MegaSquirt Install and Remap on a Mazda Eunos
Eunos was a marque of the Japanese car manufacturer Mazda, it was marketed as its upscale, fun to drive line in its home market. The brand existed from 1989 to 1996. The name was derived for the ancient Greek “eu” meaning “good” and “nos”, an abbreviation of “numbers” in English, meant to signify a number, or assortment, of good things. The Marque was launched in Japan with the Eunos 500 in January, 1992 and many of the vehicles created were exported to other markets.
The Mazda MX-5, released as the Mazda MX-5 Miata in North America and as the Eunos Roadster in Japan, is a lightweight two-seater roadster with a front-engine, rear-wheel-drive layout. Manufactured by Mazda in Hiroshima, Japan, the model debuted in 1989 at the Chicago Motor Show. The MX-5 was conceived as a small roadster – with light weight and minimal mechanical complexity limited only by legal and safety requirements, while being technologically modern and reliable. The MX-5 is conceptually an evolution of small sports roadsters of the 1960s, such as the Triumph Spitfire, Datsun 2000, Alfa Romeo Spider, and particularly the Lotus Elan.
MegaSquirt is general purpose aftermarket electronic fuel injection (EFI) controller designed to be used with a wide range of spark-ignition internal combustion engines (not diesel engines). MegaSquirt was designed by Bruce Bowling and Al Grippo in 2001. The assembled controller takes input from several sensors in order to manage the fuel injectors, including a throttle position sensor, exhaust gas oxygen sensor, MAP sensor, tach signal, intake air temperature sensor, and a coolant temperature sensor. MegaSquirt is an affordable, standalone, mapable Engine Management System that can control the Fuel and Ignition on virtually any liquid fuelled spark-ignition engine, naturally aspirated or boosted.
As the car was already running when it arrived we ran it on the rolling road to check the power and the fuelling.
As you can see in the rolling road graph the car was producing 144bhp but the fuelling (the bottom graph) is all over the place.
The Eunos arrived running using a piggy back ecu but the proud owner wanted to change over to MegaSquirt, so the task of wiring in the ecu began. After the wiring loom had been fitted to the correct sensors etc. it was time to custom map the Eunos on the rolling road.
After several hours on the rolling road it was time to test the car on the road with the customer. The owner noticed the difference in throttle response immediately and then the power kicked in.
See if you can spot this Mazda Eunos in this short YouTube clip