The design is simple. It relies on 3D printing a replacement bezel for the Mazda Miata’s stock round air vents. This bezel is designed to hold a NeoPixel ring from Adafruit. When built with the optional laser-cut diffuser, the parts have a near-stock look when the LEDs are turned off. It’s a classy, stealthy mod – exactly the sort of thing Miata owners need but never seem to have! (Author Note: don’t be mad, I was once one of you!)
With 24 addressable RGB LEDs, it’s possible to display all kinds of data by turning the LEDs on and off and varying the colors. For example, you could readily build a boost gauge that turns on more LEDs at higher boost pressure. It could then be set up to flash red in the event that you surpass safe thresholds. [ktanner] hasn’t specified any particular microcontroller for the setup — but just about any part you like can be used to drive NeoPixels, after all.
One of the hardest, but sometimes best, things you can do for a project is to walk away. [Jroobi] had spent hundreds of hours crafting the digital dash for his MX5 Miata (video, embedded below) and after spending far too long chasing down I2C bugs, he made the difficult decision to step away for a while. However, as of May 2021, [Jroobi] returned to the project and found a power supply was under-specified and was causing brownouts that resulted in crashes.
All in all, it’s an incredible work of engineering. Everything from the massive codebase that describes all the different states to the tasteful graphic design is masterfully done. The Star-Trek-inspired theme and attention to detail really show in the different modes on the tachometer. The dynamic soft RPM limit based on engine temperature is particularly ingenious.
Under the hood of this custom dash are two Ardunios running the show. The center media console offers more controls with a generous touch screen while the instrument cluster shows most of the data. They talk over I2C to each other and communicate with other parts in the car, such as the RGB cabin lighting and the TEIN electronic suspension dampeners. Fuel and temperature levels come in as voltage levels which can be read via an ADC. The gear position is calculated based on RPMs and speed given the wheel size and the transmission in the vehicle.
The idea of camless automotive engines has been around for a while but so far has been limited to prototypes and hypercars. [Wesley Kagan] has been working on a DIY version for a while, and successfully converted a Mazda Miata to a camless valve system. See the videos after the break.
There have been many R&D projects by car manufacturers to eliminate camshafts in order to achieve independent valve timing, but the technology has only seen commercial use on Koenigsegg hypercars. [Wesley] started this adventure on a cheap single cylinder Harbor Freight engine, and proved the basic concept, so he decided to move up to an actual car. He first sourced a junkyard engine head to convert, and use as a drop-in replacement for the head on the complete project car. An off-the-shelf double-acting pneumatic cylinder is mounted over each valve and connected to the valve stem with a custom adaptor. The double-acting cylinder allows the valve to be both opened and closed with air pressure, but [Wesley] still added the light-weight return spring to keep the valve closed if there is any problem with the pneumatic system.
The controller is an Arduino, and it receives a timing signal from a factory crankshaft and operates the pneumatic solenoid valves via MOSFETs. After mounting the new head and control box into the Miata, it took a couple of days of tuning to get the engine running smoothly. Initial tests were done using the compressor in his garage, but this was replaced with a small compressor and air tank mounted in the Miata’s boot for the driving tests.
Although the pneumatic system works well for short test drives, the compressor is quite noisy and adds a couple of points of failure. [Wesley] is also working on a solenoid actuated system, which would require a lot more current from the battery and alternator, but he believes it’s a better long-term solution compared to compressed air. However, he is still struggling to find solenoids with the required specifications. Continue reading “Deleting The Camshafts From A Miata Engine”→
Carburettors versus electronic fuel injection (EFI); automotive fans above a certain age will be well versed in the differences. While early EFI systems had their failings, the technology brought with it a new standard of reliability and control. By the early 1990s, the vast majority of vehicles were sold with EFI, and carburettors became a thing of the past.
The Mazda Miata was no exception. Shipping in 1989, it featured not only multiport fuel injection, but also a distributorless ignition system. Consisting of two coilpacks in a wasted spark configuration, with computer-controlled timing, the system was quite advanced for its time, especially for a budget sports car.
Despite the Miata’s technological credentials, those in the modified car scene tend to go their own way. A man by the name of Evan happened to be one such individual and decided to do just this — scrapping the EFI system and going with a retro carburetor setup. It was around this point that this I got involved, and mechanical tinkering ensued.