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If you have an Audi 2.2 20VT please make a boostlog run for me,im totally disapponted of the performance of my turbo.
In 1-3 gears im unable to maintain more than 0.8-0.9 bar,may boost is only achivable in 5th gear.I really would like to compare my runs with other 20VT owners.Thanks in advance //Peter
So finally,after 1 year i decided to install the N75 WGFV,and control it via VEMS.
I know from MiskaPeippos? page that i have to drive this with a free injector driver.So this will provide the negative voltage,and i should wire the other pin to ignition positive?
- Injector driver provides switched GND to N75 valve and in stock wiring harness 12V is provided together with injector supply.
- I have no exactly correct values, but you can try with ones I picked from MembersPage/Fero
- Boost conf=105 Sets PWM period to 6 (*8ms), MAP target active and reference position.
- Actuator off below this pressure=130kPa Defines lowest pressure when boostcontol starts to do something (I think AAN had a bit higher nominal pressure than 0.3bar boost achieved with wastegate spring)
- Target offset=0
- choose correct channel (INJFET and proper channel with not i)
- Set boost vs. rpm and boost vs. TPS tables as you like
- Try with following settings
- boost P=45
- boost I=27
- boost D=250
- PID integral limit=255
After installing the mechanical parts and configured the ECU,i started a LLOOOONNGGG PID tuning session. I educated myself with the help of GRMracer (thanks a lot!).
Basially i used the method describer at wikipedia,tried Feros initial Boostconfig,nothing worked.after 2 hours of continous testing,i decided to make a basic test.With only P variable (ID zero) i should have a huge oscillation,while the desired target is beeing overshoot.Now that is what wont happen at all.I cant get more boost than 1 bar (200Kpa) with P only,which makes me wonder,is this really a PID control?
Please dont try to tell me what mechanical parts to check,the whole thing is allright,its a pure programming/controlling issue => likely bad configuration of reference position ?
Every part of the system is STOCK, so no problems here (?). How was it verified ?
I also tried to choose the best working PWM period.
with the lower (2-8),and only P max(200-255) waiting for oscillation nothing happened (max160-170kpa),and with 15msec perion and 200 P there was a slight oscillaton (200kpa + - 10kpa)
Note that the actual target was 230kpa,which was NEVER reached under the whole session. This is a good point to start ! Does it reach 230kPa with the valve fully open (100% duty?). I'd start with refpos = 80%. refpos=60% might be possible, but I highly doubt 20 or 40% would be good (from this fact that 230kPa was never reached).
Any suggestions are welcome, i made numerious log (10+).
http://www.vems.hu/files/MembersPage/NanassyPeter/BC_logs => useless without the matching config
''Of course there is the matching config in the filename,for example
means date_(period in MT)_P_I_D_Ilimit''
Note how the link is changed. after uploading, rightclick on the link for the copy-URL-to-clipboard (not copy from browser URL-line).
I dont have such feature in Firefox ,only a copy link location
I will also try Miskas settings.
After some more testing i found the roots of the problem:looks like the valve cannot do all the 0-100% DC,it only wors good in a certain region.That is why i can achive a rocksolid 170 and 180 kpa boost (even with much stiffer WG spring).This means for me that when the WGFV must open less (0-50%) it control fine,but when more opening is needed it fails (say 50-100%).
When it has to bypass little amount of air (when choosing lower targets like 170kpa) it can do the job,but when more volume of air must be bypassed (higher boost target) it fails.
This confirms the reference position suspicion.
Did you try what we discussed on phone? With reference position=80% (sufficient boost_conf value) so there is some chance to get reasonable boost behaviour.
An experiment to
- disable boost output
- configure idle PWM solenoid
- idle period = 40 msec or so
- idle output controls boost
- take log with accel run with different duty on the boost solenoid
- mdi01 (almost 0)
- mdi10 (1/16 duty)
- mdi20 (1/8 duty)
- mdi40 (25% duty)
- mdi80 (50% duty)
and even higher if the boost doesn't go too high.
Comparing the max boost will allow calculation of good initial P,I,D values
Note that i also added a restriction in the system (before it had a diam 2.5mm, now it has a 1.5mm diam)