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Thread: Lt1 => Ls1?

  1. #11
    Lifetime Member N0DIH's Avatar
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    The 360 pulses are actually used on on the rising edge and trailing edge, so it is 360 slots making 720 degrees of res. Phenomenal resolution, best in the business, I don't think any engine ever got better. Then there is another slot in the wheel, a 10, 20, 30 and 40 (IIRC) degree res, which is used solely to determine where #1 is, so that there is the ability to start firing the engine within 90 degrees of engine rotation. Providing killer fast start ability.

    So you would need to translate the 360 pulses to the (24x?) res pulses the LSx needs, probably just as easy for any LSx PCM. And somewhere in the middle of that pulse, you need to introduce the additional pulses the LSx uses to determine where #1 is. Basically it has a fairly complex wheel that gives good detail at where it is while keeping the basic 24x resolution (like used as 48x, like the LT1 does by using the leading and trailing edge pulses.

    http://www.compstarcomponents.com/Cranks/LS1-Rear.jpg Study the wheel, you will see the 24x wheel, and the other wheel next to it, those together make the complex 24x that carries high res and discrete crankshaft location. Hard to explain really, but it is pretty cool how they did it. The LT1 is superior though for absolute precision, but the LS1 is dirt cheap and that is the name of the game.

    http://www.charm.net/~mchaney/optisprk/optisprk.htm

    So, can it be done? Sure. Take a little bit of thought, but honestly I don't feel it would be too hard. Might be a neat project to get looking at. I'll dig up in my 99 Truck FSM and see what the LS1 needs for signals and bounce it against my 94 Fleetwood LT1 FSM.

  2. #12
    Lifetime Member Cougar281's Avatar
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    Looks like one problem with the Optispark is if/when it goes bad, it's not cheap to replace...

  3. #13
    Lifetime Member Doc's Avatar
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    Interesting stuff. Thanks for sharing.

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  4. #14
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    Sorry to bring up an old thread here, but I too am curious to know what's involved in this... Also, Cougar281, the vast majority of Opti problems revolve around the distributor function of it (basically the cap/rotor). The optical sensors seem to be pretty reliable.I have a Del-Teq conversion on my '96 Impala, which uses the optical sensors on the Optispark, but fires the plugs via a Northstar-style coil pack setup. It seems to work well, I just wish they hadn't sent me wires that route the same way as the factory setup (but that's another story...). Anyone look into the LT1/LSx computer thing any closer?

    -Chris

  5. #15
    Lifetime Member GMPX's Avatar
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    ChipsByAl was on the money with the Express Van tune as a base.
    I think all the puzzle pieces are there to make it work I just don't know if anyone has gone ahead and taken the plunge.
    There was also a fella here in Aus that was looking at running one on a local Holden 5.7L, that also runs a dizzy with a cam pos sensor in the dizzy too, I think that is very similar to the Express van setup?
    Not sure how that ever ended up though.

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  6. #16
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    Quote Originally Posted by dfe1
    Negative-- the LT1 is a traditional small block, the LS-series has completely different architecture. In Fordspeak, the differences are like those between a 5.0 and a 4.6. Unlike the Fords, both of the GM engines are of the pushrod persuasion, but the blocks are totally different. Swapping an LSx in place of a conventional small block isn't terribly difficult, but does require some adaptation. Corvette Fever magazine is doing a project that includes installing a 5.3 LSx engine in an '87 Corvette, so that should shed some light on what it takes to do a quality conversion.

    I think it would be a kick to run an old-style small block, or any other engine for that matter, with an LSx PCM. I think that will really show off the capabilities of EFILive. I've been talking with a few people about doing a project like that. If it happens, I'll post the results.
    If I understand it, the World Products LSx block (they calit WarEagle or something?) has all the holes & mounting surfaces for both LS and SBC configurations, which might make things interesting. I believe I remember the GMPP LSX was planned that way, too, but not sure whether it stuck. Of course, I've slept since I learned all that so every bit of it is suspect...

    EDIT: OK, slept again... Remembered what I forgot, maybe.

    The WarHawk has both SBC and LS engine mounting provisions. The GMPP LSX block has ALL the holes of both the SBC & LS blocks.
    Last edited by gto_in_nc; August 11th, 2007 at 06:07 AM. Reason: 'Cause I'm a dumbass...
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