As a long-time enthusiast of Group C racing and particularly the iconic cars from Mercedes-Benz, Nissan, and Jaguar, owning a model that captures that era has always been a goal. Recently, with the re-release of the Mercedes-Benz C11 1990 Group C RC car, that became a reality. While the stock model is enjoyable, I saw room for improvement, specifically in enhancing its chassis for better performance and setup versatility. This article details the journey of upgrading my Mercedes-Benz C11, moving beyond its limitations to create a more tunable and responsive RC racing machine.
The original Mercedes-Benz C11 chassis, while incorporating a bathtub-style mid-section with pan car elements, presents some restrictions. The most notable downsides are the limited setup options and the asymmetrical steering design. To address these, I decided to undertake a comprehensive chassis upgrade with the following key objectives:
- Integrate the robust alloy rear end and axle from a Tamiya F104.
- Implement side dampers for improved handling.
- Achieve symmetrical steering turnbuckles for balanced control.
- Enable independent setup of the center damper, isolating it from the T-Bar to fine-tune roll and damping characteristics separately.
To realize these upgrades for the Mercedes-Benz C11, several custom parts were required. This involved designing and machining a new lower front chassis plate to accommodate servo repositioning, a redesigned T-Bar, and custom mounts for the side dampers.
Relocating the servo to achieve symmetrical steering meant that the shortest wheelbase setting could no longer be utilized, at least with a standard low-profile servo. However, this modification unlocked a range of enhanced setup possibilities for the Mercedes-Benz C11, including:
- Precise adjustment of the center damper’s spring rate.
- Droop setup adjustments for optimized suspension travel.
- Rear ride height adjustments using Tamiya F104 bushings.
- Fine-tuning of side damping for cornering stability.
- Roll stiffness adjustment via the T-Bar front part screw.
All custom components were meticulously machined from high-quality 2.5mm and 1.5mm carbon fiber. For the T-Bar’s front section, I developed two versions: a softer FRP variant and a stiffer carbon fiber option, allowing for further chassis flex tuning. The small upper FRP part at the front was also upgraded to a 1.5mm carbon fiber piece for increased rigidity.
Here’s a view of the Mercedes-Benz C11 chassis underside, showcasing the new front chassis plate and the split T-Bar configuration:
A closer inspection of the rear assembly reveals the integration of the Tamiya F104 alloy rear end and the meticulously crafted mounts for the side dampers:
Moving to the front, this detailed shot highlights the new front end configuration of the Mercedes-Benz C11:
The repositioned servo, now paired with symmetrical steering turnbuckles of equal length, is clearly visible in this top-down view, ensuring balanced and precise steering response for the Mercedes-Benz C11:
And finally, this image provides a clear view of the side dampers, including both the inner and outer mounting points, showcasing the Serpent F110 SF4 formula car spare parts utilized for this upgrade:
The side dampers themselves are sourced as spare parts from a Serpent F110 SF4 formula car. The center damper is the reliable TRF Damper for the F103, complementing the alloy and fiber-reinforced rear components and axle. For the front, fiber-reinforced wheel hubs were also incorporated. To accommodate larger ball cups for enhanced steering precision, ball heads from a Tamiya DT-02 (part number 9804154) were used, a modification inspired by other Group C projects.
The initial track test of the upgraded Mercedes-Benz C11 took place on an indoor carpet circuit. Equipped with a Hobbywing 21.5 G3R motor and a Hobbywing Xerun X10 Handout Spec ESC, the car’s performance was immediately impressive. Even the relatively simple front suspension setup performed admirably right from the start.
However, future plans include upgrading the front suspension to a more advanced design for even greater handling refinement.
A remaining question is whether using a more powerful 13.5T motor would still provide sufficient run time for extended races. If so, this chassis would be ideally suited for Pro 10 race events, where 13.5 blinky setups are prevalent. Exploring higher-capacity LiPo stick packs, around 6000mAh, with appropriate C-ratings might be necessary. Any recommendations on where to find such batteries would be greatly appreciated.
Parts List for the Mercedes-Benz C11 Chassis Upgrade:
- 1x Custom made 1.5mm carbon motor pod
- 1x Custom made 1.5mm FRP or carbon T-Bar
- 1x Custom made 2.5mm carbon front lower plate
- 1x Custom made 1.5mm carbon front upper plate
- 1x Custom made 2.5mm carbon outer damper mounts
- 1x Custom made 2.5mm carbon inner damper mount
- 1x Custom made TPU Bumper
- 1x Tamiya 54166 – Aluminum motor mount F104
- 1x Tamiya 84173 – Steel Axle
- 1x Tamiya 3450157 – Spacer rear axle
- 1x Tamiya 54158 – F104 Aluminum Diff Housing
- 1x Tamiya 54215 – Spur gear adapter
- 1x Tamiya 54330 – Carbon reinforced c-parts (motor mount parts only)
- 1x Tamiya 50591 – ball collar (center damper front mount)
- 1x Tamiya 53901 – TRF Special Damper
- 1x Tamiya 3450707 – Rear Hinge Cover
- 1x Tamiya 3450705 – Rear Hinge A
- 1x Tamiya 3450706 – Rear Hinge B
- 1x Tamiya 9804360 – Shaft
- 1x Tamiya 9804889 – Flanged Tube
- 1x Tamiya 9805777 – Screw
- 1x Tamiya 54154 – Carbon reinforce front uprights (optional)
- 1x Serpent 411360 – Side tubes
- 2x Tamiya 9804154 – Ball connector 5mm
- 1x Fenix G56-1345 – Steering turnbuckles 200mm
- Various M3 screws
- 5mm Ball connectors and ball cups for steering and side tubes
This detailed upgrade transforms the Mercedes-Benz C11 into a highly tunable and competitive RC car, ready for serious track action.
