If you have a turbocharger pushing more oxygen into the engine then you need to add more fuel and adjust the timing or you will be seriously lean and produce knock. The timing/fuel is controlled by my Flyin' Miata Link ECU's air temp sensor, the Flyin' Miata knock sensor,and an LC-1 Wideband Oxygen Sensor. To get the extra fuel to the cylinders I use a custom made dual feed fuel rail and RC 440 fuel injectors.


The stock injectors put out fuel at a rate of 205 cc/min. The huge RC-440's put out 440 cc/min (over 2 times stock). Note the three large jets on the fuel injectors (left) vs the one small jet on the stock injector.



In a high boost engine the custom dual feed fuel rail ensures that fuel pressure will be the same on injector #4 as it is on injector #1. This helps solve the problem with burning up cylinder #4 when all the fuel pressure has been "eaten" up by the first 3 injectors. The new rail was made by tapping the far end of a stock rail with a 1/8" NPT tap and screwing in a 5/16" hose barb.



The Flyin' Miata Link ECU controls the timing and fuel system. It looks at a knock sensor and air temperature sensor to see if it needs to retard the timing. I mounted the air temperature sensor after the Flyin' Miata A/A Intercooler so the Link would know what the temperature was right before it entered the intake manifold. Here's the temp sensor and the housing I made for it (you have to look close - it's just a little green circuit board sticking out the end of the threads).



The knock sensor replaces one of the stock motor mount bolts (look right beside the oil filter). The sensor is really nothing more than a small microphone that tells the Link ECU when the engine is experiencing knock/ping/detonation and retards the timing to make it stop. Without this my engine would have been blown many times.