MadJak's Time Attack Build
Posted: Fri Jun 09, 2017 1:39 pm
Time for a new build thread... I'm starting a new project car, this time from scratch and like everything I do as much DIY as possible. The goal is to make a super lightweight MX5 one the cheap with a target weight of around 700kgs specifically built for time attack and sprints. It will look and function like my existing MX5 except it will be built around a space frame chassis. Initially it will run my 1.8l N/A engine, but later will get supercharged with a power range of around 450 whp. To balance that power it will run an epic 3D printed rear wing, rear diffuser, flat floor and large front splitter.
Time wise this is going to take a while. Building a complete spaceframe car will take lots of hours and between all my other projects I'm estimating at least 1 year until it's ready.
The starting point was a nice straight chassis I picked up from fellow MX5 enthusiast. We set to work cutting off the outer skin of the body, which will be the only part kept. The chassis and subframes will be rebuilt as a full tubular space frame / cage. To cut the body from the chassis took around 50 cut off discs and around 6 hours of work. That's adding lots of lightness there!
Cutting away the excess we are left with just an outer skin.
Because we are rebuilding everything about the car, we can change the location of some things. I'm thinking we'll bring the engine back a bit, probably 150-200mm, maybe bump it over to the passenger side slightly. We're also going to drop the entire body 50mm in relation to the running gear so that the body looks low and wide. The drivers seat will move back as far as the hardtop / cage will allow and in towards the centre as far as practical for safety.
The subframes will be removed entirely as the space will be used to place the space frame truss which will be more rigid and lighter.
Here is my quick mock up. The cage design needs lots of work and will be run through some FEA programs to test for rigidity and weak points.
Updates from here will be slow but I'll update the thread as progress is made.
Time wise this is going to take a while. Building a complete spaceframe car will take lots of hours and between all my other projects I'm estimating at least 1 year until it's ready.
The starting point was a nice straight chassis I picked up from fellow MX5 enthusiast. We set to work cutting off the outer skin of the body, which will be the only part kept. The chassis and subframes will be rebuilt as a full tubular space frame / cage. To cut the body from the chassis took around 50 cut off discs and around 6 hours of work. That's adding lots of lightness there!
Cutting away the excess we are left with just an outer skin.
Because we are rebuilding everything about the car, we can change the location of some things. I'm thinking we'll bring the engine back a bit, probably 150-200mm, maybe bump it over to the passenger side slightly. We're also going to drop the entire body 50mm in relation to the running gear so that the body looks low and wide. The drivers seat will move back as far as the hardtop / cage will allow and in towards the centre as far as practical for safety.
The subframes will be removed entirely as the space will be used to place the space frame truss which will be more rigid and lighter.
Here is my quick mock up. The cage design needs lots of work and will be run through some FEA programs to test for rigidity and weak points.
Updates from here will be slow but I'll update the thread as progress is made.
