OK. for those of you that want to rid of their opti that are knowledgeable about what needs to be done, please post here.

I was speaking to my boss today and he said he had the extra time to work on some electronics to replace the optispark. What would probably happen is you would still use the opti portion of the optispark but eliminate the destructive high voltage section. This system could be either similar to the SDI or maybe a multi coil setup like the LS1.

Anyone that could supply pertinent information to develop this product will be appreciated. If I can get an idea of what has to happen, he has the capability to design AND build this product in house. He stated price would not be able to be beat.

So.......This just may be our chance to get that fix we have all been waiting for.

Injuneer?? Any other SDI users (besides myself) or people that have knowledge as to what has to be done to make the coil per cylinder systems, please contact me or reply here.

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1994 Z28 A4, Vortech, Flowmaster, TPIS 52 mm TB, Hooker LT's, LS1 brakes, AAM 3.42 rear, more.

 

I guess it would look something like this:

http://cjcfo.fbody.com/members/injun...os/Coils01.jpg



------------------
Fred
94 Formula A3: 381/TH400/N2O
Detailed Mod's List
11.513@115.59 on motor; 11.162@127.67, 1.643 60' on a 125-shot. Going with a 275-shot this year

 

Look like that, maybe. But are you still utilizing the STOCK PCM for that?? I think I would probably do an over the valve cover coil setup to make it easier to access and also keep them out of the elements and away from flying road kill.

I want to have an interface built that allows people on a budget to use their stock PCM. If that means using coil packs like the SDI, so be it.

I know you know quite a bit about this so could you fill me in a bit? Pictures don't really tell much; your experience with the design or idea will be much help.

THanks,

Ryan

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1994 Z28 A4, Vortech, Flowmaster, TPIS 52 mm TB, Hooker LT's, LS1 brakes, AAM 3.42 rear, more.

 

First off I'll state that I know next to nothing about the SDI system, however, I've been thinking about this and at least on the surface of it, it seems like the electronics shouldn't be too complicated.

The PCM knows which cylinder is going to fire next because it sends off a signal to cycle the fuel injector. The PCM fires off the coil, which then goes through the distributor cap to the correct spark plug. Could this "black box" take the information from the fuel injector, take the output from the PCM to fire the coil, and then redirect that coil signal to the correct 1 of 8 coils?

I don't know if that's very clear so I'll give an example using specific cylinders. Lets say the motor is running and cylinder #6 is going to fire next. The PCM cycles the #6 fuel injector and then a short time later the coil fires off. The energy is directed to #6 plug only because the distributor mechanically directs it to #6. Well, the box would take the output of the PCM for the injector and coil. When it "sees" that #6 fuel injector has cycled, it "knows" that #6 coil is up next, so it directs the output from the PCM which would normally fire the single coil so that it fires coil pack #6. The exact timing would need to be determined, since the injector fires on the intake stroke and the coil fires on the compression stroke.

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Hear LT1 cam WAVs, DIY head porting: members.***.net/gmarengo

'95, !CAGS, CAI, ForceII, Hooker Shorties, 14.2@103

 

If the price was right I would be in.

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96' Z28,Artic White, 6spd,T-tops, leather.
Mods: Yeah I got a couple
My Z

 

The stock PCM needs to know the exact postion of the camshaft, so it knows which injector to fire (in a sequential sytem). In the LT1, it only know this because it gets the low res pulse from the Opti. This is the heart of the problem. The stock PCM needs a high and a low resolution pulse to operate.

Electromotive used a crank timing wheel..... then synthesized the low res and high res pulses that would normally come from the Opti. It fed those pulse signals to the stock PCM, which did its normal thing as far as firing the injectors, and sending the signal to the IC module to fire the plugs. E'motive intercepted the spark signal from the PCM, and used it to drive the 4-coil pack.

The whole problem with the E'motive system, and with any system that uses only a crank trigger, is that the PCM doesn't get all the info it needs to fire the injectors and plugs correctly. The crank has to rotate two times before the engine fires all 8 cylinders. With only a crank trigger, the PCM doesn't know which pistons are approaching TDC on the compression stroke, and which ones are approacing TDC on the exhaust stroke.

E'motive solves the spark problem by using one coil to fire two cylinders (so does GM on the V6, and on the Buick GN/GNX) at the same time. One is on the compression stroke, and the plug ignites the mixture and does its "normal" thing. The second cylinder is on the exhaust stroke, so when the plug fires, nothing happens - this is called the "lost spark" method. Works fine for ignition.

