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Thread: LSA breaking up under boost

  1. #1

    LSA breaking up under boost

    LSA car. Just got the car back together after porting the blower and snout, adding a 102mm, and changing pulleys (went from 10psi to about 15).

    So over 80% throttle or so, and over 12-13psi, it stalls out like it's on the stock limiter for about .5 seconds, then comes alive again for .5 seconds, etc.... and it's very repeatable. All I can see in the logs is that maf/map values drop hard during the dead period. I took several logs. Fuel pressure is mostly good. It kinda jumps all over during the breaking up, and I don't blame it for getting confused. I'm going to double check my plug gap in the morning, but I'm pretty sure they were at .025. I guess I'm just curious if anything jumps out at you guys here.

    I've attached 3 logs. The last one has 2 back to back short pulls on it.
    Attached Files Attached Files
    '12 ZL1 - RPM 5", TSP 2" headers, Speed Engineering 3" header back, Dayco 8.66 lower/LPE 2.38 upper, ID1050x's with DSX aux kit and E, NGK TR8's, Taylor wires, 160* tstat, NW 102, self ported snout/blower, Stock unopened long block

  2. #2
    Advanced Tuner PGA2B's Avatar
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    Have you changed your Map Disable/Enable under Engine>Supercharger>Torque Management>Boost Disable?
    Last edited by PGA2B; 07-29-2020 at 11:11 PM.
    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
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    Seems to be a common miss in the tune with these cars. Gotta go raise your MAP disable/enable values. It's cutting boost at the stock limit of 192 kPa. Push those up to 250/240 or 255/245 or something similar.

  4. #4
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    LOL. beat me to it.

  5. #5
    NO crap. Thanks guys. Right now I just have the map disabled for MAF only while I retune. I didn't even think about it still tripping out over other parameters. Funny thing is, I even looked at that and saw it hitting 192 over and over thinking that was weird lol
    '12 ZL1 - RPM 5", TSP 2" headers, Speed Engineering 3" header back, Dayco 8.66 lower/LPE 2.38 upper, ID1050x's with DSX aux kit and E, NGK TR8's, Taylor wires, 160* tstat, NW 102, self ported snout/blower, Stock unopened long block

  6. #6
    So I wasn't even talking about the same thing lol. Under Airflow/General/MAP estimation, does that need messed with? Because it was also set to 192 for max.

    I did find what you are actually talking about. Such an easy thing to look over. I'll be honest I spend almost no time in the torque management area being a manual car.

    I really owe some of you guys a beer.
    '12 ZL1 - RPM 5", TSP 2" headers, Speed Engineering 3" header back, Dayco 8.66 lower/LPE 2.38 upper, ID1050x's with DSX aux kit and E, NGK TR8's, Taylor wires, 160* tstat, NW 102, self ported snout/blower, Stock unopened long block

  7. #7
    Advanced Tuner PGA2B's Avatar
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    I would make that the same as your setting for MAP Disable under the Supercharger Tourque Management. I have mine set to 256 for Disable and 255 Enable to make sure I don't get near them.
    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

  8. #8
    Well that fixed it. Thanks guys.

    Now I've found I'm at the limit of the aux pump. By A LOT.
    '12 ZL1 - RPM 5", TSP 2" headers, Speed Engineering 3" header back, Dayco 8.66 lower/LPE 2.38 upper, ID1050x's with DSX aux kit and E, NGK TR8's, Taylor wires, 160* tstat, NW 102, self ported snout/blower, Stock unopened long block

  9. #9
    Advanced Tuner PGA2B's Avatar
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    Stock Heads and Cam?
    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

  10. #10
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    I know we've got two threads between the two forums, but I'd say first let's make sure the tune is properly set up to take advantage of the aux pump.

  11. #11
    Quote Originally Posted by PGA2B View Post
    Stock Heads and Cam?
    Yes sir.

    Quote Originally Posted by RobZL1 View Post
    I know we've got two threads between the two forums, but I'd say first let's make sure the tune is properly set up to take advantage of the aux pump.
    Yeah I posted the tune on google drive over there because it doesn't allow hpt files lol.

    here it is again. Not sure what I'm missing there, I wasn't aware there was much to adjust besides commanded pressured and duty cycles.

    https://drive.google.com/file/d/1ujB...LgaxBcY49/view
    '12 ZL1 - RPM 5", TSP 2" headers, Speed Engineering 3" header back, Dayco 8.66 lower/LPE 2.38 upper, ID1050x's with DSX aux kit and E, NGK TR8's, Taylor wires, 160* tstat, NW 102, self ported snout/blower, Stock unopened long block

