Homebrew ECU Increases Mazda Zoom

A big problem with most modern cars is the sheer number of parts and systems that are not user serviceable. This is a big departure from cars of just decades ago that were designed to be easily worked on by the owner. To that end, [Anthony] aka [fuzzymonkey] has tackled what is normally the hardest thing to work on in modern cars: the Engine Control Unit. (Older posts on this project can be found at [Anthony]’s old project log.)

Every sensor in any modern car is monitored by a computer called the Engine Control Unit (ECU), and the computer is responsible for taking this data and making decisions on how the car should be running. In theory a custom ECU would be able to change any behavior of the car, but in practice this is extremely difficult due to the sheer number of operations required by the computer and the very specific tolerances of a modern engine.

The custom ECU that Anthony has created for his Mazda MX-5 (a Miata for those in North America) is based on the PIC18F46K80 microcontroller, and there are actually two units involved. The first handles time-sensitive operations like monitoring the engine cam position and engine timing, and the other generates a clock signal for the main unit and also monitors things like cooling temperature and controlling idle speed. The two units communicate over SPI.

[Anthony]’s custom ECU is exceptional in that he’s gotten his car running pretty well. There are some kinks, but hopefully he’ll have a product that’s better than the factory ECU by allowing him to change anything from throttle response and engine timing to the air-fuel ratio. There have been a few other attempts to tame the ECU beast in the past, but so far there isn’t much out there.

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Converting a Miata to all-electric

[Henry Herndon] converted a Mazda Miata to an all-electric vehicle. There’s a ton of great information in his archives, as well as a round-up video that we’ve embedded after the break. It’s interesting to see him implement two different types of Nalgene bottles as coolant reservoirs. The polycarbonate on the first shattered on him but the soft plastic replacement seems to have done the trick. The batteries add a lot of weight to the vehicle and he ends up refitting the suspension to compensate. [Henry] registered the vehicle with the state and now has a street legal EV of his own design.

Also worth a look is his post covering the 2009 Wayland Invitational. There as a large collection of electric vehicle conversions at the get together.

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