Where you get into trouble is with the injectors. On a 93, the E'motive system workd fine... batch fire, one bank at a time.... PCM could care less which cylinders are approacing TDC on compression. Case solved for all 1993's.... install E'motive Opti-Eliminator/SDI.

For the 94 and ups it was a problem.... on 1/2 of the starts, the chip weould synthesize the low res pulse, but then synchronize it 180-degrees out of phase. At low loads, the injectors were firing against closed valves on the power stroke, instead of into open valve on the intake stroke. At WOT/max load, this becomes less significant, since the injectors are open most of the time anyway. Surprisingly, this had little affect on driveability, except for a minor stumble off idle when the engine was ice cold, and the fuel was puddling on the cold valve instead of vaporizing on the hot valve.

All that E'motive needed to do to make the O-E/SDI work was provide a correct "synch" signal for the low res pulse. That could have been accomplished by using just the low res pulse from a working Opti, or by adding a cam positions sensor in place of the Opti. They knew this, took the system out of production to solve the problems.

There was also a problem that something in the O-E/SDI system prevented it from working with OBD-II. Someone had done an O-E/SDI install on an OBD-II Impala SS, and E'motive ended up installing a complete TEC-2 system for the guy to make it work. The TEC=2 could live with the out-of-phase injectors, because it was NOT a true sequential injection.... it fired two injectors at once, an a sort of "semi-batch fire" system.

The engineer at E'motive ("JC") felt he could solve the problems. I was there once and he showed mt the 1996 Z28 he had bought with is own money to use as the test mule. He wanted to work on it, but E'motive had other plans, and other products, and never gave him the time or the resources to solve the problems on the O-E/SDI. The fact that they claim to have an O-E interface to the new TEC-3 system leads me to believe he eventually solved the problems. Somebody ought to contact E'motive and see where they are with that system.
--------------------
Ryan:

No, my current 8-coil system does not use the stock PCM, and would be a god-awful expensive solution if you tried to use it only as an ignition system.

You prefer mounting the coils on top, and then using "over the top" wiring. That would look like this - my E'motive O-E/SDI with Taylor 409 wires:

http://members.aol.com/InjuneerZZ/im...otos/eng02.jpg

http://members.aol.com/InjuneerZZ/im...otos/eng01.jpg

http://members.aol.com/InjuneerZZ/im...otos/sdi01.jpg

Fred


[This message has been edited by Injuneer 94FormM6 (edited June 03, 2002).]

 

Fred:

A guy I talked to said he figured the problem out for the sequential fire. He only used the OE as an "extension cord" to feed the crank trigger signal to the SDI. He left the optical portion of the optispark hooked up and that is what ran the computer. He stated as long as the crank trigger was timed properly it worked great. Until he actually got it timed correctly, he said the PCM would throw a code because it was confused.

All he did was left the plug on the right side of the intake untouched. The PCM got the high and low res pulses it wanted and was still able to control timing and retard. The SDI was happy because it was using the crank trigger to get its spark going. He told me he had run this system for the past 4 years on the street with no problems. Seems his solution was quite simple; have you heard anything about doing this??

Ryan

 

This has been one of the most talked about mods in this section so I'll post some links and pics from what I think is the best way to rid of the opti. It's a little pricey though.

Here's the pics if using a crank trigger and a cam sensor: http://www.nedyno.com/contest.htm


Here's the thread:
http://web.camaross.com/bb/Forum30/HTML/000602.html

 

That's a nice setup but the point of what I am going to do is to make something that uses the stock PCM -AND- is reasonably priced so more people can afford it. What will be built WILL be a pretty much plug and play deal that any person with even minor mechanical knowledge will be able to install in an afternoon. I don't want any crazy rewiring to be done; just unplug factory connectors and plug the module in.

 

The stock PCM needs to know the exact postion of the camshaft, so it knows which injector to fire (in a sequential sytem). In the LT1, it only know this because it gets the low res pulse from the Opti. This is the heart of the problem. The stock PCM needs a high and a low resolution pulse to operate.

Right, and as I understand it, the whole point of Ryan's post is to use the stock PCM and create an add-on black box to supplement the PCM/Opti. The purpose of the black box would be to direct the "fire" signal that would normally go to the single stock coil and direct it to the correct 1 of 8 coils. All the information to do this is already available with the stock Opti and PCM. What I'm talking about would only move the high voltage out of the Opti -- and as I understand it, that is commonly believed to be the biggest problem with the Opti.

