Update on the Electronic Boost Controller
No matter what implementation of PID calculations I tried, or what gain constants I set, the wastegate responded way too quickly to duty cycle manipulations and it was impossible to curb the oscillations with any values for constants.. Besides that, the MAP sensor voltage needed to be filtered because of the fast response times of the ADC on the micro-controller I used for this project.
Today, after 100 kilometers alternating between hard full throttle runs and idling in the midday sun, during which the car was very well-behaved with no overheating, no funny business - only an anemic, struggling air conditioning compressor at idle - I decided to implement a simple bleed valve configuration for more predictable results and to "scale" the stock wastegate response curve.
The end result?
No PID, just simple logic statements that de-energize the solenoid at vacuum, and energize it with a fixed duty cycle percentage when boost is detected. Dramatic difference, no more oscillations, engine behaving as it should, massive low-end (2000rpm lol) torque with just under 100 kPa / 14.5 PSI of boost.
I neither have the fueling nor the tooling to go beyond that number, and it's already only achievable by defeating the stock overboost fuel cut built into the ECU with a zener diode voltage clamp.
I think I'm satisfied. The car feels like a different animal between 2500-4500 rpm with essentially double the factory boost, and a much earlier spool-up time.
Still a small animal, but different nonetheless.
To help make the welcome a little better, a splash screen.
Another task coming up: read a thermocouple and don't raise boost unless the oil/coolant has fully warmed up. Stock threshold until warm, after which it gradually increases, only allowing full boost at or above 82°C operating temperature.
