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Thread: 09 G8 GXP Twin Turbo, 65lb Injectors, Zr1 MAP, Speed Density. Help?

  1. #1
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    Default 09 G8 GXP Twin Turbo, 65lb Injectors, Zr1 MAP, Speed Density. Help?

    Hey guys,

    This is my first EFILIVE experience. What a learning curve!

    I have been tuning with a wide variety of AEM products since 2004 with great success on a multitude of vehicles. I was just beginning to consider myself a decent tuner. EFI Live has humbled that thought to say the least.

    Where to start?

    First, setup.

    Stock LS3 in 2009 G8 GXP
    6L80 Trans
    65lb/hr Precision Injectors
    ZR1 MAP sensor
    AEM UEGO
    Twin 58/62mm Precision chargers
    No MAF as I have always tuned SD with AEM products.






    Problems:

    I can't get a Custom OS to populate the "Upgrade OS" table. I have followed the sticky instructions multiple times, plugged, unplugged Flashscan2, tried over and over. Nothing shows up in the CustomOS tab. This has me concerned. Ideas? I hope its me doing something incorrectly.

    Where I'm at thus far:

    Since I cannot load a COS, I decided to move forward.

    I have followed the VVE setup Tutorial and now have a good IAT reading. I have also scaled the MAP according to values I have found online.
    The car starts great, runs pretty well. I have not driven it. I have found a few different charts to compute these values, but they spit out different values. Which do I use and trust?

    What I'm struggling with is that I can't "see" where the engine is running at in specific maps that I'm viewing. Something is missing as I can't Upgrade 0S, nor can I "track the linked scan tool" in the Tune software.

    This is a general plea for help. I really wanted to learn this tuning platform for future endeavors, but bills need paying, and I don't want to make costly mistakes on a customer's vehicle.

    Tune currently loaded into vehicle:

    2bar Tuning.tun

  2. #2
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    OK, first off only the LS1B PCMs and E40 ECM for the gassers need to run a COS for boost. The E38/E67s are just fine using the factory OS, the only reason to go with a COS is for running dual fuel or N2O. You simply need to use the 2 or 3 Bar VVE table instead of the 1 Bar VVE table. It will recalculate the coefficients and let you run boost just fine.

    If the linked tables dont work, then you need to edit the correct .txt file (unfortunately I reformatted my laptop last wed and didnt install EFILive before I went on vacation and am using my phone for slow internet so I dont know exactly what file it is).

    Why are you anti-MAF? It is a very good instrument for measuring airflow, unless you are outflowing it (doubtful on a stock engine) it should give better results than pure SD.
    ~Erik~
    2013 Sonic RS Manual - 1.4L I4T E78, tuned, turbo mods, etc.
    2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
    2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.

  3. #3
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    Thanks for your fast response on a Holiday weekend!!!

    Thank you for also confirming the VVE tables that I need. You confirmed that everything I had read pointed to the 2bar and 3bar tables. I am assuming that primary timing is still adjusted via the Spark "High Octane Spark Table" ? Would I just copy and past the values into the low octane tables as well? Or will the low octane tables actually be beneficial?

    Finally, the "Injector Flow Base" Table values are not what any calculator online spit out. They are what enabled the car to start and idle at a decent AFR. Now that I know I'm tuning off of the 2b/3b VVE tables, I assume I would input more "proper" Injector Flow Base values, and then pull fuel out from the main table?

    I decided to ditch the MAF because I have always ditched them as practice. Most of them either ran MAP stock, or had tiny MAFs to begin with(my tuning experience is mostly Import related). I built the turbo setup around running maffless. It can be redone to accomodate the MAF again, but will cost me a lot of time to change everything around(12 hours or so).

  4. #4
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    Took the car for a drive last night. Seeing/feeling the differences in tweaking with the tables really helps.

    One of the main issues that I think I may have a beat on is that no matter now much fuel I had added to the 3bar table, the car would still stay ~14:1 in boost(less than 2psi, peddling it). I have since disabled Long Term Trims via B1510, as I'm pretty sure the 02s were pulling fuel. I'm testing this out shortly.

  5. #5
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    Car is going into a reduced power mode. It pulls -25 degrees of timing at anything above 100kPa. For kicks, I copied and pasted b5101 into b5157. Whoah, got power back!! Luckily I had plenty of fuel. However, this doesn't feel like the "right" way to go about it, I have to find out why the car is in a reduced power mode.

    It has to be related to the speed density conversion(or lack thereof). Any thoughts?

  6. #6
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    No expert here, but I dont see a log with some of your issues posted. You might get some more help if you posted one up.
    1997 S10, 06 trailblazer SS LS2 swap, 4L70E trans, 76mm turbo. Factory ZQ8 suspension. 3.08, G80 w/a zexel. With a 0411 swap.

  7. #7
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    You still have torque management in full operation. Any knock causing this?

  8. #8
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    Also im not sure you can just expect to use 2 or 3 bar ve tables just because they are there. wouldnt you have to enable it first? It is not a factory boosted car is it? Might have to enable B8028.
    1997 S10, 06 trailblazer SS LS2 swap, 4L70E trans, 76mm turbo. Factory ZQ8 suspension. 3.08, G80 w/a zexel. With a 0411 swap.

  9. #9
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    Thanks guys!

    I wasnt sure if I should completely disable torque management. Anything to keep the actual spark table where it should be operational would make my life a lot easier. As far as knock, I'm having a hard time trying to figure out where the timing actually IS right now. With so many background trims, how am I supposed to know? lol. I took a best guess...it seems to be low.

    The B8020 Table looks like it's spot-on!!! I kept running out of fuel at 4000rpm. Makes sense, as thats all that the RPM read up to. In the file I attached below, I had already made changes and saved them.

    Also, the most recent log. I had added fuel to cure the 4000rpm leanout(therefore its now rich), but she still leans out. It will probably cure itself after the above changes. I finally cracked a beer for the 4th, no more datalogging tonight. Thank you guys for the help. The car is getting to be very fast. Baby Steps....

    3bar MinTim TorqueReducParamOffBurstKnockdumbed.tun4th gear test full.efi

  10. #10
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    First off, NO to the copying high and low ocatane tables!! Big no-no, it is ok when you have it strapped to a dyno and are figuring out the best spark values, but I usually take my high octane table and pull anywhere from 4-6* out of it and use that as a baseline low octane table for street driving. That way the knock sensors can do their job and also it helps compensate a little for bad gas.

    What are you using for your IFR, should be using the info that came with your injectors. That should be "known" data (hopefully!), then you tune according to them. Trying to fudge IFR usually ends up with a lot of wasted energy and time, set it correctly then the rest of the fueling should be a lot easier to dial in.

    Why are you only running like 8* of timing? From the other FI LSx motors Ive seen they usually run 14-18*. Also you're running 10.5:1, seems a little rich for a FI motor to me (thought most are closer to 11:1), but use whatever the engine likes for power!

    Looks like ~4400rpms is when it started leaning out, by 4700 you're running 11.5:1, at 5000 its up to 12:1. Hmmm, are you running out of injector then? (Log injector duty cycle, not in that log) Or is the fuel pump not able to feed the injectors at those RPMs?
    ~Erik~
    2013 Sonic RS Manual - 1.4L I4T E78, tuned, turbo mods, etc.
    2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
    2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.

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