Help me understand boost tables vs. WGDC tables
Posted: June 26th, 2025, 9:10 pm
So I'm super confused here. I've been reading everything I can about tuning, and I'm getting a pretty damn good handle on how these engines are managed, but one thing that still eludes me is what the purpose is for the wastegate duty cycle tables, since we have all of the various boost tables??? I mean, logically, if I am setting a boost table, then I would expect the ecu to target that boost pressure (or try to, until it hits another limit somewhere else in another table perhaps).
But then why have the wastegate duty cycle table at all? And if the WGDC table is adjusted, then how on earth is that not directly changing the boost pressure???
I honestly would have almost expected the ECU to vary the WGDC to cause a boost pressure it's looking for, using boost pressure as feedback on some sort of PID or PD control circuit. If boost pressure isn't as high as the table says it should be at this rpm/load, then it would increase the duty cycle on the wg solenoid until it sees the boost pressure it wants to see.
So can someone please explain this to me? @steve?
But then why have the wastegate duty cycle table at all? And if the WGDC table is adjusted, then how on earth is that not directly changing the boost pressure???
I honestly would have almost expected the ECU to vary the WGDC to cause a boost pressure it's looking for, using boost pressure as feedback on some sort of PID or PD control circuit. If boost pressure isn't as high as the table says it should be at this rpm/load, then it would increase the duty cycle on the wg solenoid until it sees the boost pressure it wants to see.
So can someone please explain this to me? @steve?