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Thread: LT1 24X 411 PCM conversion - all of us please step inside

  1. #1
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    LT1 24X 411 PCM conversion - all of us please step inside

    Hey guys,

    I like several others am trying to tune my '96 LT1 Camaro with a 24X EFI connection. I would like to start of list of things that need to be changed from an '01-'02 F-body tune. From what I've seen of the tunes posted, I think there are some things missing. This list will ignore obvious engine/cam specifics that should be set with a WB and focus on those things that are LS1 --> LT1 specific.

    ENGINE - GENERAL

    Cylinder Vol. (may vary)
    Tach Output (from 6 to 3)


    ENGINE - IDLE


    IAC

    The LT1 IAC is different than the LS1. From what I've logged, it only works 0-200. So tune accordingly.


    IAC (LS1 range is 0-310, 365max and LT1 is 0-160, 255 max) [can we see the MAX number in HPTuners? Now we can. Thanks HPTuners!]
    IAC reset position (160 is working well for me)
    IAC Steps vs Effective Area (thinking this will need to be redone completely)
    Desired IAC area Max (???)


    ENGINE - AIRFLOW

    MAF airflow (I think the physical MAF is the same. Tune your MAF. Its a good idea anyway.)
    VE tables (will vary. Tune your VE tables)


    ENGINE - FUEL

    Injector bank select (A, D, F, G = 0 B, C, E, H = 1)

    Injector Timing (LS1 stock program has earlier injector timing than the LT1. Look at the thread below and use the EOIT spreadsheet to calculate the right value for your cam. I'm running Boundary = 7.1 stock normal and makeup for now)

    http://www.hptuners.com/forum/showth...ereencing-what

    Injector Flow Rate (set to flat value for your injectors, not the varying LS1 style)

    After start enrichment - the LT1 requires less cold start fuel than the LS1. My first stab I cut the Initial Adder table in half. Seems like a good start. Haven't changed it from the cut in half value. Working well.


    ENGINE - SPARK

    Spark tables - Lots of changes here. Hard to correlate the LT1 tables to the LS1 since the LT1 uses MAP vs RPM and the LS1 uses Cyl Airmass vs RPM. (Use L31 van tables?) [MikeOD suggestion below] {Van tables not really all that good either. Some tuning will be required here}

    Best bet appears to be a knock sensor from a 2002 Express Van 5.7L knock sensor -- 10456288 . I then plan to start with the express van knock tables.



    ENGINE DIAG

    ???


    TRANS

    Need help from the auto guys here as I have an M6.


    FUEL SYS

    Sender - Some have reported odd fuel gauge behavior. I bent my float when I installed the 255lph pump so mine has read strangely since before the 411 swap


    I'm sure this list is far from complete, but if we put all our lists together in one place it should help all of us and those that follow.

    Thanks,
    Jason
    Last edited by JasonS5555; 03-24-2015 at 04:49 PM. Reason: see changes in bold italics

  2. #2
    Senior Tuner Ben Charles's Avatar
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    When I get time Ill add to this, but the LT1 uses a Return Fuel system so values in IFR are the same across as well as the injector offset vs volts.

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  3. #3
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    Looking forward to Ben's input
    1994 Trans Am: LS3 Crate Swap - Cam Motion 216/226-116+3 - 0411 PCM with Lingenfelter 58x > 24x Converter - 4L60E to RPM T56 - Strange 12 Bolt - UMI Suspension - TSP 1 7/8" Headers - GMMG Exhaust

  4. #4
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    An L31 express van setup might be a better starting point for spark, as it's an 0411 PCM.
    2010 Camaro SS M6. Stock Bottom End, Heads/Cam/Intake/Headers/Exhaust.
    2005 Silverado RCSB. Forged 370 LQ9/Borg-Forced Inductions T6 S484/Jake's Stage 4 4L80E with D3 Brake/4WD.
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  5. #5
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    Hey guys,

    Thanks for your input. Lets keep it going.

