MadJak's Time Attack Build

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madjak
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MadJak's Time Attack Build

Postby madjak » 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.

Image

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!

Image

Cutting away the excess we are left with just an outer skin.

Image

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.

Image

Updates from here will be slow but I'll update the thread as progress is made.
NA8: N/A 200whp | Haltech | Skunk2 Intake | S90 TB | RCP | 5 speed c/r dogbox | 4.78 diff | AST Shocks
Barbs L: 64.12 | S: 58.62 | Collie: 49.72

GR124
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Re: MadJak's Time Attack Build

Postby GR124 » Fri Jun 09, 2017 2:01 pm

LIKE,,,I'll be following this one

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StanTheMan
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Re: MadJak's Time Attack Build

Postby StanTheMan » Fri Jun 09, 2017 2:52 pm

ohhhh wow :shock: 8) 8) 8)
Satans Ride called F33nix the resurrected NA6

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bruce
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Re: MadJak's Time Attack Build

Postby bruce » Fri Jun 09, 2017 3:57 pm

GOLLY...

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lightyear
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Re: MadJak's Time Attack Build

Postby lightyear » Fri Jun 09, 2017 9:22 pm

You could have just moulded the body. Then you are using nothing of an original shell. Like these guys did on the 86.

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madjak
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Re: MadJak's Time Attack Build

Postby madjak » Fri Jun 09, 2017 10:57 pm

The metal shell is actually very light once you cut it back. I'm not sure you would see much savings in weight with a fibreglass body. Maybe a carbon fibre one would be lighter but then the cost and time benefit isn't there. I'd only do it if I wanted to flares the guards or other major body work.

Also if you damage it it's hard and time consuming to repair. For $100 you can pick up a whole new metal body.
NA8: N/A 200whp | Haltech | Skunk2 Intake | S90 TB | RCP | 5 speed c/r dogbox | 4.78 diff | AST Shocks
Barbs L: 64.12 | S: 58.62 | Collie: 49.72

3gress
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Re: MadJak's Time Attack Build

Postby 3gress » Fri Jun 09, 2017 11:58 pm

Most keen to see the supercharged build. Can i assume a waste gate tempered rotrex design as discussed in previous threads?

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smy0003
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Re: MadJak's Time Attack Build

Postby smy0003 » Sat Jun 10, 2017 8:56 am

Goodness Groceries.
I think everyone will be following this one closely.
[b]Then: Sunlight Silver NB8B
Now: Chaste White NA8

SnaveSnavely
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Re: MadJak's Time Attack Build

Postby SnaveSnavely » Sat Jun 10, 2017 1:08 pm

YES


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lucmor444
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Re: MadJak's Time Attack Build

Postby lucmor444 » Sat Jun 10, 2017 2:52 pm

Impressive - and what a pristine work space you have available!

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Re: MadJak's Time Attack Build

Postby NitroDann » Sat Jun 10, 2017 7:58 pm

Well ƒü¢k..


Ahh, amazing effort.
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speed wrote:If I was to do it again, I wouldn't even consider the supercharger.

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Re: MadJak's Time Attack Build

Postby project.r.racing » Sat Jun 10, 2017 8:06 pm

Nice White Morris

speed
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Re: MadJak's Time Attack Build

Postby speed » Tue Jun 13, 2017 9:14 am

This will be epic.
Have always respected and admired your approach to mods.
I'm excited for you :)

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madjak
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Re: MadJak's Time Attack Build

Postby madjak » Thu Jun 15, 2017 5:55 pm

yeah it's a nice workshop... This car is housed at my brother's house as my dad's workshop is full.

The design of the spaceframe is taking a while as I needed to source a couple of subframes for layout purposes. The subframes will be replaced with the main truss structures which makes it all more rigid, but a whole stack more complex.

here is our first pass, getting suspension points picked up etc. The actual main hoop and top bars are all just placeholders atm.

Image

I've also been busy with my pneumatic sequential H-pattern shifter which is a whole massive undertaking in itself. Progress on this car will be slow.
NA8: N/A 200whp | Haltech | Skunk2 Intake | S90 TB | RCP | 5 speed c/r dogbox | 4.78 diff | AST Shocks
Barbs L: 64.12 | S: 58.62 | Collie: 49.72

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Re: MadJak's Time Attack Build

Postby mrpham » Mon Jul 31, 2017 8:24 pm

Subscribed!
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