  12. #12
    and a log file to go with it. The 2nd wot run really shows how bad it gets. It's not super consistent, but usually drops well into the 40's
    Attached Files Attached Files
    '12 ZL1 - RPM 5", TSP 2" headers, Speed Engineering 3" header back, Dayco 8.66 lower/LPE 2.38 upper, ID1050x's with DSX aux kit and E, NGK TR8's, Taylor wires, 160* tstat, NW 102, self ported snout/blower, Stock unopened long block

  13. #13
    Advanced Tuner PGA2B's Avatar
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    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

  14. #14
    Quote Originally Posted by PGA2B View Post
    I might be too dumb to make use of that lol
    '12 ZL1 - RPM 5", TSP 2" headers, Speed Engineering 3" header back, Dayco 8.66 lower/LPE 2.38 upper, ID1050x's with DSX aux kit and E, NGK TR8's, Taylor wires, 160* tstat, NW 102, self ported snout/blower, Stock unopened long block

  15. #15
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    I'd read and re-read Dave's blog post until it makes sense. Basically, you haven't licensed and tuned the FSCM as far as I can tell (it's not included in the tune file you sent, at least). It looks like all that has been done is to bump up the normal and low flow desired fuel pressures in the ECM.

    Therefore you are still stuck with a 65psi (450kPa) maximum due to the stock limit in the FSCM. The computers are basically fighting your aux pump. It looks like the aux kicks in around 170kPa, starts to rise, and then gets pulled back down. I'd first ensure you raise your FSCM max desired pressure and regulation pressure to 600kPa. Then go get another log and see what it looks like.

    Either that, or you have already done that work in the FSCM, and what we see at 170kPa is just the step up to the "high flow" region and possibly the aux pump isn't coming on. Probably less likely since the pump was already working before the last round of mods.

  16. #16
    I have read the fpcm, but havent changed anything in it yet because everything was working dandy until this last round of work lol. I did run another log with commanded pump DC, and it stayed at 100% and only dropped to about 55psi (not sure if actual was 100% because that parameter doesn't show up). Then right before peak boost, at about 6100rpm, it dropped to 50%, and the car fell on it's face again like a rev limiter. MAP was reading 217kpa at that moment, and then peaked at 220 exactly for a bit before everything dropped because I was idling. I have no idea what that was about.

    I've attached the log and current fpcm tune
    Attached Files Attached Files
    '12 ZL1 - RPM 5", TSP 2" headers, Speed Engineering 3" header back, Dayco 8.66 lower/LPE 2.38 upper, ID1050x's with DSX aux kit and E, NGK TR8's, Taylor wires, 160* tstat, NW 102, self ported snout/blower, Stock unopened long block

  17. #17
    I'll raise the desired pressure to 70 in the fpcm and try again.

    Also, is there an actual fpcm controlled regulator in the pump, or does it only use pwm/voltage and a hard set regulator to regulate flow?
    And should I mess with the max desired boost at all in the fpcm? It doesnt seem to be effecting anything yet since it's set at 160kpa

    EDIT: I should clarify what I meant about the article. I think I mostly understand how the ecu/fpcm communicate, I'm just not able to understand how that article might help trouble shoot this particular case. Unless, like you said, it's just an argument between the 2 about what actual fuel pressure should be. This is the most important part I picked out of it:

    "The most important table that is almost always neglected by the less informed is [FSCM] 6994 - Maximum Desired Pressure. For a few vehicles (namely fifth gen Camaros and the SS Sedans), this table is crippling when trying to use an aux pump if it is not addressed. No matter what you do, the FSCM is going to fight to drop fuel pressure even if you're asking for 500kPa... unless you raise this table. When the FSCM gets a request for the ECM, the first thing it does is check against this table, and if this table has a lower value, it will trump the ECM request. As a followup to this table, [FSCM] 6995 - Regulation Pressure should be raised as well for good measure."
    Last edited by madmikeismad; 07-30-2020 at 10:45 PM.
    '12 ZL1 - RPM 5", TSP 2" headers, Speed Engineering 3" header back, Dayco 8.66 lower/LPE 2.38 upper, ID1050x's with DSX aux kit and E, NGK TR8's, Taylor wires, 160* tstat, NW 102, self ported snout/blower, Stock unopened long block

  18. #18
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    i have done all them yall talked about when she get hot it goos nuts
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  19. #19
    Finally got some time to log with the fscm adjusted. I can clearly see now when it's commanding 100% and fuel pressure actually goes back up after the correction when the aux pump kicks on. I'm still dropping below 60psi when commanding 70psi, so I'm pretty sure I'm just out of pump, at least on E.
    '12 ZL1 - RPM 5", TSP 2" headers, Speed Engineering 3" header back, Dayco 8.66 lower/LPE 2.38 upper, ID1050x's with DSX aux kit and E, NGK TR8's, Taylor wires, 160* tstat, NW 102, self ported snout/blower, Stock unopened long block

  20. #20
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    Good news. Sounds like you're on the right path to figure it out. It does actually get to 70psi before it drops, right?