lightweight pistons, titanium connecting rods, beehive springs and titanium retainers for improved spring rate and lighter mass, AMG performance cams, ported heads, custom built airboxes, larger injectors, and fitted with a MY 96 ME-1 engine management system complete with rebuilt wiring harness and RENNtech ECU Performance Tune, the S76R engine is also the most powerful N/A M120 -engine built by RENNtech.

Rated at 615 hp and 703 lb-ft of torque, the M120 -engine produces 213 hp and 275 lb-ft of torque over the stock 6.0-liter (402 hp / , 80 hp more than the ultra rare AMG 7.3-liter found in the SL 73 AMG, S 73 AMG, and CL 73 AMG, and just shy of the 631 hp Mercedes-Benz CLK GTR super car.

Through an extremely labor intense process, the 1992 600 SEL was upgraded to model year 1996 engine management (ME-1) system to fit an RENNtech upgraded 722.6 electronic 5-speed transmission connected to an OS Giken Limited Slip differential. The combination greatly improves power delivery and drivability beyond what the original 4-speed transmission and differential could offer and handle.

7.6 -liter V12 (M120) 605 hp and 715 lb-ft of torque

The S76R features a bespoke braking system utilizing 402 mm (F) and 360 mm (R) Carbon Ceramic discs with 6-piston front and 4-piston rear AMG brake calipers with custom aluminum hats and brackets is connected to an 2nd generation ABS system. The new brake system weighs nearly 3/4 less than the original system and creates incredible stopping power for the S-Class. The large brakes were fitted inside one-of-a-kind RENNtech Classics forged aluminum wheels measuring 19 x 9 (F) and 19 x 10.5 (R) with 285 wide rear tires for additional traction and grip, while shorter coil-springs and a 2nd generation ADS -system were added to improve the handling qualities.

S76R Carbon Ceramic Brake System with 6-piston calipers and 402 mm front discs.

To improve the exhaust flow equal length stainless steel headers, a full-length stainless steel exhaust system with sport catalytic converters and quad mufflers were added. The system gives the naturally aspirated S76R a powerful yet refined sound, which at wide open throttle sounds race-car aggressive and at low speeds hums a muted tune, barely loud enough to be noticed inside the cabin.

Forged 19 in. aluminum wheels custom made for S76R 

Exterior: On the exterior, the S-Class body received AMG ground effects all around, along with RENNtech designed trunk lip spoiler with 3rd brake light, front splitter, and louvered side moldings. Keeping with a low-key style, the lowered stance, large wheels, and dual tip exhaust, offer clues that the black S76R is more than a stately sedan.

Interior: The original interior was completely overhauled with new seats, diamond stich upholstery, carbon fiber inlays, Alcantara headliner, a leather dash and center console, re-covered leather and carbon steering wheel, shifter, and new carpeting. The original rear bench seat was converted to the four-passenger option featuring individual adjustable rear seats, all interior lights were replaced, and the sound system was replaced by a new smartphone compatible head-unit and re-coned speakers.

Custom made interior for S76R.

Outside of the upgraded parts, the 1992 S-Class was restored in every detail. Bushings and ball joints, door lock and soft close actuators, brake lines, new HVAC ventilation pods, hydraulic suspension accumulators, oil cooler, evaporator, heater core, and other worn parts were replaced to make the S76R as good as brand new.

S76R Badging and RENNtech trunk lip spoiler.

With RENNtech’s engine and performance upgrades, the S76R holds its own among contemporary luxury sedans with 0-60 mph acceleration in the low 5 seconds and enough torque to move the 4800 lb. S-Class easily to the 155 mph mark. The added power gives the S76R a highly responsive feel, resulting in a car that drives much lighter and nimbler than the tank-like 600 SEL. 30 years later the interior ergonomics still feel first class, with large dual-paned windows, sizeable seats, and a vault like ambiance and enough space to seat four individuals in true comfort.

30 years after the first RENNtech M120 powered Mercedes-Benz hit the market, the S76R RENNtech adds a chapter to Merceds-Benz W140 S-Class and M120 -engine history. And for those fortunate enough to commission a dream build of this scale, RENNtech Classics holds the blueprints to make the dream a reality.

