Stall / Idle Surge Turbo FRS

[DarkPira7e]

Datalog - https://datazap.me/u/darkpira7e/idle...?log=0&data=18

Trying to figure out what to try next. Tuner hasn't had much time to play with it so I'm seeing what you all think. This is most easily provoked if you give the car between 5% and 10% throttle slowly ( as if you are taking off from a stop) and let off quickly. Stabbing to 3k RPM, it usually doesn't happen. Holding the throttle at 5-10% creates significant surging for a few seconds.



What to know-

This car has a MAF delete and the blend tables no longer help us
This car has a 10.6lb flywheel
No vacuum / boost leaks
ID1050x
AEM 340LPH fuel pump
No fuel pulse dampers installed on rails
Car drives fine under all other circumstances
10.5:1 Compression ratio shortblock, still pulls 21-23hg vacuum at idle

@tomm.brz mentions switching to euro maps, but commanded fuel injection type appears to be functioning correctly.

[tomm.brz]

don t really know as of yet what s wrong, i would start with trying to improve the SD ve table, activating the CL fuel control even at low rpm and low load (even if it then fights a bit against the normal fuel trims)

lightweight flywheel can be annoying, could help to make the idle stability strategy more aggressive
i dont get why ur tuner kept 12.16afr as minimum afr for the stock lambda, like oem tune
anyway, is your tune open?

[DarkPira7e]

Originally Posted by tomm.brz

don t really know as of yet what s wrong, i would start with trying to improve the SD ve table, activating the CL fuel control even at low rpm and low load (even if it then fights a bit against the normal fuel trims)

lightweight flywheel can be annoying, could help to make the idle stability strategy more aggressive
i dont get why ur tuner kept 12.16afr as minimum afr for the stock lambda, like oem tune
anyway, is your tune open?

Yeah he said he wants to work on VE table for lower RPM. Seems to go pretty lean just before it wants to stall out so he probably wants to fatten up the fueling a little down there.

The tune isn't locked, I don't have a copy of this revision though. I can see if he'll e-mail me a copy tomorrow when I go visit.

[tomm.brz]

i see the PI is already shut off at low load but i see a little activation during those blips, could be worth disabling them a little more
even if those ID inj are pretty precise though, if you manage to recover the unlocked tune i l ltake a look with you if you want

[AussieBRZ]

Ok

Compare the log when you blip the throttle and it doesn't stall to when you blip the throttle and it stalls


Most things seem the same port zero direct injection about 0.9, fuel rail pressure similar manifold pressure similar but when it stalls it's rich like 13 afr and when it doesn't it's 16-20


Also when it stalls the stft is way negitive when it doesn't it's near zero



Maybe leaking injector or bad earth on di computer or some strange issue?


Is that an SD tune at idle or using maf ?

[tomm.brz]

it s 100% sd, the maf isn t even plugged

i d try add also the cl fuel control at low rpm and load, even if it s tricky as it s then mostly on subaru closed loop so it could not work, also i think the lightweight flywheel could be at blame, i add a guy who stalled like this often after installing the hks flywheel on my tune and all i did was timing more aggressive for the idle strategy, a littlw bit higher idle and raise a bit the fuel cut off reinjection

[AussieBRZ]

Originally Posted by tomm.brz

it s 100% sd, the maf isn t even plugged

i d try add also the cl fuel control at low rpm and load, even if it s tricky as it s then mostly on subaru closed loop so it could not work, also i think the lightweight flywheel could be at blame, i add a guy who stalled like this often after installing the hks flywheel on my tune and all i did was timing more aggressive for the idle strategy, a littlw bit higher idle and raise a bit the fuel cut off reinjection

Do you know what racerom version some early racerom had some SD bugs that caused weird stall from memory

[tomm.brz]

it is quite old actually i think RR10

#Ecu 1 CALID: ZA1JA01C
#Ecu 1 RaceROM version: 32145

version 10 was a bit buggy actually yes
Surely worth to upgrade it to RR12.1... also switching to ZA1JA02G could be good

[DarkPira7e]

Thank you both! Definitely going to go back to a normal flywheel at some point, this isn't worth it. Ran great with MAF blending helping out, but I think a little too touchy now