    Ben, yeah I had the IFR as a flat value already, but do you change the IFR vs Volts from the 1.00 value that the LS1 tune has?

    Mike, is the L31 a Vortech SBC? (YES)

    Thanks!
    Jason
    Last edited by JasonS5555; 11-24-2014 at 12:40 PM. Reason: To answer my own question....

  6. #6
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    I updated some info above. Those of us with 24X conversions and the two butterfly style TB do need access to the MAX IAC steps parameter. See this post

    http://www.hptuners.com/forum/showth...-for-IAC-motor

    Jason

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    I updated the knock sensor section based on the 2002 express van. The knock sensor part numbers of interest are:

    1996 Camaro 5.7L knock sensor -- 10456287
    2000 Camaro 5.7L knock sensor -- 12589867,
    2002 Express Van 5.7L knock sensor -- 10456288

    So it appears that the Express Van knock sensor is different than either of the Camaro sensors and I'm betting that it has the body of the SBC sensor so it will screw into the SBC block, and different internals that are compatible with the 0411 PCM. So I plan to buy one and start with the express van knock tables.

    Jason

  8. #8
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    I've already got one. Just waiting until around April to do all the fluid changes and give it try. Good info.
    1994 Trans Am: LS3 Crate Swap - Cam Motion 216/226-116+3 - 0411 PCM with Lingenfelter 58x > 24x Converter - 4L60E to RPM T56 - Strange 12 Bolt - UMI Suspension - TSP 1 7/8" Headers - GMMG Exhaust

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    Added some discussion about after start enrichment

  10. #10
    Ok so i have Greg Banish injector data and how do i go about putting this info in for the conversion. Im running a 2002 fbody cal. im running the 30# skinny SVO injectors. thanks

  11. #11
    Once my set up is running better ill post the changes i made also....especially IAC stuff

  12. #12
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    Added a section on injector timing. The LT1 head is significantly different than the LS1 head and apparently GM was shooting the fuel at the back of the closed LS1 intake valve to vaporize the fuel and then the intake valve would open. This doesn't work as well with an LT1 head so I've moved the EIOT later. This is cam specific since the amount of overlap and cam intake and exh timing will impact when you want to have EOIT occur. So some thought will have to go into changing this number. The long post below is a great one on the subject and I've been using the EOIT spreadsheet posted to help me figure out what number I want to use. I'll tweak further once I have my WB installed.

    http://www.hptuners.com/forum/showth...ereencing-what

    HTH,
    Jason
    1996 Camaro SS M6 - 24X conversion - stock bottom end - heads - shorty headers - 58mm TB
    Ultradyne 230/238 .565/.565 112+4 - 30 LB red top SVO injectors - LOTS of suspension...

    2002 GMC 2500 HD Duramax M6 - Just starting the tune on a stock motor now that I have a good clutch on order...

  13. #13
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    just finished installing the Express van knock sensor after having tried a 96-97 fbody OBD2 sensor. The knock retard is finally behaving normally with the Express van sensor. I'm using a Delphi sensor from Summit, part # AS10015
    1994 Trans Am: LS3 Crate Swap - Cam Motion 216/226-116+3 - 0411 PCM with Lingenfelter 58x > 24x Converter - 4L60E to RPM T56 - Strange 12 Bolt - UMI Suspension - TSP 1 7/8" Headers - GMMG Exhaust

  14. #14
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    Very cool! Thanks for the update. I can't wait to get mine installed.
    1996 Camaro SS M6 - 24X conversion - stock bottom end - heads - shorty headers - 58mm TB
    Ultradyne 230/238 .565/.565 112+4 - 30 LB red top SVO injectors - LOTS of suspension...