1992 600 SEL RENNtech S76R built in 2022.

The powerful yet understated profile of the S76R.

S76R interior with diamond stitched upholstery and carbon fiber trim.

Individual adjustable rear seats of the S76R.

RENNtech stainless steel exhaust tips.

RENNtech S76R carbon fiber trim.

May 10, 2022

The Ultimate Black Series: 1066 HP AMG GT Black Series R3


Loaded with motorsport derived solutions, the 2021 AMG GT Black Series is arguably the most track focused road vehicle from Mercedes-Benz AMG since the (homologated) street version of the CLK GTR in 1998.

Continuing the Black Series legacy from where the 2013 SLS Black Series left off, the AMG GT Black Series satisfies the high demand for track-oriented machines built for Club Racing. Lighter and faster, with wider track width, revised body work, larger grille, integrated air extractors within the hood and front fenders, manually adjustable front splitter, and the massive dual-plane rear wing are derived from AMG’s successes with the GT -chassis in GT3 and GT4 racing. 

Track derived performance and racing heritage: AMG GT 3 and CLK GTR at RENNtech 

In Europe the Black Series is offered with track driving options such as a rollbar, four-point seatbelts for driver and passenger, and a fire extinguisher, upgrades that RENNtech has been quick to introduce to the North American market.

RENNtech’s Roll Bar is made to order at their Head Quarters in Stuart, FL, and can be color matched to the vehicle and fitted with Sabelt or Schroth harnesses. The all new RENNtech Track Series forged high-performance aluminum wheels were designed specifically for the AMG GT -series (C/R 190 chassis) and offer owners a track focused and stylish alternative to the OEM wheels. 

 RENNtech Track Series Forged Wheels in Machine Black.

On the power side, RENNtech’s Hand Held ECU Tuner  instantly produces an additional 99 HP and 95 LB-FT, bumping the AMG GT Black Series up to 843 HP and 739 LB-FT.  If that is not enough, the R3 -upgrade delivers an mind-blowing 1066 HP and 831 LB FT running on 93 octane pump gas, making the AMG GT Black Series RENNtech R3 the most powerful Black Series in the world. 

At the heart of the R3 -upgrade is a set of larger and more capable Turbo’s, a set of Stainless Steel DownpipesBlow Off Valves, and BMC Airfilters for improved exhaust sound and flow. To control the power increase, RENNtech has developed a TCU- tune (Transmission Control Unit) for faster and more firm shifts while increasing the torque capacity of the Mercedes-AMG 7-speed dual clutch transmission. The addition of the Stainless Steel Downpipes and Electronic Valve Module (EVM) improves the sound of the M178 V8, and fills the cabin with a raw and unrestricted sound punctuated with the occasional down-shift crackle. 

Four generations of RENNtech Black Series; AMG GT, SLS, SL, and CLK

Acceleration and throttle response is fast throughout the entire powerband, restricted only by the amount of open road and grip from 335 wide Michelin Pilot Sport Cup 2 R rear tires.

Launching the R3 from a standstill with ESP off and TC settings dialed in, the car rips at the ground like a beast, roaring to 60 mph in 3 seconds or less. Rolling at 75 mph and flooring it, the R3 makes an immediate downshift and whips the tach toward the 7,200 RPM redline without lag. Hold it, and the AMG GT will hit 150 mph in 5th gear before continuing a relentless thrust toward the 219 mph (hypothetical) top speed like a fighter jet.

The result is an AMG GT Black Series where all parts have been improved in the name of driving performance. Under normal driving conditions around town the RENNtech R3 handles easy and is as compliant a GT C or GT R. Push it and the power arrives like artillery fire, heightening all senses and delivering an exceptionally engaging driving experience.

The R3 -upgrade is now available through RENNtech and official dealers across the United States, Europe, and Middle East. 

RENNtech is the leading performance tuner of AMG Black Series. 

RENNtech Roll-Bar for AMG GT -series vehicles.

