The Mazda RX8 is often critcised for poor performance so we considered ways to bolster the existing channels of naturally aspirated tuning methods to provide a cost effective method of optimising the fuel and ignition management to enhance it’s performance.

In conjunction with Mazda Rotary Parts, we initially conducted a base line dyno test with datalogging on a completely standard RX8 to establish it’s performance and engine management characteristics.

Here is the car hooked up to our Rototest chassis dyno:

The performance characteristics were as the manufacturers claimed, but the air/fuel ratio was far too rich and the shape if it’s fuel delivery curve was incorrect as can be seen from the datalogging graph below.

The green line below shows that the air/fuel ratio curve varies dramatically and reaches the excessively rich ratio of 11:1.

We selected the HKS FCON iS as the choice of aftermarket ECU’s for the management of fuel and ignition timing for this application because it is comes with a high quality harness to make connectivity a simple operation, and it’s level of quality and functionality is extremely high.

The main features of the FCON iS over it’s predessessing model FCON SZ are:

• A 25% faster processing speed.

• Built in video output function to monitor engine parameters.

Here are some pictures o fthe HKS FCON iS ECU.

Removing the front cover reveals the connectivity ports and dip switches.

The revere side shows the very high quality femail plug connector

Here is the “plug and play” harness which makes the connectivity very easy:

Here is the harness connected to the standard Mazda ECU:

For testing purposes, the FCON iS was not permanently installed so it was loosly mounted for the ECU tuning processes:

After correctly calibrating the fuel and ignition management we are able to demonstrate a significant increase in torque and power, and an improvement in fuel conumption:

Here are the “before and after” power and torque curves:

Here is the datalogging graph showing the optimised air/fuel ratio. Again, the green line is the AFR:

We have concluded that the HKS FCON iS is a cost effective performance upgrade solution on the Mazda RX8. For the more discerning owners or for those with turbocharged or supercharged models, the HKS FCON V Pro ECU solution is available which has significantly enhanced features and capabilities.