Which Harness ECM to use LS1 or LS2

Discussion in 'High Tech Retrofits' started by SS Performance, Mar 2, 2017.

  1. SS Performance

    SS Performance Veteran Member

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    I'm building a bored and stroked LS2 that was resleeved for my 70 Camaro. Now it is 454. I'm using ported LS7 heads and either a Hi-Ram or Super Victor intake.

    My question is should I get a LS1 harness and ECM or a LS2 ECM. The motor has the 24 tooth reluctor wheel so the early LS2 ECM would work.

    Either harness would need to be modified for stand alone and I don't want to use drive by wire. The trans will be a T56 Magnum. Eventually I was planning to go with a Dakota Digital dash.

    I have found several places that list which wires can be eliminated from the LS1 harness but haven't found any for the LS2.

    What are the pro's and con's for each?

    Any suggestion or advice would be appreciated.

    Thanks
    Craig
     
    Last edited: Mar 2, 2017
  2. badazz81z28

    badazz81z28 Veteran Member

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    I'm using a stand alone harness from PSI. I would not waste the $300 on an OEM harness and pay someone $500 to modify it when you can get one from PSI ready to go for $500.
     
  3. 71RS/SS396

    71RS/SS396 Veteran Member

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    For what you're trying to do I would probably go with the Holley Hp ecu and harness. If you use the 411 (LS1) ecu and harness you're going to have to do something about the the wiring for the front mounted cam sensor on the LS2 and also extend the knock sensor wires to mount the knock sensors on the side of the block. I've never seen a LS2 dbc ecu and harness so I have no input on that. Why the High Ram intake? They aren't very good for n/a engines. If you go with the 4 bbl style tb use a 4500 series, the 4150 tb's only flow about what a 90-92 mm flow, which will likely not be enough for that many cubes. I have a 450" LS and initially started out with a Fast 102 but it choked the life out of it above 6,300 rpm, I ultimately ended up with a twin tb intake with 2 90mm tb's which resulted in a 50 hp increase over the Fast and the engine is happy to rev to 7,800 rpm.
     
  4. badazz81z28

    badazz81z28 Veteran Member

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    ^^if PSI has a LS2 harness for the 411 PCM , the harness will be long enough for the sensors
     
  5. SS Performance

    SS Performance Veteran Member

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    Which intake did you settle on? I already have the Hi-Ram it was originally purchased for a different project that never got finished. I was thinking about using the stock ECM and getting HP Tuners to tune it. I could use the tuner on my 02 and 15 Camaros as well.

    Thanks
    I'll have to give them a call.
     
  6. 71RS/SS396

    71RS/SS396 Veteran Member

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    I used the OZMO Engineering intake.
    I don't like the 411 ecu, it's too slow and can be very difficult to get good idle/low speed manners without stalling and surging when you have a cam that doesn't make good vacuum. You will pull your hair out trying to get the mechanic idle set with a low iac count without surging. I've seen some cases where it's necessary to drill a bleed hole in the throttle blade to get them to idle properly. My wife's car had that ecu with a 427, Fast 102 intake and tb with a fair amount of cam in it, I have fought and fought with the idle and stalling at clutch in. If I had the time I would yank the harness and ecu out of it and put the Holley in it.
     
  7. QUAKE_WARS

    QUAKE_WARS Veteran Member

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    I used a NEW PSI harness. Great price and great people.
     

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