From Track to Street: 1998 CLK GTR 

SLS Black Series RENNtech R1

April 26, 2022

Introducing RENNtech Track Series Forged Wheels

AMG GT R with RENNtech Track Series 19 x 10" front and 20 x 12" rear wheels with Satin Titanium finish.

RENNtech RTS Forged Aluminum Wheels are the latest addition to a legendary line of RENNtech performance wheels.

It all starts with an idea: The right wheel for the right situation. RENNtech Track Series wheels exemplify RENNtech's philosophy of bringing Motorsports Technology to the Streets and were created to be the perfect wheel for performance and track driving.

RTS in Machine Black
RTS in Satin Titanium

RENNtech's product development team set out to deliver a track-oriented, light weight forged aluminum wheel featuring innovative technology and sophisticated design. Engineered for rigorous track use, RTS wheels are packed with functional design elements for improve structural integrity and maximum weight reduction. The refined design aesthetic follows the current Mercedes-AMG design language with visual cues to pre-merger AMG, making the RTS a perfectly balanced wheel for driving on track and the streets.

Initial Design Concept: Inspired by AMG heritage
Design Development: 3d CAD model
Design Review: 3d printed prototype
Engineering: Finite Element Analysis (FEA)

After confirming the technical viability, several design concepts were explored, refined, and translated into CAD to create the first 3D printed prototypes for visual reviews. From these prototypes, combined with stringent engineering analysis of the CAD models, including Finite Element Analysis (FEA) software validation before the final production version emerges for fitment and real-world testing.

Detail: Rigid Spoke Tracer
Detail: Knurled Bead Seat
Detail: Contrast Machined Logo
Detail: Backpad pocketing weight reduction

Rigid Spoke Tracers were incorporated into the spoke profile for improved structural integrity while reducing the overall weight of the wheel. A Reinforced Inner Rim Flange was integrated to better withstand wheel deflection / deformation under high load situations, resulting in improved driving performance and consistency on track.

Aluminum Wheel Casting vs. Flow Formed vs. Forged

RENNtech has strategically partnered with industry leaders Titan 7 Wheels for development and production of the RTS wheel.

"Titan 7's extensive experience in manufacturing track focused wheels combined with their forging expertise and their complete in-house production gives us a high degree of control in the production process. This way we can deliver a wheel of the highest quality and consistency that RENNtech is known for, and our customers have come to expect." said Hartmut Feyhl, President RENNtech Inc.

Each wheel starts out as a solid cylinder of aircraft grade 6061 aluminum. These cylinders are pressurized with 10,000 tons of pressure to improve the grain structure and overall properties of the aluminum to obtain the wheels initial shape and dimensions. The result is a CNC machine ready forging which features no porosity and a densely organized micro structure for an incredibly strong and lightweight wheel.

AMG E63 with 20' RTS in Satin Titanium
AMG E63 with 20" RTS in Satin Titanium

Launched for AMG GT (190) -series and AMG E63 (213), additional model fitments will follow in the coming months. The wheels are available in two finishes, Machine Black or Satin Titanium, along with two RENNtech Design center caps or OEM MB AMG center caps. The RTS wheels are covered by a lifetime structural warranty, allowing you to enjoy the groundbreaking performance of your Mercedes-AMG with confidence, on track and on the streets. 

2022 AMG GT with RENNtech Track Series 19 x 9.5" front and 20 x 11.5" rear wheels in Satin Titanium.

Center Cap V1 in Machine Black
Center Cap V2 in Machine Black

RTS in Satin Titanium with OEM MB center cap.

March 1, 2022

RENNtech Motorsports on Podium in 2022 SRO Season Opener

Chirs Gumprecht finishes 2022 SRO GT America Sesaon Opener with a 2nd Place in the GT4 class.

Sharing track time with the NTT Indy Car series at the St. Petersburg Grand Prix, RENNtech Motorsports fielded two Mercedes-AMG GT4 racecars on the narrow streets of St. Petersburg, FL.

