My car currently sports Tial 770s, 4" to 2.5" super smooth y-pipe, SRM ICs, large Bi-pipes (and soon RS4 intake with Hemi throttle), 2.8 heads and I am having hard time controlling part throttle torque delivery. The ECU is using 5120 hack with real load, no underscaling (which is probably why I am having the issues, underscaled tunes are less sensitive to over-TQ situations).More specifically the initial onset of part throttle torque overshots the target value by a lot due to lack of WGDC control with high racking pressure on wastegates - tial 770s in mildest set up effectively delivers minimum of 21-22psi without any wastegate activity.

The ECU tries to moderate boost by closing the throttle which eventually settles boost/torque on the level I originally requested via gas pedal but to get there I am first hitting much more TQ.

Say I press the pedal to deliver 50% TQ and I initially hit 16psi which after some internal battling gets moderated down to 8psi and that's what the ECU rides at to red line. The whole process takes ~1-2s to settle.


What are your tuning strategies, or at least suggestions, to moderate TQ delivery in this situation without WGDC involvement?

Are there any maps that similarly to boost maps define aggressiveness of throttle activity to reach desired torque/boost or am I doomed to approach this with KFWDKSMX map and what else?


Thanks!

I don't see timing retard.

I tried adjusting wastegates to something smaller but tial packages ones with spring that starts moving at about 18-19psi so it cannot be lowered below about 20psi as it needs some preload.

due to packaging restrictions, any wastegate(s) small enough to fit the stock 2.7t location(s) don't seem to want to hold pressure very well with cracking at 1bar.


Not sure I follow. Rescaling hPa internally in ME7 won't change a wastegate's cracking and holding characteristics

N75 between 0 and 100% will make no difference whatsoever until 14-15 psi anyway.

You probably want to adjust FUEDK so that the ECU does not overshoot it's initial throttle control.

Pretty sure this does not exist in 551M and plgru_w = pu_w.
Besides, even if it was there, then from a quick glance I had a while ago, I don't see how calibrating this will affect this at all. Nothing you do to LDRPID is going to make a difference in this case.

The only thing you can do is with a stiff wastegate spring to lower filling is either close up the throttle or trigger the N249's.
IMO what needs adjusting is the filling adjuster, specifically the filling at a throttle position.
The throttle oscillation is the ECU incorrectly choosing the base set point, and the settling is the P controller working to equalize rl to rlsol.

So vpsspls_w?

And extrapolating on that - if BGPLGU is not there, then the only thing that can be done is tweaking KFVPDKSD and KFVPDKSE.

Yes.
If the base boost pressure is defined in BGPLGU or in LDRPID is not relevant. It's the same thing just another name.