I Put together a little site Detailing the process in a step by step Manner.

http://www.speedtoys.com/~bort62/7749/Index.htm

Take a look, I think Ive coverd all the bases pretty soundly.

Hopefully This will encourage more people to Do this incredibly straitforward swap

 

i just finished my new shop and am going to get started on this soon hope it's as easy as it seems
pete

 

This is so interesting,

I wonder how the signal from the opti spark from 92-93 LT1's differ from that of a 90-92 TPI.

I know a few guys who really wish they had 2 bar support.

 

Thats an interesting Idea, Rooster.

The 93 Lt1's used a ECM that was similar to the 7730 in some respects AFAIK... It might be a pretty straitforward process...

 

I wish there was enough room (cowl) to run a regular TPI distributor back there. I don't think there would be any problem then.

Anyone else know? There might not be much difference between the two

 

Workin on it.

It wont plug and play, but as to how much interpretation is nessicary on the part of a third party device is up in the air.

 

What about modifying a opti spark with a HEI pickup? I've got plenty of spare opti sparks, maybe I can shim one up so as that one would fit.

Or maybe someone (who is much more knowledgeable than me) can make a amp or something else that can convert the opti signal.

 

Well, From how Ive come to understand it, It is going to be Nessicary to either

1.) Conver the Opti Wheel to having Windows of Equal Size and Distance...

2.) Devise a Third Party device wich converts the Opti's Signal Into that of a Conventioal HEI.

I personally Vote for #2, But Im No EE and Wouldnt know how to go about such.

 

Hey,

take a look at the DA2+3 code, it has alot in commen with you guys. Its speed density, prom, no electronic transmission, batch fire etc..

I've taken a few opti's apart, theres really not much do them. If someone had some sort of equipment to actually make the metal opti wheel it should be pretty easy

 

got a picture of an opti wheel and some musarements for scalling the measure needs to be very accurate. i have an idea just how feasable ??

 

Sorry no digital camera,

Maybe I'll dig one out tomarrow,

they are around 1.5 inch in diameter with 2 different sized slots (maybe 2mmx1mm). they are made of a very thin piece of metal almost like a foil but thick enought to be rigid.

If you think you can reproduce one? If so i'll mail you just the wheel.

I don't have a blower car but know of especially one guy who would kill for a 2 bar map setup.


You know I was thinking today about those SLP and autometer speedometer calibration boxes. They are just taking the signal and multipling it by a number. I wonder if there can be a way for us to just modify the stock opti signal with either the same or similar "calibration" box.

 

if you truly have a spare opti wheel email me and ill send it to the machinist and see what he cand do.shouldnt be to hard to be honest just punch a few holes in a pice of steel 8 of them and have them evenly spaced. do you have a junk opti setup the whole thing ??i have a better idea just need to see how much room is in there.

 

I should, for a while I had like 8 or 9 of them.

I'm going to check today to make sure none where thrown away by dad.

Send me you mailing address. I would rather just send the wheel because it would be cheaper and easier than for me to go to the post office. Plus too the conversion wheel would have to be the exact same demensions to fit into the opti sensor.

 

quick question is the opti sensor ouput the same wave form and voltage span as a normal hei hall effect ?? yeah ill email you with my mailing then you can send me the poti wheel im not making a promise but ill look into it.

 

I looked at one today. The opti wheel has small slots (too many to count) and a seperate set of slots which are not the same size and roughly 45 degrees apart.

The opti sensor it self has 2 eyes. one to measure the smaller slots and the other to measure the larger. I would think the larger slots may give the computer some reference to where the camshaft is??

they do have a partnumber stamped on them 10470967

I really don't think this wheel can be replicated easy. The slots are very very small way smaller than I remeber.

I think the best solution would be to fit a TPI sensor into the opti spark. Once you remove the opti sensor there is plenty of room to install one. The opti sensor is a little flaky too. Alot of them fail because the wheels like to rust.

 

fyi i dont own a thirdgen gm f body. i was trying to be helpful. if you have a whole opti spark send it my way i think i can fit a trigger of some sort in there.

 

Re-designing the Opti Wheel to position the same windows but at symmtric intervals would probrably be cost-preventative.

However, Fitting a convetional Pickup coil / Reluctor Wheel Intot he Opti might be fairly straitforward. I don't have access to any optisparks to fiddle, however.

 

I took a opti apart, there are a ton of small slits really small. I kinda forgot what one looked like.

I would guess that there must be at least 360 small .5mm by 1.2mm slots. a little more inward there are 4 different shaped slots. two eyes monitor the wheel.

Someone had an interesting Idea of using a crank sensor setup out of a 96-97 for a pickup in a 730/749 setup.. Sounds great but does anyone know if they produce the same signal?

The crank reluctor wheel only has 4 magnets but thats okay the crank turns 1/2 as much as the distributor.

 

sorry I meant twice as much as distributor.. but you guys knew that

 

if you made a new opti wheel with 4 holes 90degrees apart your problem is solved as long as the opti output can trigger an ignition module.

 

The Opti output is 0-5v, so yes it will trigger the ignition module.

Here's a Stupid Question and inferance...

The Opti has a Low res and High Res Signal... Is the low res derived from the larger windows, while the High res stems from the Smaller ?

Would Make sense... Yes im an idiot.

hahaha

So wax the high rest, we don't need it. use the low res signal with a new evenly spaced plate... presto chango your halfway there.

 

I don't want to pursue modifying the stock opti anymore, you praticly got to destroy the wheel to get it off.

Also there are quite a few problems with the opti sensor. If the waterpump was to go bad the weep hole from bearing/seal faliure will get the thing wet and they usually rust soon after.

I've also seen the back seal go bad and coat the wheel with oil.

The magnet reluctor style pickup would be much better as far as durablity oh and considering you can always buy a new pickup. If you destroy an opti sensor your imediately out $270 cost.

 

749 is meant for a distributor that uses a magnetic field for generating the signal, this field strenght varies with rpm so there is a spark latency correction.

Optispark use an optical sensor so there is no latency.

There are 8 signals per dis rev on the low resolution part of the Optispark.

Should be enough hints.....

Yep, a small kludge would go a long way.

 

I think I sort of grasp what your "hinting" at Bruce, but not entirely.

Truth is I am not the person to pioneer this, I just don't know enough about how the whole system works.