Chris Gumprecht returned to GT4 racing behind the wheel of the C.G. Racing #79 AMG GT4, and new to the RENNtech Motorsports Team, Custodio Toledo, making his GT4 racing debut in the RENNtech #89 AMG GT4.

Starting P7 in class for Race 1 on Friday, Chris Gumprecht avoided a multi car crash on lap one and moved into P4. Gumprecht was able to hold his position until the eventual race winner, Marko Radisic, in the BMW M4 GT4 made an overly aggressive passing attempt. Taking a hit to the left rear corner, Gumprecht spun around and subsequently lost several positions. After settling back into the race Gumprecht recovered for a P8 finish.

Cutodio Toledo delivered an impressive performance in his sportscar racing debut. Racing in the RENNtech #89 AMG GT4, Toledo was unfazed by the multi car crash while avoiding faster GT3 traffic, settling into the race and consistently improving his lap times, finishing his first GT4 race in P11.

Starting P8 in Race 2 on Saturday, Chris Gumprecht was poised to make up for the mishap in Race 1. With a great start, Gumprecht leaped into P3 by Turn 2 and settled into a great race rhythm. Continuously improving his lap times, Gumprecht set his fastest lap time on Lap 23 of 30 while closing the gap to Derek DeBoer's Porsche Cayman GT4 sitting in P2. With relentless pursuit Gumprecht was able to capitalize on DeBoer's mistake in Turn 1, moving into P2 on Lap 25. Gumprecht defended his position finishing the race behind the safety and claiming his first podium of the 2022 season.

After Friday's successful debut race, Custodio Toledo continued to impress in the second race of the weekend. Starting P12 in GT4, Toledo avoided the starting mayhem in Turn 1, skillfully handling the AMG GT4 through the tight streets of St. Petersburg. Constantly improving on his laptimes, Toledo drove a mistake free race finishing his debut weekend in P11.

RENNtech Motorsports will be back in action at the second round of the SRO - North American season in Sonoma, California, April 15 -17, 2022. Sonoma Raceway will also host the season opener of the highly competitive Pirelli GT4 America season. The race weekend will feature two races in the one-driver 40 minute Sprint style an two races in the two-driver 60 min SprintX class.

Watch all the replays of the SRO North American Season at

For additional race pictures and race info visit:

February 22, 2022

RENNtech Engineering Stratasys F770 3D Printer - First in Florida

RENNtech Engineering
Stratasys F770 3D Printer - First in Florida

RENNtech Engineering has utilized 3D printers to create prototypes, jigs, and parts for over two decades. Our most recent addition to the printer lineup is the Stratasys F770, which is capable of printing large parts over 3 feet in length / width and is the first one of its kind in the State of Florida.

The use of 3D printing helps lowering cost and lead time of production parts though verifying concepts and fitment, and shortens the time-to-market for new products. This allows RENNtech to introduce new products to the market at competitive prices without compromising design, quality or time.

3D printing has always been a great tool for rapid prototyping, but there’s a common problem of build volume being too small. With the F770 is capable of producing large parts in one or two pieces instead of five or six. This will enable us to design, and prototype printed parts we have not attempted before; like hoods, widebody kits, and doors. The upcoming years will be very imaginative and exciting, I cannot wait to see what we come up with. “ – Connor Salley, Engineer RENNtech

The Stratasys F770 uses the highest quality ABS and ASA materials which can be used for large size prototypes or lightweight production pieces. The first production piece from the Stratasys F770 will be the Eurostyle Bumper Plate designed for the C257 CLS -chassis.

Designed in house, the Eurostyle Bumper Plate is designed to eliminate the unsightly American “bumperette”, replacing it with a form-fitting insert for a sleek look. After printing, the part will be test-fitted and then finished in either primer or gloss black before made available for our customers.

Other performance products that benefit from 3D printing at this scale include our carbon fiber Aero products. With prototype Aero parts we can test fit and visually inspect parts designed in CAD before moving to carbon fiber manufacturing, a valuable pre-production feature of 3D printing which benefits the end user – the Mercedes-AMG Performance enthusiast.

Stay Tuned and Power Up!