Dumping the Optispark for good
Thread Starter
Intermediate
Joined: Feb 2011
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Dumping the Optispark for good
As most of you know the company that had been performing this mod are MIA. so today, I dropped my LT1 intake off at a machine shop to accomplish this mod once again! The operator Is going to build a jig to accomodate the proper location and height of the distributor hole. Of corse we will have to use a mock up motor to get this right "IE My motor" then he will transfer that to the jig for future mods. once this is done, he will be able to turn more intakes out rather rapidly. please let me know if you are interisted in having this done? I do not know the cost yet, mine will be the most expensive I would guess, I get to pay for all of the R&D go here to follow my LT1 install into a 1997 K1500 Ex-cab SBSS http://chevroletforum.com/forum/showthread.php?t=40408 
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
Would be of more interest to those wanting to do a LT1 intake conversion on a L98 than LT1 owners themselves
LT1 owners tend to upgrade to LSX style coil paks rather than take a step backwards to a old style dist
LT1 owners tend to upgrade to LSX style coil paks rather than take a step backwards to a old style dist
Race Director
Joined: Jun 1999
Posts: 14,924
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From: Merritt Ils Fl
Burning Brakes
Joined: Apr 2001
Posts: 1,209
Likes: 0
From: Toronto Ontario
St. Jude Donor '13
I would agree that the upgrade to the COP (coil on plug) setup from the LSX is a better way to go. Coils can be had very cheap and the ability to control and have precise high rpm control of the ingition is more advantagsous for an LT motor considering it's higher rpm nature or any other motor. The only down side is the look of the coils that don't fit under the covers, but that is subjective.
The HEI system was good for it's time, however we've come along way since the days of distributors. No worries of igintio break down, interference, etc with COP. Plug more energy on demand if needed as 1 coil has plenty of recharge time on an 8 cyc. car if each cyclinder has its own coil.
I don't think it is worth the step back in technology.
The HEI system was good for it's time, however we've come along way since the days of distributors. No worries of igintio break down, interference, etc with COP. Plug more energy on demand if needed as 1 coil has plenty of recharge time on an 8 cyc. car if each cyclinder has its own coil.
I don't think it is worth the step back in technology.
Last edited by 89'Bowtie; Feb 24, 2011 at 11:31 AM.
Racer
Joined: Apr 2006
Posts: 327
Likes: 0
From: edgerton WI
I have seen mud trucks with LT1 engines in them. The first thing they do is ditch the opti. I don't know who did the machine work on the intake however. With a used intake going for $50 Their might be a market to sell these to hot rodders building budget small blocks.
Burning Brakes
Joined: Apr 2001
Posts: 1,209
Likes: 0
From: Toronto Ontario
St. Jude Donor '13
That makes sense, the opti is no resiliant to water, moisture, and debris.
The modded LT1 manifold can have some good applications and the design of the manifold is very supportive of high rpm breathing.
Personally, I would leave the opti on the street. But that subjective I suppose.
Good luck
The modded LT1 manifold can have some good applications and the design of the manifold is very supportive of high rpm breathing.
Personally, I would leave the opti on the street. But that subjective I suppose.
Good luck
Thread Starter
Intermediate
Joined: Feb 2011
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I agree that COP would be preferred, but the cost I quite painful, and UGGLY to boot. I work in the aircraft production industry, and 90% of the sale Is appearances, you can build it perfectly but if it looks ugly you have a white elephant. kind of sticks with you through out your whole life
Safety Car
Joined: Dec 2008
Posts: 3,588
Likes: 10
From: North New Jersey
As most of you know the company that had been performing this mod are MIA. so today, I dropped my LT1 intake off at a machine shop to accomplish this mod once again! The operator Is going to build a jig to accomodate the proper location and height of the distributor hole. Of corse we will have to use a mock up motor to get this right "IE My motor" then he will transfer that to the jig for future mods. once this is done, he will be able to turn more intakes out rather rapidly. please let me know if you are interisted in having this done? I do not know the cost yet, mine will be the most expensive I would guess, I get to pay for all of the R&D go here to follow my LT1 install into a 1997 K1500 Ex-cab SBSS http://chevroletforum.com/forum/showthread.php?t=40408
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Pro
Joined: May 2008
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I think this is a very good alternative to the opti and the expensive individual coils (I personally have never seen a "cheap" set up like that). What I am wondering is how does this effect the computer? What else do you have to do computer wise to run with out an opti and with a regular distributor? Thanks, I am interested.
