The ZC9 represents my dream for Zephal Technologies, the dream of many children to create their own supercar. Thanks to a project carried out at the Université de Technologie de Belfort-Montbéliard, concrete figures have begun to be associated with this vision.

This article is the first in a series of four that will be organised as follows:

1. Ideation and concept
2. Architecture and ergonomic measures
3. Exterior design
4. Interior design

The origins

The images of the ZC9 published in various places on the site were first published in the period 2022-2023. But in reality, the car has been around much longer, since 2011 to be precise. (Children's drawings count!)

In 2016, I created my first 3D model on Google SketchUp, which was still free at the time. It took many long days and nights of creating polygons one by one to give my ZC9 a credible shape, but I was pretty proud of the result.

In the years that followed, I produced a number of drawings with varying degrees of variation. The aim each time is to improve on what already exists to create an ever more credible and realistic car.

Arrival at UTBM

In 2020, I joined the Université de Technologie de Belfort-Montbéliard in the Ergonomics, Design and Mechanical Engineering programme - EDIM for short. This gave me the opportunity to develop the ZC9 by making the most of the subjects I was taught. Drawing, ergonomics lessons, dimensioning... For a drawing project, I decided to make drawings on A3 paper of an improved version of the ZC9, the ZR convertible.

We are then told that there is a specific subject for the end-of-course semester, TO55 personal project. Each student can propose an engineering project which will be assessed and then proposed if it is deemed suitable. In a flash, I propose the ZC9 project to my main teacher. It was an opportunity not to be missed!

There had to be four of us for the project. So I was joined by my classmates Romain Lespine, Pierre Desgrippes and Thomas Chen, with whom we were to make a great leap forward in the design of the car.

Positioning

With the team back together, we were now going to develop a set of specifications and divide up the analysis and benchmarking of the various technical solutions.

First of all, the positioning was defined. The ZC9 will be a ‘medium’ supercar with a mid-engined rear axle, in other words, a competitor to the Lamborghini Huracàn, Ferrari 296 GTB, Mclaren Artura and Porsche 911 Turbo S. It will have a hybrid propulsion system with an internal combustion engine and an electric motor. In all, it should produce around 800 bhp. In terms of character, it will be somewhere between an Audi R8 and a Mclaren 720S: it will be a civilian car, capable of carrying out everyday tasks, but above all it will be a track car.

On a graph with road behaviour ranging from road to race on the x-axis and emotions ranging from technical to dramatic on the y-axis, here's where the ZC9 would fit in.

Benchmarks of technical solutions

In order to obtain a footprint for the various vehicle sub-systems, we carried out benchmarks to choose the best options for our application. Engine, transmission, running gear, electric motor, chassis, etc.

The project was particularly interesting to work on because, although it's an expensive vehicle and therefore gives us a certain amount of freedom in the choice of ‘exotic’ technical solutions, there are always financial constraints that limit our choices, unlike vehicles with no limits, such as the Koenigsegg or Pagani, for example.

Chassis

After making an inventory of the types of chassis available, we selected three potential ones. The others, such as beams, floors, conventional frames, etc., were quickly discarded.

The solutions studied were:

1. Carbon monocoque chassis: This type of chassis offers the best performance for the least weight. However, a monocoque implies costly development and reduced versatility (only one body available or a convertible roof but no major modifications to the structure).
2. Carbon ‘MonoCell’ chassis: Connected to the monocoque chassis, the monocoque part only includes the passenger compartment in a small version (without roof) or a complete cell. Subframes are attached, usually in aluminium.
3. Tubular chassis: Chassis made up of welded tubes, mainly used in ‘home-made’ cars and competition models. This is the easiest type of chassis to build, but also the least expensive. It is also heavier.

We opted for the ‘MonoCell’ carbon chassis in a punter version. The carbon centre section makes the car lighter and allows several body configurations, while being more rigid than the tubular chassis. It would also be cheaper to produce.

Rolling stock

For the running gear, the double wishbone axle was adopted, offering superior dynamic characteristics and more precise adjustments than the other solutions.

Engine & Transmission

Several powertrains were considered at the outset of this project, but our choice quickly fell on a hybrid powertrain with an internal combustion engine in a central rear position and a parallel electric motor on the front axle.

For the internal combustion engine, we were looking for an engine developing around 500hp and capable of running at high speeds. It had to be between 6 and 12 cylinders.

The engines closest to our ideal solution were the V8 from the Ferrari 458 Italia, the V10 from the Lamborghini Huracàn EVO and the flat 6 from the Porsche Cayman GT4 RS. Finally, we used a Ferrari 3.2L V8 from a Maserati 3200GT with 2 turbochargers supplied by Sbarro. This choice was made because it was the engine with the most detailed CAD available to us. It was coupled with an Audi 5-speed manual gearbox, which served as the basis for our modelling.

The engine and gearbox will in future be replaced by an in-house naturally-aspirated 4.6-litre V10 and a 7- or 8-speed dual-clutch gearbox.

Electric propulsion system

In order to guarantee good traction and stability, we wanted to integrate power transmission to all four wheels. However, all-wheel drive is heavy: in the case of a Lamborghini Huracán, for example, the EVO four-wheel drive version weighs 1520 kg, while the EVO RWD two-wheel drive version weighs 1389 kg. That's a difference of 131 kg.

If you're going to add mass, you might as well add power. The electric supplement seemed appropriate. It provides extra power and significant torque from 0 rpm, for improved acceleration compared with a single internal combustion engine. What's more, it allows emission-free driving over short distances, which is practical for everyday journeys.

From a selection of existing engines, those with interesting characteristics were grouped together in a benchmark. The result was that the Tesla Small Drive Unit was the most interesting, offering the best compromise between mass, power and size.

Choice of batteries

Here again, Tesla technology has been chosen. The ZC9 packs two Tesla 6s86p modules of 6.4 kWh, giving a total capacity of 12.8 kWh. Given that the average consumption of a car is 15 kWh/100km, we can expect an all-electric range of around 80km, which is sufficient for most daily journeys.

For the charger, the BMS (Battery Management System) and the plug, we took a Stealth EV 6.6kW 400V, an Orion BMS2 and a CCS Combo 2 respectively.

The electric drive weighed a total of 154 kg, to which must be added the weight of the fixings and wiring. This system weighs just a few dozen kilos more than an all-wheel drive system, while providing 300 bhp and 330 Nm more power for clean daily use.

Later, thanks to the development of axial-flow motors, a BeyondMotors AXM3 or equivalent will be integrated in place of the Tesla Small Drive Unit. Lighter and more compact, it weighs just 27kg and delivers 300hp.

Technical solutions and comparison with the competition

Blueprints chosen for the bodywork

Using the 2016 Sketchup model, we created blueprints by slightly altering the style of the rear of the car, which would serve as the basis for the design of the bodywork. The bodywork will first be designed using CATIA's surface tool, then reworked in depth using Alias Autostudio.

In the next article, you'll discover the secrets of designing the 3D model itself and its sub-systems. See you next week!