My NA Miata project car arrived with significant damage to the Car Front Part. The frame rails ahead of the front struts were compromised, necessitating a complete front-end rebuild. As I progress towards painting and reassembly, constructing a robust and functional car front part is crucial. My approach involves creating a tubular front bumper that integrates with the existing front frame rails and strut mount reinforcements, ensuring structural integrity for this build. The primary goal is to design a car front part that is as compact as possible while providing adequate protection to the wheels and engine compartment.
Front-End Design Considerations for a Track-Focused Car
Before diving into the fabrication of the car front part, I needed to address a crucial measurement and make a significant design decision. I realized I had overlooked measuring the distance between the front frame and the front sway bar, a critical dimension for constructing the sway bar attachments alongside the bumper. To obtain this measurement accurately, I temporarily detached the engine from the front subframe and re-installed the subframe and front suspension onto the chassis. This step allowed for precise measurements and ensured correct placement during the car front part construction.
To elevate the chassis and gain access, I utilized my DIY car lift to easily slide the subframe underneath.
The major design decision I made was to mount the radiator in the rear of the car. This choice was driven by several factors relevant to the performance and aesthetics of this project. Firstly, considering this car is intended for serious track use, a front-mounted radiator would be highly vulnerable without substantial car front part protection. While a protective screen was considered, the idea of minimizing the car front part length to complement the car’s rear profile became increasingly appealing. Secondly, relocating the radiator to the rear would free up the engine bay completely, opening possibilities for future modifications like turbocharging, intercooling, or water injection. Finally, a rear-mounted radiator contributes to better weight distribution by shifting some mass towards the rear and, aesthetically, a rear radiator on an exo-car build presents a unique and aggressive look.
Step-by-Step Fabrication of the Tubular Car Front Part
The fabrication process for this car front part was relatively straightforward. I began by attaching two forward-extending bars to the strut tower reinforcement plates that were previously fabricated. Next, a bar was positioned perpendicularly between these forward bars, aligning just ahead of the sway bar plane. To create the lower section of the car front part, two drop bars were added to bring another horizontal bar into line with the sway bar level. This lower bar was then triangulated to the front bar that spanned across the ends of the initial forward bars. For added strength and rigidity to the car front part, angled bars were run from the forwardmost bar back to the strut reinforcement attachment points on the main roll cage. This configuration resulted in a robust, triangulated front bumper structure, effectively supporting the sway bar load without any noticeable flex.
The forward bars are connected to the reinforcement plates, a step I completed earlier during part 9 of this build.
The newly fabricated tubular front bumper, a key component of the car front part. The foremost bar acts as the bumper itself, and the lower bar is where the sway bar mounts will be attached. The entire structure is triangulated for maximum strength, integrating with the roll cage and frame.
Integrating Sway Bar Bushing Mounts into the Car Front Part
To properly integrate the sway bar mounts into this custom car front part, I fabricated two mounts from 3/16″ steel. These mounts are simple rectangular plates, each drilled with two holes to accommodate the sway bar bushings. Due to limited clearance at the upper hole location, bolts were inserted from the backside and welded in place. The excess bolt material on the back was then ground down to ensure a flush surface before welding the plates to the car front part structure. Finally, these fabricated plates were attached to the sway bar and welded securely to the previously constructed bumper assembly.
The sway bar mount plate starts as a basic rectangle cut from 3/16″ steel. Two holes are then drilled to allow mounting of the bushing bracket.
Before and after welding. To address clearance issues, a bolt is welded into the upper hole of the bracket from the reverse side. The back of the weld is then ground down to approximately 1/16″, maintaining weld strength while minimizing protrusion.
Here, the completed sway bar bracket is shown attached to the lower section of the tubular bumper assembly, now a functional component of the car front part.
Upcoming Fabrication Stages
With the car front part fabrication nearing completion, only a few more steps remain in this phase of the project. I still need to weld a crossbar to the rear section of the roll cage to accommodate the rear-mounted radiator, fabricate and install mounts for the side window nets, and construct the frames for the windows and roof. Once these fabrication tasks are finished, the entire car will be prepped for paint. Following paint, the exciting phase of reassembly can begin, bringing this project closer to its track debut. (I also need to develop a solution for wheel wells to ensure the exo car meets the legal requirements for wheel-to-wheel racing).
This time-lapse captures the moment I cut away the previously constructed front end, making way for the shortened design necessitated by the rear-mount radiator decision, ultimately shaping the final car front part.