Burning Brakes
Joined: Apr 2001
Posts: 1,209
Likes: 0
From: Toronto Ontario
St. Jude Donor '13
I think there are some details that needed to be worked out.
You can trigger and ignition module to fire a coil via a distributor and completely bypass the PCM. This is possible and has been done. The question is what is the PCM going to do if it realizes it isn't controlling the ignition? Possible a DTC?
A GM HEI distributor could run the ignition completely independently, however I think you'd still want the PCM ignition signal to control your timing because it will best decide timing for idle, loads, knock, etc.
Your challenge is getting the PCM to still control timing and just use the distributor to trigger the module.
Let me do some research and maybe I can post something back to help you out.
Vic
You can trigger and ignition module to fire a coil via a distributor and completely bypass the PCM. This is possible and has been done. The question is what is the PCM going to do if it realizes it isn't controlling the ignition? Possible a DTC?
A GM HEI distributor could run the ignition completely independently, however I think you'd still want the PCM ignition signal to control your timing because it will best decide timing for idle, loads, knock, etc.
Your challenge is getting the PCM to still control timing and just use the distributor to trigger the module.
Let me do some research and maybe I can post something back to help you out.
Vic
Le Mans Master
Joined: Sep 2005
Posts: 6,551
Likes: 36
From: Jenks OK
I agree that COP would be preferred, but the cost I quite painful, and UGGLY to boot. I work in the aircraft production industry, and 90% of the sale Is appearances, you can build it perfectly but if it looks ugly you have a white elephant. kind of sticks with you through out your whole life
Burning Brakes
Joined: Apr 2001
Posts: 1,209
Likes: 0
From: Toronto Ontario
St. Jude Donor '13
I will admit, the problem with the COP is that it still uses the opti to determine engine position via the decoder wheel inside the unit. You are still subject to optical sensor failure.
Le Mans Master
Joined: Sep 2005
Posts: 6,551
Likes: 36
From: Jenks OK
Isn't there a setup using components from a Chevy express that eliminates the opt?
Burning Brakes
Joined: Apr 2001
Posts: 1,209
Likes: 0
From: Toronto Ontario
St. Jude Donor '13
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
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
Melting Slicks
Joined: Jun 2010
Posts: 2,178
Likes: 1
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
http://www.eficonnection.com/eficonnection/24x.aspx
Thread Starter
Intermediate
Joined: Feb 2011
Posts: 33
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yes there is, by using a 12200411 LS1 ECU and swapping various filles in and out of the ECU to build your own custom "program" then put it on a dyno for fine tunning. this all has already been worked out. I even have the wiring documentation from a build that was done years ago for my 1997 4X4 pickup. which uses inputs from the 4X4 system.
Thread Starter
Intermediate
Joined: Feb 2011
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Not true any more, use a '96-'97 LT1 front cover & sensor for CMP signal ( I Already have one) then use the vortec distributor for cam position and you are ready start rewiring.
the really cool thing of the '411 is you can use it for 4cyl, 6cyl, 8cyl, TBI, TPI, LT1, LS1, batch fire mode, sequential fire mode.. it is wide open as far as I can find out. basickly any fuel injection can be run on it, you just have to figure out the sensors and signals it is way cool
P.S. timing is set just like a Vortec or LS1
Last edited by tinbender59; Feb 24, 2011 at 07:16 PM.