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Manual Boost Controller

Discussion in 'Modifications & Tuning' started by whitepunto76, Jul 28, 2015.

  1. whitepunto76

    whitepunto76 Regolare

    Messages:
    267
    Bangalore
    ECU varies the boost pressure using Pulse width signal (WDGC) along with temp changes/atmospheric pressure to provide linear boost curve and cut the boost in-case of failure. There 10-12 WGDC tables and 5-6 Boost tables to tweak the desired boost at various RPM levels.

    ECU controlling the Target Boost:
    Person driving around 70% throttle at 4000rpm hits 17psi
    ECU checks the WDGC with 50% signal. With 50%, boost is 12psi. Lets assume.
    ECU now calculates it needs 5psi more and adds more duty cycle.
    Probably at around 60-65%, ECU reaches to 17psi as desired.
    During this time, if driver rises/releases the throttle then again New Target Boost is desired.
    Again the ECU recalculates all over with above sequence.

    This way ECU tries to provide steady boost across the RPM based on throttle position.
    Within these calculations, ECU also massages few numbers based on air temp/rpms/specific gears etc to reduce the turbo lag.

    Pulsing Signal from ECU is controlled in WGDC tables.
    WGDC maintains % of how long the actuator is open within the normal operating frequencies
    More % of WGDC open = more air is fed to the system and delaying the wastegate from opening
    WGDT is operated on a square wave frequency.

    0% WGDC = Low Boost
    100% WGDC = Max Boost

    During the process of exhaust gases and turbines/compressors running, catalytic converter plays important role.
    CatCon acts like Exhaust Restrictions which would directly impact the WGDC & Boost tables.
    It means, to correct the WGDC/Boost tables the tuner has to fiddle around Exhaust Cam Timing Maps/Ignition Timing Maps/Compressor Maps/Min & Max WGDC maps/Desired Boost Maps etc.
    During these tweaks, the equilibrium has to be found to keep the Knock correction maps stable across the turbo band as desired by factory settings. These limitations forces some of the tuners to go for MBCs.
    Removing CatCon makes this equation much more complex for tuners to play around.
    That too here we are talking about FGT engine which has wastegate actuators. No vanes as in case of VGT.
    Till now I have not come across tuners who has tweaked the Boost/WDGC tables to increase the boost levels.
    Using MBC is not an offence/mistake given the expectation from it is kept limited to the usage of the engine/turbo setup.

    Goal:
    We all want more power with minimal investments to achieve the desired swoosh effect.
    This is never ending enigma for every enthusiastic driver to make his car performance oriented within the limitations of the engine setup.

    sample table of WDGC for reference.

    T8-WGDCMap.png
    varunrtr and asimpleson like this.
  2. asimpleson

    asimpleson Esperto

    Messages:
    3,000
    Heptanesia
    Linea 1.3
    @KKAUL,
    I know zilch about programming and the math involved let alone ECU programming. What I am trying to imply is you will really need to break it down a lot for layman such as myself and give more precise guidelines so that people can make more better and calculated decisions about tuning selections and aftermarket mods and such.

    Honestly about the previous post, I would want to understand, but honestly, I am wary personally if I really do want to understand that much in deep. Sample this, if I am in pain or if I want to be a performance athlete, what do I need, a performance drug or a painkiller with least side effects involved. Now the doctor tells me say about negative feedback and hepatic issues with too much technical detail, what will be my next question. Alright I need this and need this now, so either you give me whatever you think is safe or maybe I will need to look elsewhere.

    These modder have similar urges in my opinion. No doubt you are talking about making terminal mistakes but then they will want to buy opinion from a person who asks them to relax and take the risks. I am not suggesting anything to anyone here, these are my observations and we would be more helpful finding workaround or solutions. We say its not a problem with the car, you can and should adapt, but they feel completely opposite. So who is to say who is right. Just trying to put things in perspective.
    Last edited: Sep 21, 2015
    kunwar.g likes this.
  3. whitepunto76

    whitepunto76 Regolare

    Messages:
    267
    Bangalore
    @KKAUL & @asimpleson. Most of us at least me are not well versed with the practical/hands-on experience of these engine internals.
    It helps to have healthy discussions. No offence to anyone. We are all learning as and when we make these mods.
    Its also about taking risks based on one's appetite.

    I rather appreciate the questions brought out from KKaul and it makes us think more deep into the subject.
    But, we also need someone who can provide us indepth in layman terms to help us understand the merits/de-merits.
    I am not boasting of installing MBC or a remap. It was just a new experience for me to share this event. It may help others who are in same boat. I am not suggesting that we should go this route only. Options are multiple for any car modifications.

    Lets just stick to MBC or EBC topic. How we can use MBC/EBC in FGT/VGT puntos/lineas to make them performance oriented.
    vtlreja2 likes this.
  4. vtlreja2

    vtlreja2 Amatore

    Messages:
    214
    rajkot
    mumbai
    Grande Punto 1.3
    @whitepunto76 , I will be waiting for your long term usage report before plunging for MBC
    Interesting topic though,
  5. KKAUL

    KKAUL Amatore

    Messages:
    204
    delhi
    Grande Punto 1.3
    @whitepunto76

    Before installing MBC and after remap did you try to shorten the Link rod connecting the waste gate. You just need to have multiple link rod of different lengths to do more or less same thing
  6. kunwar.g

    kunwar.g Superiore

    Messages:
    522
    Gurgaon
    Grande Punto 1.3
    Meaning ? Would shortening the link rod ( assuming this is the pipe we are talking about ) lead to less loss of pressure or rather would result in more pressure. But again this will not enable to maintain at set psi... in my limited knowledge
  7. whitepunto76

    whitepunto76 Regolare

    Messages:
    267
    Bangalore
    No changes to Wastegate link rod. This was the first option given to mod the boost. But, risky to fiddle with those link rods.
    Have gone through few threads where tightening the link rod with some mod wastegate can hold the boost better.
    Hence, no tweaking of mechanical systems. Just the MBC fitment and control the boost.

    Just for information, the ECU boost limit is 21.76psi (1.5 bar). Above this engine will throw overboost error (P0234).
  8. KKAUL

    KKAUL Amatore

    Messages:
    204
    delhi
    Grande Punto 1.3
    The link rod with the spring setup hold the waste gate.Tightening the spring will result in more tension in spring to open the waste gate at lower rpm
    kunwar.g likes this.
  9. vtlreja2

    vtlreja2 Amatore

    Messages:
    214
    rajkot
    mumbai
    Grande Punto 1.3
    @whitepunto76
    Any approximate figure of power gain ?
    Any issues facing so far after setup ?

    Regards
    Vicky

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