C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Dumping the Optispark for good

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Old Feb 24, 2011 | 07:06 PM
  #21  
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Originally Posted by 89'Bowtie
We may need some of the guru's to confirm this, however if you plan to retain the LT1 PCM you can't completely ditch the opti.

At the very least the PCM needs the low resolution signal of the opti wheel to dictate engine TDCS to trigger firing.

You can make some adaptations to the crank wheel like the 96's have and put a decoder wheel there to id cyclinder positions (they exist and are made), but your running stand alone system.

The engine will run without the high resolution signals and set a DTC, but it needs the low res signal at the very least to run.

See this image below. There are 8 windows on the wheel that id the cylinder for the PCM.

http://www.corvetteactioncenter.com/...optispark8.jpg


I am not sure about the "stock" ECU, but if you swap it out for the '411 this is a piece of cake, plus the '411 has a faster processor, if my memmory is correct
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Old Feb 24, 2011 | 07:11 PM
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here is the February, 2009 issue of Popular Hot Rodding article about converting from TBI to LT1 intake, I will be taking it to the next level. To get the gains of sequential injection


http://www.popularhotrodding.com/tec...ls1/index.html

Last edited by tinbender59; Feb 24, 2011 at 07:19 PM.
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Old Feb 24, 2011 | 07:18 PM
  #23  
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Originally Posted by Charleston2012
If you really want to get rid of the Opti, do this kit. Then you can tune it so much better with more modern software.
http://www.eficonnection.com/eficonnection/24x.aspx
I looked into the 24X system, my wallet is still in shock 2 weeks later. and the EFILive system is what I will be using to tune my motor.
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Old Feb 24, 2011 | 07:46 PM
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Originally Posted by tinbender59
if you swap it out for the '411 this is a piece of cake,
But this now goes beyond your original " simple " intake mod in your original post to run a reg dist.
You now need a new ECM and custom harness for it all to work which most LT1 owners are not going to do
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Old Feb 24, 2011 | 07:59 PM
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Originally Posted by 84vette96
You have find tdc on #1 cylinder on the power stroke, then make your marks and a bracket pointer. Should not be that hard. You're going to have the front of the engine apart anyway.
From the factory, LT1 and LT4 engines do not have a keyway in the crankshaft hub -- aftermarket hubs are available with keyways.
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Old Feb 24, 2011 | 09:01 PM
  #26  
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Originally Posted by vetteoz
But this now goes beyond your original " simple " intake mod in your original post to run a reg dist.
You now need a new ECM and custom harness for it all to work which most LT1 owners are not going to do
OK I will take that one, you are absolutly correct on half of it, it will require a new ECM, but I do not believe ( in other words I don't know) that you could repin 90% then run a few aditional wires for the 411, as that is all that I have to do on my app.

I am doing an all out mod on my application, so it is not a big deal for me. but in a factory LT vehicle???? may be a dog of a different color?? when I am finished with my install, I will look into the "stock ECM" possabilities.
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Old Feb 24, 2011 | 09:13 PM
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It's a very endless list of possibilities when we start talking about new wire harnesses and new ECU's. I think the initial context of your post made readers think you were just looking to ditch the opti with minimal hardware upgrades.

I think this solves the questions about ditching the opti; it is only really possible with the application of considerable funds and hardware changes. Most people won't opt for this type of project.

I like where you are going though.
Good luck with it.
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Old Feb 24, 2011 | 11:55 PM
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Originally Posted by 89'Bowtie
It's a very endless list of possibilities when we start talking about new wire harnesses and new ECU's. I think the initial context of your post made readers think you were just looking to ditch the opti with minimal hardware upgrades.

I think this solves the questions about ditching the opti; it is only really possible with the application of considerable funds and hardware changes. Most people won't opt for this type of project.

I like where you are going though.
Good luck with it.

dont give up just yet, let me get mine done then I'll look into the stock ECM, by the way anybody have the Corvette wiring in software format that they could send me to resarch this issue. I am an electronics tech by training and 31 years experience. I should be able to figure it out, if not I know people!!!
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Old Feb 24, 2011 | 11:58 PM
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I've thought about doing a coil on plug conversion and updating the ecm to one out of an express van out of my own sick curiosity. But I have other priorities first. Looking forward to seeing how it goes!
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Old Feb 25, 2011 | 12:52 AM
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Originally Posted by dclafleur
I've thought about doing a coil on plug conversion and updating the ecm to one out of an express van out of my own sick curiosity. But I have other priorities first. Looking forward to seeing how it goes!
you are right on track with this project
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