Aim: Build from the ground up a World Time Attack Challenge (WTAC) Racecar from the a 1994 EG Civic Hatchback.
Goal: Place in the top 10 open class at WTAC Open Class 2019
So welcome to what will undoubtably be an adventure and quest largely into the unknown. My background is Mechanical engineering and have spent the last 5 years building and racing cars but never something on this scale.
The Car: Well after much deliberation about which car would be best suited for such an application, and studying the WTAC open class rules, the decision of a hatchback was made and with a 1994 Honda Civic showing up for a tiny $400 with no signs of rust and slightly leaky engine, the purchase of a small yet incredibly slow and smelly car was made.
The Plan:
- Create or Find a CAD template of the car.
- Begin the design of basic aerodynamic features
- Strip the car of anything that will not be required and can sell on
- Finalise the final body shape so production can begin on the 'wide body'
- Create accurate CAD model of the engine bay
- Select an engine, Make a CAD model and design mounts
- Mount the new engine into car and start plumbing it in
- Wire the new engine with the use of a MoTec ECU (Have past experience and a tuner)
- Fit rollcage and seat along with any other internal safety devices
- Finalise Design of Aerodynamics package
- Manufacture the aerodynamics package
- Fit and upgrade the suspension
- Paint the car
- Turn the key and hope it doesn't go boom!
I am sure there will be a lot of smaller, time consuming steps to be completed but they are the major steps from what I can see but plenty to be done.
--- Step One:
Step one was to start to develop a complete CAD model of the car. I spent days searching the Internet looking for a CAD model but none existed, so it was time to make a measuring jig and mark over 300 points on the car to create an accurate CAD model that aerodynamics could start to be modelled upon. If anybody is interested in this CAD model, more than happy to share it around as it took so long to make.
--- Step Two:
The basic design of the aerodynamic package is largely governed by the rules so using the cad model, the extremities of the rules were marked out and using some intuition and past experience, the beginning point of the package was created. It will consist of a front splitter and wing combo, sideskirts, rear wing and a rear diffuser. The main concern was trying to keep the centre of balance in the centre of the car, as a rear biased car would create understeer through the high speed corners and that is not ideal.
The use of NACA and several other types of wings were tested using CFD with the front wing and splitter being tested using quarter car simulations and the rear wing and diffuser being tested using half car simulations. Future iterations will be constantly occurring during the build and the design will forever evolve until manufacturing of the wings and diffuser.
--- Step Three:
Stripping the car and discovering its past. This was fun as I intend to use nothing from the interior other than the dashboard, door cards and steering column so everything was out in a hurry. Still have quite a few parts hovering around the joint so if anyone is looking for that missing part, I might have it. Anyway, the car was stripped and then put up onto jackstands, ready for the exterior to also be stripped and most parts will be custom throughout this build.
The main pieces to keep were the front fenders, the lower hatch and the bonnet. All of these will be modified and recreated using Carbon fibre to limit the weight and also allow the body to 150mm wider to allow for wider tyres and additional shaping for aero. I intend to do a full how to guide on the creation of composite panels so anyone can do it at home.
This is currently where I am at with the build. The front left fender has been shaped and is going through the final stages of sanding. Once I can get access to my computer, I will be looking to upload photos on the progress to date and also elaborate on anything interesting.
This is a long term project and will take considerable time. I am always open to comments and feedback and also giving out any advice if someone my ask.
Updates coming shortly
David
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