Suzuki Marine DF40A outboard engine tuning – stage 1 Remap 33950-88LF0

A 40 BHP Suzuki Marine DF40A outboard engine was sent in to us for a stage 1 remap from a customer in Italy using our postal remapping service.
The engine was a the DF40A which we can easily remap to the DF60A settings, this is because the engines are the same inside, only the ECU software is different.

The ECU fitted to the Suzuki Marine engine was a Mitsubishi Melco with part number 33950-88LF0. We analysed the software from a DF60A ECU with part number 33920-88L31 and after a couple of hours of work it became clear which maps were responsible for the maximum allowed power.

This ECU regulates the throttle flap to control the maximum air mass allowed in to the engine, and the ECU works in a closed loop mode monitoring the lambda sensor to adjust fuelling accordingly. This ensures a safe and correct air fuel ratio.
By allowing the throttle flap to open more we increased the amount of air entering the engine, in turn the ECU adds more fuelling to keep Lambda precisely controlled and we get more power.

In this case we increased the 3d torque model to the same settings as the DF60A, and then added a little more power on top as we know it's safe to remap the DF60A on stock hardware too. This means we ended up with a nice 65 BHP whilst keeping the engine very reliable. With such a big power increase it's always a good idea to fit a larger prop to the engine to make use of the powerband in full.