Engine Drivetrain 2nd Gen S Most liked posts in thread: R56 MCS Boost Limit Can Be Defeated

  1. oldbrokenwind

    oldbrokenwind Active Member

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    #4 oldbrokenwind, Dec 2, 2012
    Thanx Jason, information is always good. Here in Northern NV, my home elevation is about 4500' --- causes some weird boost gauge readings. I've learned to live with it. Besides, when at high RPM / boost, there's little time to watch a gauge --- torque steer is fierce on my Mini.

    Enjoy the drive ---
     
  2. oldbrokenwind

    oldbrokenwind Active Member

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    #2 oldbrokenwind, Dec 1, 2012
    My AP data logs now show boost "spikes" up to the Manual Boost Controller setting, currently about 22psi, as measured on my external boost gauge, then the AP readings settle down to the FCD settings. This "spike" lasts for about ½ minute.

    Does anyone know how the boost reading, at the AP connector, is calculated? There must be some other boost input to the ECU, because I've got the 2 MAP sensor outputs limited with the FCD zener diodes.

    Before the FCD install, this MBC setting would cause an overboost cel, WGDC readings of 0.0%, and other errors. At 25psi there are no errors --- even this “spike†is being tolerated by the ECU. Performance increase is noticeable, but without a tune for the extra boost, I’m not going any higher with it --- FEAR!

    I’m still trying different ways to lose the “spikeâ€, but no progress yet. A little “theory of operation†would be really helpful.
     
  3. Jason Montague

    Jason Montague New Member
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    #3 Jason Montague, Dec 2, 2012
    :cornut:I don't know whether this info helps or hurts but here goes. On Margi(08 R56 MCS/JCWm) I have a 'ScanGauge II' and I monitor the MAP(manifold absolute pressure) which is ambient barometric pressure plus boost pressure. She also has Alta CAI/turbo intake pipe/intercooler intake and out let hoses which delete the turbo muffler and the cabin noise maker. As here in Sherman, TX we're at 300 ft above sea level, I just mentally subtract 14(usual sea level pressure is ~14.7psi) from the MAP and call that my boost. The highest MAP that I've seen on Margi is 30.5 in 3rd gear @ 6krpm in over boost accelerating onto the highway. So the highest boost that I've seen on Margi is ball park 16.5psi briefly in over boost. When I shifted to 4th the boost came back down out of over boost. Anyway, that's my experience with boost/over boost on Margi.:Thumbsup:

    Jason
     
  4. SacredDisorder

    SacredDisorder Because Race Car?
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    #5 SacredDisorder, Dec 28, 2012
    I have been contemplating doing this for a while now. Which wire was the signal wire for the FCD? I am looking at ordering two Turbosmart FCD's hopefully that will do the job. Just need to find what wire is the signal wire for both.

    -Brian
     
  5. Dave.0

    Dave.0 Helix & RMW Powered
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    #6 Dave.0, Dec 28, 2012
    Torque Steer....ahhh just another added benefit of the Gen 2 cars.

    All kidding aside, good luck with your project.
     
  6. oldbrokenwind

    oldbrokenwind Active Member

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    #7 oldbrokenwind, Dec 28, 2012
    Here's an excerpt from my journal. The complete FCD install process is on the last couple pages, starting at "November 2012". The journal is located in "my garage", attached to the first post.

    "Connecting them to the sensors was not as simple as it could have been. MAP sensor on the manifold is 3-wire, while the sensor over the wheel well (2 different sensors) is a 4-wire harness. The 3-wire setup was easy enough --- power source is a twisted pair leaving only the signal wire. The 4-wire harness uses the same colors as the 3-wire with the obvious 4th wire. Problem is, the boost sensor wire is not the same color in both sensors, as I assumed it would be. Power source is the same color twisted pair. So I had to re-do that one signal connection."

    Sorry, this doesn't specify the color as requested. Actual colors are not that easy to determine --- they're faded and work wasn't done in good light. Doing the 3-wire sensor first will help.

    Had to re-adjust the FCD settings --- was getting "funny" readings on my data logs. This time, the FCD settings are closer to exactly alike --- 3.9VDC. I'm still working on getting a dyno tune. With the holidays, people are scarce. Received a "remote tune" for my AP, and it's working pretty good, but the boost is only around 23psi. If nothing else, the FCD's will eliminate the spikes, so boost can be adjusted closer to the 22psi limit.