RomRaider

I'm trying to determine if the way my tuner has approached boost control is
1) consistant with other tuners
2) if i'm understanding the way the 16-bit '02 WRX ECU controls boost
3) if there's a better way to tune boost than my tuner has done.

My tuner has left the burst and continuous correction tables along, as far as I can tell, and has only adjusted the target boost values and maximum wastegate duty cycle values. He has set the target value above its actual target, then set the maximum WGDC lower than that, so that boost comes up quickly, then slams into a ceiling and stays there. It works great until you want to actually use some of the boost compensation factors, like for intake air temperature, for example. I have a problem with intercooler heat soak on track (road race car), and want to utilize that particular table. It doesn't do anything at the moment, because the target boost values aren't actually target boost values.

So, I adjusted the target boost values to what I wanted them (climbing to ~17psi), and cranked up the top-end max WGDC's. The boost control went NUTS!! It overshoots to 22psi, then oscillates continually b/w 12 and 22 psi until you lift off the throttle. My log is attached for reference, and I'll post my ROM when I can.

My question is can't I use the burst and continuous correction factor tables to control the dynamics of the turbo, as their names suggest??
How exactly does the Burst control work? I'm pretty stumped on that one in particular.
Many thanks!
-Matt McBride

read the sticky.

I did. I'm looking for more detail on how the burst table works. I know it's activated by quick changes in boost, but that doesn't seem to match what the activation tables say.

Is is acting as a damping coeficient, only active above a certain boost "velocity"?
-Matt

I'm not sure what you are asking. It is explained in the sticky:

"The correction from the turbo dynamics (TD) tables in this version is simply added to wastegate duty and limited by 'Max Wastegate Duty'. However, the TD tables are not active unless certain thresholds of boost error are met as determined by the 'TD Burst Activation Thresholds (Boost Error)' & 'TD Continuous Activation Thresholds (Boost Error)' tables.

The 'Turbo Dynamics Burst' table is the least used of the two correction tables. It is only active when boost error swings extremely quickly from negative to positive or vice versa (outside the range determined by the activation thresholds)."

As far as what "extremely quickly" means, it is when boost error is negative one execution and positive the next (or vice versa) outside the range detemined by activation thresholds, so we are talking about something that occurs very rapidly and only when going from a minimum pos. to neg boost error swing or vice versa.