[tomm.brz]

buddy i took a look at your tune, apart from how he set the PI injectors in a totally different way from how everyone is doing (and how ecutek instructs) it looks ok... PI are almost not used in the zone you have problems so it doesn t really matter this
the stock lambda is untouched and capped at 12.16 AFR because you have a wideband and he is using that with forced closed loop all time

i bet 95% your guy is a Wrx tuner lol, seeing how he set everything up
specially the cam timing i totally don t like, he s using basically wrx jdm cam timing but brz heads flow totally different

i would probably just upgrade racerom to 12.1 and try to mod a bit the sd ve tab and the idle timing strategy for your stalling

btw, very powerfull config!! more than 1.4Bar of boost
the maf g/sec calculation i think it s a bit miscalculated because it ia using 65% of PI but the PI compensation against MAP is kept fixed at 1.0 instead of rising against positive boost, that makes the PI squirt less than ideal so it is compensated by rising the SD VE values ( you have zones with 135% of VE and the closer loop still adding 5-10% of fuel more.. nothing bad with this anyway, your afr is still fine) but i think you could be close to 400whp with 93 octane??

[DarkPira7e]

Originally Posted by tomm.brz

buddy i took a look at your tune, apart from how he set the PI injectors in a totally different way from how everyone is doing (and how ecutek instructs) it looks ok... PI are almost not used in the zone you have problems so it doesn t really matter this
the stock lambda is untouched and capped at 12.16 AFR because you have a wideband and he is using that with forced closed loop all time

i bet 95% your guy is a Wrx tuner lol, seeing how he set everything up
specially the cam timing i totally don t like, he s using basically wrx jdm cam timing but brz heads flow totally different

i would probably just upgrade racerom to 12.1 and try to mod a bit the sd ve tab and the idle timing strategy for your stalling

btw, very powerfull config!! more than 1.4Bar of boost
the maf g/sec calculation i think it s a bit miscalculated because it ia using 65% of PI but the PI compensation against MAP is kept fixed at 1.0 instead of rising against positive boost, that makes the PI squirt less than ideal so it is compensated by rising the SD VE values ( you have zones with 135% of VE and the closer loop still adding 5-10% of fuel more.. nothing bad with this anyway, your afr is still fine) but i think you could be close to 400whp with 93 octane??

Thank you! This config isn't optimized yet, we're going to be fixing the fueling system so we can run an FPR to keep rising fuel pressure at 1:1 ratio with boost. Are you saying there's a way to ask the system to automatically adjust in line with positive manifold pressure above 1 bar?
In this config, we had about 400whp. We had it up to 470 at 25psi of boost but did not like the VE table compensating so much for the fuel pressure getting out of whack.
Yes, he is primarily a WRX tuner! haha

[tomm.brz]

yes, your tuner just flattened it to 1 everywhere, i ll post a screenshot as i get home
Also there is plenty of headroom with the injectors, your DI opening time doesn t go past 4.9ms so you can raise DI %
PI opening time can go up to 16ms more or less and yours don t go over 8ms

[tomm.brz]

the table i was talking about
right is stock, left is yours
bottom is the right one, copy that for your tune



Keep in mind it will inject more fuel from PI with this so you should probably adjust then in SD VE tab and reduce value


Also, fuel pressure in this car is 58psi normally, so better values for your id1050x are this probably:



Other good things for the injections could be these:



i think 65% of PI use is too much as you have in your tune, anyway you should aim for a maximum DI opening time of 5.4-5.5ms full throttle so regulate considering this.. honestly i would use 50-55% as maximum PI use if you use 93oct
65-70% would be good if you plan on using E85

Rising the value in DI firing angle will advance it so you are more sure that it won t end firing when the spark occurs
Also raise this: (you have 1.1 at the mom)






idle stability control #1 #2, try to fit the bottom table (from any restyling tune like K00C or Q00G or more recent) to your tables ... they made it smaller so you ll have to stretch and interpolate it



also try using these timings for idle:

[tomm.brz]

cam timing

these are yours, and they too much WRX lol





these are made by hri a while ago, they work good
can also reduce a bit intake cam advance at high load as you have more boost





this a different approach, more stock feeling under vacuum but still work good