If I understand what you've said, the information to fire cycle the injector comes from the Opti itself. If that's so, the box would take that information and fire the correct coil when it "sees" the signal to fire the coil -- except that it would direct the signal to the coil that matches the injector number based on information it receives from the Opti.


------------------
Hear LT1 cam WAVs, DIY head porting: members.***.net/gmarengo

'95, !CAGS, CAI, ForceII, Hooker Shorties, 14.2@103

 

I guess it comes down to the reliability of the Opti. I obviously believe the optical section is reliable, and more reliable when you remove the high voltage functions from the front of the case. I use the Opti exactly that way to drive the 8 LS1 coils. And George Baxter has used the same setup for 4 years on his 9-second 30th SS Convert.

However, neither my car or George's can be considered a "daily driver". My car seldom sees the rain, has been averaging only 2,000 miles per year for the last couple of years. And I started 2 years ago with a brand new, vented Opti conversion.

I think the solution needs to address the concerns of the average 93-97 owner, and that is a system that will easilly handle the rigors of 12-15,000 miles a year, in a true daily driver.... one that is routinely driven in inclement weather, goes through car washes, etc.

My preference for a daily driver would be to get away from the Opti all together. Or, to have a much more robust housing for the Opti. I would think a case with better seals - both external, and internal between high voltage and optical sections - and a true roller bearing in place of the cheapie friction bearing would go a long way to solving the problems.

When the Opti system was introduced, GM made a lot out of the improved accuracy of the ignition timing and the benefits of reduced spark scatter on reducing emissions. They published SAE papers on the system. The value is there... the concept was not all that bad, its just the "execution" that sucked.... using cheap materials, and a questionable location.

I wonder if the Chrysler/Mitsubishi 3.0L V6's from the late 1980's suffered the same fate as the LT1. They used the same concept.... they just had the common sense to leave the system in the "conventional" location on the top of the engine. I suspect GM simply copied the concept, and then screwed it up with location of the unit. But if you think about it, eliminating the gear drive of a conventional distributor eliminates one more source of timing "slop". The fact that the optical sensor carries the Mitsubishi 3-diamond logo would tned to confirm it is no an "original" GM thought.

Nuke:

I guess I misunderstood your original post... I didn't realize you were starting with the premise that the optical signal from the Opti would still be used. And to clarify, the pulse data from the Opti is used by the PCM to develop the ignition and injection timing... there is no direct connection from the Opti to either the fuel or ignition system.... it is simply providing cam and (psuedo) crank position info. If you think about it, as good as the cam position data is, the crank position data is sort of weak, in that the slack of the timing set is in between.

Fred


[This message has been edited by Injuneer 94FormM6 (edited June 04, 2002).]

 

Ryan, did you actually read the thread in the above link? Apparently not. Check my post on page 2. Don't really understand what your dilemma is. It's only $400 plus coils and coil mounting on valve covers preferably. If you want/need details, email me.

------------------
I'll be back

 

From your referenced post:

So, what is the "setup"? Does it work with the "oem pcm" or doesn't it? Ryan is looking for something that works with the stock pcm, not a FAST or a MoTeC (big $$$$$).

Fred

 

Arnie:

Sorry for my ignorance. I have 10 of the $400 setups you are talking about sold. When can you ship?

 

Goal:
1.Keep the optispark high and low resolution signals going to PCM.
2.Remove the high voltage parts of the optispark, the factory coil, and ignition coil module.
3.Use the ignition control signal (PCM C2 pin 5)to control the black box's timing for the each cylinder.
4.The black box will have drivers for the 8 coils it provides primary voltage to.
5.And possibly need a way of identifying which coil to fire.(injector signals)

Questions:
1.How can the black box know which of the 8 coils to fire using the PCM?
2.Can it decide which coil to fire with just the information from the ignition control signal?
3.Could the fuel injector signals provide the black box with the signal needed to know which coil to fire and then use the ignition control signal to fire the coil at the correct time?

Conclusion: If it would be possible to use the ignition control signal and fuel injector signals, from the PCM, to make a decision in a black box. Then decide which coil to fire and when to fire it. We could have a reliable system. Also a new sealed housing for the optispark's reader head and encoder disk would be nice too. I think the electronics of the black box would not bad at all.

I believe this is about the same as Nuke's idea earlier in the post. I hope someone can answer my questions. Thanks for your time.