Budget NB1.6 MX-5 Track Build
NB 1.6 Budget Banger Track Build
Read the full write-up at NB 1.6 Budget Banger Track Build ↗
Budget-build NB1.6 MX-5 track project, now gaining an RX-8 drivetrain
A mechanic documents turning a cheap, abused Copart-auction NB1 1.6 MX-5 into a track car on a tight budget, doing all the work himself including rust repair, brakes, wheels and a standalone ECU. The project has since shifted into transplanting an RX-8 engine and gearbox into the car, with the swap underway but not finished at the latest update.
Specs
As stated in the original write-up.
- Wheels
- 15x7 BMW BBS alloys on the front/rear in place of original 18 inch wheels
- Tyres (front)
- Rain Sport 5 tyres fitted to the front
- Front brakes
- Subaru Impreza 4-pot front calipers with eBay adapter brackets
- Wheel arches
- Firefly Speed Shop over fenders fitted to the rear arches
- Alternator
- Alternator sourced from an NA MX-5 to allow standalone ECU control
- Dash display
- Raspberry Pi and 7 inch touchscreen running TSdash as a digital dashboard
Parts used
Parts named as used in the original write-up, grouped the way the Parts page groups them. Where one of the shops we index lists the same thing for this car, it is shown underneath with a link to the shop.
Suspension & Steering 1
- Caliper adapter brackets
Bought on eBay to mount the Impreza calipers to the MX-5 hubs
Brakes 1
- Subaru Impreza 4-pot front calipers
Rebuilt via a trade supplier and fitted to the front using adapter brackets to upgrade braking for track use
In the shops
Performance Brake Pad Set, Ultimax, replacement for Fosseway 4 pot caliper, EBC ↗Moss Europe (UK)· £38.03 GBP
Subaru Impreza 4WD/ABS Brake Hose Kit ↗Rally Design· £92.38 GBP
BC Racing Coilovers - Subaru Impreza G4 GJ7 ↗Paramount Performance· $1,122.18 USD
Wheels & Tyres 2
- BMW BBS 15x7 alloy wheels
Fitted in place of the original 18 inch wheels for better tyre fitment
In the shops
RPF1 15x7 +35mm Alloy Wheel - Matte Black (Enkei) ↗
Moss Miata· $295.75 USD - Rain Sport 5 tyres
Fitted to the front wheels after the intended Yokohama AD08RS could not be sourced
Body & Trim 1
- Firefly Speed Shop over fenders
Bolt-on fender flares fitted in place of the fabricated E36 arch extensions
Electrical 3
- Speeduino 4.4d ECU
Standalone ECU wired into the car to run the engine on a budget
- NA MX-5 alternator
Fitted to provide alternator control not handled by the aftermarket ECU
- Raspberry Pi digital dashboard with 7 inch touchscreen
Built as a custom display running TSdash, housed in a 3D printed surround
Photos
33 pictures collected from the write-up, in the order they were posted, shown from NB 1.6 Budget Banger Track Build. A picture opens larger here, with the way through to the page it is on.
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How it was done
Starting condition
Bought unseen from a Copart auction for £525, the car was a poverty-spec UK NB1.6 that had been heavily modified and abused: a hanging front bumper, torn ducktail paint, a smoking ignition barrel, huge wheel spacers, cut arches taped together, an unbolted bucket seat and a rotten passenger chassis rail.
Initial repairs
The owner cleaned the ignition switch to stop the smoking, swapped the oversized 18 inch wheels for smaller BMW BBS alloys, welded the torn inner and outer arch skins back together, and cut out and replaced the rotten chassis rail using cheap eBay repair panels, after bypassing a leaking power steering cooler line.
Brakes and arches
To cheaply upgrade braking for track use, Subaru Impreza front calipers were fitted using eBay adapter brackets, with the calipers rebuilt via a trade parts supplier. The homemade E36 arch extensions were later abandoned in favour of bolt-on Firefly Speed Shop over fenders, fitted in about 30 minutes a side.
Electronics and ECU
After passing an MOT, the builder wired in a non-plug-and-play Speeduino ECU with a wideband lambda sensor, sourced an NA alternator to solve alternator control, and built a digital dashboard using a Raspberry Pi, touchscreen and TSdash software with a 3D printed surround.
RX-8 drivetrain swap
The project direction changed to transplanting an RX-8 engine and gearbox into the MX-5. The RX-8 donor's drivetrain was removed, the MX-5 subframe pulled for measuring, and cutting of the subframe begun with a plasma cutter ahead of fabricating mounting plates, with the swap still in progress.
A summary in our own words. The full account, with all its detail, is in the original write-up: read it at NB 1.6 Budget Banger Track Build ↗
Worth knowing
- Wait for repair panels to arrive before cutting out rust, to avoid cutting more than needed
- Fabricated arch extensions can be far harder to remove later than bolt-on options like Firefly over fenders
- A non plug-and-play standalone ECU on an NB needs a separate solution for alternator control