PID

Hey Andre,

I have a question about tuning a 2005 Subaru Impreza STi (USDM) boost control system using the factory ECU and ECUFlash. I have added the Cobb 3 port EBCS and as you can imagine I needed to re-tune my boost control. I have completed the open loop set up with good results, minus a few hiccups at high load and mid RPM which I believe once I get the full system working together that will smooth out the hiccups. Anyways my question is on the PID system, which ECUFlash calls Turbo Dynamics, I have very defined proportional and integral (positive and negative) tables to adjust but I can't for the life of me find the derivative table. Any insight would be greatly appreciated.

Hi Brady,

Your system may only have P and I available, this leads to a system that isn't as affected by a noisy signal, but it can also be slower to respond to a real change in the signal as well. The Subaru inlet manifold pulses can be noisy, so this may have been used for this reason, rather than having to use a larger dead band for the signal to prevent the control chasing the signal. It can also be slower to respond to a large step change in the aim, so having a smooth boost curve will assist in the operation of a PI only system.

Ok excellent I will work though the process with the two parameters available. Thank you for your input.