RomRaider

I noticed recently that my -almost- stock 2011 EDM STi has some anti-lag action during gear shift.

I have not really spent time to figure out what the activation conditions are, but when enabled, the fuel injection is cut-off but a -20° total timing is applyied at lift-off (or during gear shift) in the 4200 down to 2800rpm zone, the residual fueling resulting in some pop or bang (single pop or bang !).
As far as I could see (and log), this feature is not active for a 2nd gear pull, shifting or not, but above 3rd gear for sure.

Anybody ever noticed or logged same ?

Bôh t'as vu ça où coco???

effectivement, cousin, c bizarre...

I'll make a couple of dedicated logs and upload them here asap les amis

Done some testings today, but didn't see anything looking like what you described.

ils sont ou vos logs

Hi folks, sorry for the delay... I had no time to log the car, away from home.
Here is a narrow cut of the log where I initially spotted those corrections.
You'll notice the boost was exceeding 2.55bar absolute during set-up.
This is not my target (obv), that was the purpose of the loggin, but it's still the same on an actual 2.40bar steady boost target.

This ROM has been altered in various data places (fueling, ignition timing, cam timing, boost control), but the code is still 100% original.
As far as I can explore, I didn't spot any -20° value in any ignition table neither correction...

I am quite surprised XN could not reproduce this as I am on almost any lift off...

Thanks for the log.
I've done again the same test, but I didn't experience your negative timing values during lift-off around 4300 rpm.
Look at my attached file.

It is not anti-lag feature at all since there is no air\no fuel injected.
Possibly this helps to pass the fuel from inlet walls directly to the cat for afterburning to avoid carbon deposit inside the cylinders due to rich spikes during lift-off.

You are correct, fueling is zeroed as soon as ignition gets negative.
But it has some slight antilag effect has I described initially : some residual fuel (injected before the cut) is ignited in the exhaust for a single pop at almost any lift off.
More than a log, I'll try to capture this with a cam if I can manage.

More like transient ignition retard, to smooth out timing between shifts

This is used alot on most after market ecus

This is not the case.
Antijerk ignition retard is used when throttle is open sharply.

It will be over run ignition trim then, commonly used on the over run fuel cut, switches injectors off and trims ignition

Your requested torque tables are not lining up properly. The DBW acc, DBW, throttle, requested torque (RPM), target boost and WGDC are off somewhere in the scalings. Make a copy of your file, zero out your fuel/ignition timing/AVCS settings, then PM me the file. I can point out where the problem lies. My bet is on the 2D req torque (RPM) table.

There probably is something wrong since nobody else has seen this, but this function is actually used in some EMS's as "gearshift support" function, to make the engine drop to synchronious rpm quicker.