Inspired by the winged, unlimited-class rally cars from the famed Pikes Peak Hill Climb, RENNtech set about creating a GLK that could master the pack by leaving the rest chewing gravel. But, this wild GLK carries a few surprises beneath its menacing exterior.
Hybrid powertrains are generally connected with fuel efficiency and lower emissions. RENNtech is taking one more advantage of the hybrid principle to make the GLK into a formidable performer, however. By combining an electric motor in parallel with the 3.5 litre V6 petrol engine, RENNtech has been capable of capture the impressive torque that characterises electric motor drives, adding 54 Nm to boost the GLK’s performance off-the-line and away from corners. Using a hybrid drive within a hill climb setting provides the added good thing about maintaining thrust at higher altitudes, when internal combustion engines – which rely on ambient air – start to wheeze.
The specialist Mercedes tuning company has also worked its magic on the base 3.5 litre V6 unit, using components from the latest Mercedes-Benz high-performance 3.5 litre V6 Sport engine. Included in this are a special intake manifold, cylinder and cams heads, that RENNtech has added its very own long-tube headers, composite air intake and RENNtech ECU software. Engine output is perfectly up to approximately 350 hp, augmented further by the electric motor in the hybrid drive.
The additional 72 volt drive is run by 12 volt plug-in batteries. RENNtech is currently taking care of a nickel-hydride solution with regenerative charging for additional range.
“The GLK Rally Racer Hybrid can be a fully-functioning test bed,” explains Hartmut Feyhl, President and founder of RENNtech. “We will use this vehicle being a proof-of-concept, which we will develop and enhance throughout the coming year.”
“With the Rally Racer, we certainly have really increased the car’s performance,” continues Feyhl. “Together with all the more aggressive, sporting look, we have made a powerful and exciting package.”
It is also worth noting that, despite the performance enhancements, RENNtech has succeeded in increasing the fuel economy of the Rally Racer compared with the original version, “proving that high performance and efficiency can coexist,” adds Feyhl.
Bearing in mind that the Rally Racer is built for speed on tough terrain, RENNtech opted to forego creature comforts, cutting the extra weight of the standard GLK by removing many of the sound insulation and replacing the Mercedes-Benz seats with lightweight carbon-fibre buckets. Engineers also fitted a full roll cage and moved several components to the rear in the vehicle to make an almost perfect 50: 50 front/rear weight distribution for improved handling on tight, demanding rally stages.
Another significant handling modification arises from the custom coil-over suspension. Made to RENNtech specifications by suspension supplier KW, the package enables adjustments in height, rake, damping rate, camber and toe-in.
Extra stopping power is provided for the Rally Racer courtesy of an in-house RENNtech brake combo featuring massive 412mm, 2-piece rotors with 8-piston callipers at the front, and 356mm discs grabbed by 4-pot callipers at the rear.
Lightweight 20 inch 3-piece, 5-spoke RENNtech wheels within a “Sniper Gray” anthracite finish, clad in NT05 275/40 20 Nitto rubber at the front and NT05 315/35 20 at the rear, fill the prominent wheel flares that underscore this GLK’s performance potential.
Although extensive exterior revisions were made to accommodate the larger wheels and brakes as well as to widen the track, the main objective of bodyshell modifications was enhanced aerodynamic efficiency. RENNtech used the latest in Computational Fluid Dynamics (CFD) software to develop the package. The front side splitter, rear diffuser and minimize side skirts help direct airflow under the GLK Rally Racer to lower drag and provide added downforce, while improving high speed stability at the rear. The rear wing elements also serve an essential aerodynamic purpose and add emphasis to the aggressive edginess of the original GLK design. From a visual perspective, RENNtech engineers successfully melded their aerodynamic modifications with the flared wheel arches to create a powerful side line that highlights the dynamic thrust of your Rally Racer.
“The GLK was a great starting point for this particular project,” says Hartmut Feyhl, “It has excellent underpinnings for performance tuning and I think the general look really suits it.”
“The GLK gave us a great deal of scope for bringing together form and function. For the RENNtech GLK, performance may have been the main goal, additionally it looks the part,” he adds.