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RENNtech SLR 74

With the SLR7.4 the target was to deliver an extraordinary car that could run with the fastest sports cars and maintain a low-key appearance around town. The result was the Emerald Green “wolf in sheep clothes” RENNtech SLR7.4. The car was a spare-no-expense build for a customer who already owned two RENNtech cars from before. The car had to meet the high expectations set by the customer and by the bench mark cars of the era; the SL 73 AMG, Viper GTS, and Porsche Turbo. A comfortable convertible that would outperform the fastest sports cars and make daily drives around town without a fuss. Performance, handling, appearance, and reliability had to be perfect and without compromise. To bring out additional power from the M120 we started by increasing the bore to 91 mm and stroke to 95 mm. We added a custom billet crankshaft, titanium connecting rods, and Kolbenschmidt pistons. This resulted in a 7.4 liter displacement giving it the moniker SLR7.4 (The SLR part came from Sport Light RENNtech) New high-lift camshafts were made from Mercedes-Benz blanks and 48 larger, longer, and lighter valves were sourced from the Judd F1 team in England. The engine required additional clearance, so we built a custom hood out of carbon fiber. This reduced weight and allowed us to create louvers for airflow while adding space for the engine manifold. The seats were changed to Recaro’s, and re-upholstered to match the custom dash with carbon-fiber inserts replacing all the original wood trim. A RENNtech stainless steel exhaust and K&N filters were added for optimal exhaust flow and air intake. The original adaptive shocks were replaced with fully adjustable Konis, and higher-rate springs and sway bars were added for stability and handling. To cancel out the “toe-in” we built new suspension links for the rear. For better torque handling and quicker shifting the 4 speed transmission was modified with a new valve body for first gear starts. The brakes were upgraded to a set of vented and slotted rotors with four piston Alcon calipers measuring 14 in. in the front and 12 in. in the rear. When finished, the SLR7.4 weighed 424 lbs. less and had 191 more horsepower than the standard R129 SL600. It has more power and torque than the AMG 73 SL and ran 0-60 mph in 3.8 seconds, at pace with the Ferrari F50. This is a car that can reach 190 mph and make a 17-hour road trip in comfort with the top down. A car that delivers performance without any compromise.


RENNtech M120 

7.4 Liter V12 48 Valve

585 HP / 605 LB FT TQ


Carbon Fiber widened wheel wells and hood designed by RENNtech, creates a unmistakable and powerful look for the R129 SL 74.



Zero to 60 mph: 3.7 sec
Zero to 100 mph: 8.7 
 1/4-mile: 12.1 sec @ 119 mph


RENNtech SLR 7.4

Car and Driver, November 1, 2001

"If ever you see a Metallic Emerald Green Mercedes-Benz SL600 with unusual bodywork, two-piece O-Z wheels, and a green fabric top, do not attempt to race it. "

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