Has anyone converted an opti system to a distributer? Could you change from a sequential to a batch fire so you wouldn't need an opti to fire the injectors? Just testing my options.....

Clyde

 

I don't think anyone has switched to a distrbutor myself, I could be wrong though. I am not sure it can be done b/c the computer gets some kind of signal from the opti to do something with. I don't know too much about it as you can tell, just from what i've read.
If you're looking to switch to something better, DTE looks to have something better than the stock unit.
http://www.dynotech-eng.com/dynaspark.htm
Not sure if anyone is using it yet or not and can tell you how good it is but i know the price is a little high for ME right now.
I think some other guys put together a conversion kit to switch to the ls1 style setup. (coil for each cyl) You'll have to quick search those threads though b/c it's been a while since i've seen them.

 

Clyde,

I am in the middle of a project (well actually almost done) with my 69 Camaro convertible. We are putting an LT1 from a 94 Bird into this car. We have gotten rid of the Opti and are using a probillet distributor. We have done many other mods as well.

My LT1 project

Take a look at the link and see if this is any help to you. I am not a technically oriented person but I can try and answer your questions concerning this engine.

Good luck with your project

bob spears

 

Hey that looks good.. What kind of intake is that? Also what are you using for the I think it's called the low pulse signal (I dunno haha) that the opti was suppose to send to the pcm?

 

nice.

 

Ricochet,

The intake is an ACCEL SuperRam Gen VII EFI. I think it is one of ten or eleven ever made for the LT1. As to your question about the signal from the OPTI to the PCM my answer is "you got me?" The old PCM, in fact the whole original wiring harness, is gone. It has been replaced by the ACCEL computer and harness. I am not exactly sure how everything talks to each other but it must work because it started beautifully yesterday for the first time. Thanks for the kind words about the car. I hope to be on the road next week.

cheers

bob spears

 

What he is talking about is only a problem when you try to retain the stock LT1 PCM to control an LT1 engine equipped with a "conventional" distributor, or are trying to keep an LT1 with an aftermarket engine management computer in a street driven 4th Gen.

The stock PCM will not function without the low resolution pulse from the OptiSpark - a series of 8 unequal length pulses identifying the specific position of each piston, required for sequential fuel injection. If the stock PCM can not find the low resolution pulse for 2 crank revs, it shuts down the fuel system, including the pump and injectors.

If you are running completely on an ACCEL/DFI, and using a mechanical speedo, or don't need a speedo because its a "track-only" car, you don't need to retain the stock PCM. If you want to retain the stock 4th Gen speedo, retain the PASS-key system, and run the fuel pump off the stock PCM, you have to retain the ability to supply the low resolution pulse to the stock PCM. This could be achieved by using the crank trigger and "Opti-Eliminator" chip from Electromotive (they only made about 20 of them so they are hard to find), or keep the Opti and just use it to supply the low res signal - that's they way I do it.

Switching to batch fire, rather than sequential makes life easier, but it isn't necessary, since the cam position can be marked with a magnet on the cam sprocket and a pickup on the timing cover, which has been demonstrated in another thread on this forum. But that would involve an aftermarket computer as well.

 

That's a bit high for me too, especially considering it's only got a 12 month, 15k mile limited warranty. At least you can get remanufactered opti's from Autozone for a little over $100 after exchange, that carry a lifetime, unlimited mileage warranty.

 

Here is a link to a video of the first dyno fun of this beast. 340 RWHP and 500 RW lb/ft of torque and still some tuning to do.

video of dyno run

cheers and have a nice weekend

bob spears

 

What is the RPM limit of the factory PCM and opti? I want to shift at 7500 RPM


David

 

7000 RPM limit for stock PCM

 

You can fit the opti internals into an HEI distributor, and it's fairly easy to pull the oil pump drive out of the block and drill the back of the manifold for a distributor. It doesn't leave any room for an EGR though...

 

WS-6 have you got pictures of this conversion?

 

Well, yes and no. Yes, I took pictures when I did it, no, I haven’t been able to find them (Lost the harddrive, and they should be on a backup but haven’t been able to find them). We did it when swapping a ‘vette LT1 into an ’83 Z28 with an ATI blower. I do have pictures of someone else’s conversion but I promised them that I wouldn’t show them to anyone else, I believe that he’s going to market it…

 

Chris S here in Chicago did this conversion about two years ago.

Page him in the LT1 section of www.ls1tech.com, he posts at "INURDDRMZ" and the car has gone 9.4@145mph and should go 155mph at some point.