    2002 GMC 2500 HD Duramax M6 - Just starting the tune on a stock motor now that I have a good clutch on order...

  15. #15
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    Another quick word. After driving for a while I was still getting max knock retard starting at about 50kpa. Tried desensitizing it as much as hptuners would allow, didn't work. Used VCM controls to hold timing at 20* with everything desensitized, didn't work. Disabled burst knock and knock learn, didn't work. So now I've set the knock detection mode back to cylinder. Stock Express knock settings have it at cylinder anyway. I just never get any knock in cylinder mode.
    Last edited by AdsoYo; 04-21-2015 at 06:50 PM.
    1994 Trans Am: LS3 Crate Swap - Cam Motion 216/226-116+3 - 0411 PCM with Lingenfelter 58x > 24x Converter - 4L60E to RPM T56 - Strange 12 Bolt - UMI Suspension - TSP 1 7/8" Headers - GMMG Exhaust

  16. #16
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    Have you tried bumping up the sensitivity to see if you get knock retard then with it in cyl?

    Thanks,
    Jason
    1996 Camaro SS M6 - 24X conversion - stock bottom end - heads - shorty headers - 58mm TB
    Ultradyne 230/238 .565/.565 112+4 - 30 LB red top SVO injectors - LOTS of suspension...

    2002 GMC 2500 HD Duramax M6 - Just starting the tune on a stock motor now that I have a good clutch on order...

  17. #17
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    That will be the next step ^ I just checked my drivers side spark plugs and they looked excellent for the most part, no evidence of detonation or pre-ignition. The ground strap showed evidence of too much timing however and that motivated me to overhaul my spark table. I searched high and low for a stock LT1 table and finally found one buried deep within the internet. I then transmogrified the table from the LT1's MAP vs RPM to the 0411's g/cyl vs RPM. What you see below is the basic shape of the stock LT1 spark table. I have modified it slightly (by removing 1-3* in some areas) due to my engines higher compression and cubes.

    Spark.jpg
    1994 Trans Am: LS3 Crate Swap - Cam Motion 216/226-116+3 - 0411 PCM with Lingenfelter 58x > 24x Converter - 4L60E to RPM T56 - Strange 12 Bolt - UMI Suspension - TSP 1 7/8" Headers - GMMG Exhaust

  18. #18
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    I did the same thing w regard to the timing tables. But I did bump up the area in the upper left where the car idles to match the idle table at around 33 deg. I think you have a copy of my tune. Right?

    Keep us posted on the knock sensor. I have one on the shelf, but haven't installed it yet.
    Last edited by JasonS5555; 04-23-2015 at 10:59 AM.
    1996 Camaro SS M6 - 24X conversion - stock bottom end - heads - shorty headers - 58mm TB
    Ultradyne 230/238 .565/.565 112+4 - 30 LB red top SVO injectors - LOTS of suspension...

    2002 GMC 2500 HD Duramax M6 - Just starting the tune on a stock motor now that I have a good clutch on order...

  19. #19
    Senior Tuner mowton's Avatar
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    So I was enjoying the movie.....how did it end?????????
    2004 Vette Coupe, LS2, MN6, Vararam, ARH/CATs, Ti's, 4:10, Trickflow 215, 30# SVO, Vette Doctors Cam, Fast 90/90, DD McLeod, DTE Brace, Hurst shifter, Bilsteins etc. 480/430

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    Senior Tuner mowton's Avatar
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    Ttt
    2004 Vette Coupe, LS2, MN6, Vararam, ARH/CATs, Ti's, 4:10, Trickflow 215, 30# SVO, Vette Doctors Cam, Fast 90/90, DD McLeod, DTE Brace, Hurst shifter, Bilsteins etc. 480/430

    ERM Performance Tuning -- Interactive Learning ..from tuning software training to custom tunes
    HP Tuners Dealer- VCM Suite (free 2hr training session with purchase), credits and new Version 2.0 turtorial available
    http://www.ermperformancetuning.com
    http://www.facebook.com/ERMPerformanceTuning

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