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Thread: 2009 STS-V LC3 WOT Boost Cut

  1. #1
    Tuner in Training
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    2009 STS-V LC3 WOT Boost Cut

    Hello everyone,

    I have a weird Boost Cut right after shift to 3 gear from 2nd. It goes from about 15-16PSI of boost down to about 8-9. The car has a 4" intake, 2.55" Upper Pulley, 7.5" lower pulley ring, 630cc injectors, and some intercooler upgrades. It was not tuned by me originally as I am very new to tuning. If it is a relatively straight forward fix, I'll give it a shot. I have updated some Supercharger TM, it seemed slightly more responsive but it still cuts boost. I have attached a log and the current tune file. Thanks in advance!





    2009 Cadillac STS-V Updated TM.hpt
    2009 STS-V Boost Cut Log.hpl

  2. #2
    Advanced Tuner PGA2B's Avatar
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    Contact Tim Coeling.

    @TimC

    He should be able to help you get it straightened out.
    2013 OBM A6 CTS-V Coupe
    Mods: Headers back Billy Boat Exhaust, GripTec 2.65, 8.6 PowerBond Lower, LSX Innovations Solid Isolator, ID850's, NGK TR7IX's, Accel 9070CK Wires, Spectre CAI, SRI Ported Throttle Body, SRI Catch Can, NGK AFRM, 160* T-Stat, 0fx2gv Brick, Hard Line Delete W/3/4" Lines, FB 101 FMIC, Pierberg CWA50, Stoptech Drilled/Slotted Rotors, EBC Redstuff, Cut Stock Springs, Flat Bottom Steering Wheel
    2006 Black Raven STS-V (Traded In)
    Fully Modded: 459RWHP@5888rpm/451lbft@4696rpm

  3. #3
    Tuner in Training
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    I'll send him a message. I also had the thought that I might need to install a 3-bar MAP sensor. I'm running about 15.5PSI of boost and 2-bar MAP sensors are rated for 14.7PSI of boost. What do you guys think of that?

  4. #4
    Tuner in Training
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    I ended up fixing my boost issue, it was caused by two problems. I was maxxing out the factory 2 Bar MAP at 15.5 PSI of boost, so I upgraded to the LSA 3 Bar MAP and changed the parameters accordingly for the sensor. The other problem was TM was cutting boost because of high IAT2 temps, that was solved by installing a bleeder hose on my heat exchanger and refilling/bleeding the system.

  5. #5
    Senior Tuner
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    Quote Originally Posted by northstarV View Post
    Hello everyone,

    I have a weird Boost Cut right after shift to 3 gear from 2nd. It goes from about 15-16PSI of boost down to about 8-9. The car has a 4" intake, 2.55" Upper Pulley, 7.5" lower pulley ring, 630cc injectors, and some intercooler upgrades. It was not tuned by me originally as I am very new to tuning. If it is a relatively straight forward fix, I'll give it a shot. I have updated some Supercharger TM, it seemed slightly more responsive but it still cuts boost. I have attached a log and the current tune file. Thanks in advance!





    2009 Cadillac STS-V Updated TM.hpt
    2009 STS-V Boost Cut Log.hpl

    In the torque management section there is boost limiters (reads like 60%) if you exceed 250F IAT. I saw it reduce boost before it got to 250 (240F) but maybe the rate at which it was increasing qualified it somehow for reducing the boost.

    You got to get that IAT in control. I dont' know anything about a STS but if I see a boosted car hit 170 I'm looking at options on what to do.. 250 is crazy.
    Tuner at PCMofnc.com
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  6. #6
    Tuner in Training
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    I had the same thought on the torque management at the rate it's increasing. I did fix the IATs, my intercooler kept purging the coolant out because of air bubbles in the system. I installed a coolant bleeder hose on the heat exchanger and re-bled the system. The IAT lives around 100-110 now with 70 ambient.