Corner Worker

Here is an update on the process as of today. The stock opti gave up the will to live, which has forced my hand at doing this now. So I have discovered that the 727ecm has the same internals as the 730ecm, but uses the same weather tight connectors as the 93lt1. I also have built a crank trigger wheel by hand. I still need to build a bracket to hold the crank sensors, pick up a prominator, and repin everything. Then the tuning begins. Here are a few pics of the wheel and the plugging of the opti hole in the timing cover....updates soon to follow....

Z28ricer

EFI Connection - Coil per Cylinder

Saves a bit of work, uses a better pcm.

???

and i'm sure i left out some odds and ends. don't know the price of all those things off hand, but if i had to guess i'd say over 1000$


running a old school 727

tunerpro $free
prominator $250ish(on the fly tuning. much cheaper ways to do it)
ecm 30$ at junkyard(cal pack will be the hardest part. but i have one he can borrow to get it running)
all the coil pack stuff. he already has, i believe it was 25$ ish
the crank wheel. he made himself with no outlay of cash.

in the end, you end up with full closed loop wideband control with a true target A/F table. none of that 14.7 crap. stock drivablity because the code came from stock gm turbo cars, just expanded to use a 3bar instead of a 2 bar and added the extra tables for wideband input. which even the ls1 pcm can't do. i've also found that targeting my car to run 13.0ish at part throttle and 16ish at cruise, makes for a nicer feeling motor and the same mpg as targeting 14.7 for everything other than WOT like stock ecm's have to because of cats and stock o2's.

over all its a 1/4 of the price and a very cool/fun to do project that deff doesn't follow the normal bs car crafting has turned into over the years.


oh and if he would run the 749 ecm with a few jumper mods it will run low Z injectors. which are cheaper and much better at flowing big numbers while idling cleanly, the boosted apps need. but i think he wants to sort it out first on the stock stuff. then go from there. thats why the 727 ecm.

Corner Worker

I absolutely plan on using the 749ecm. I just have no basis for what VE tables this lt1 motor is going to want. I might actually use ???'s 730 ecm to get it running, then go right to the 749 instead of the 727. I bought the coil packs and crank sensors for $30, plug wires were $35, the ecm (749 or 727) is $40, mem cals are going for about $40, prominator is $250, and the crank trigger wheel and brackets for sensors has maybe $10 in material. If you factor in another $100 in BS, thats only $465....which is barely more than a new optispark. The LS1 software is nice, but its really underdeveloped compared to the code 59 hack. If this is all to much to believe or understand, im sorry. It was never meant to be that way. I just really dislike the opti, and thought it was a good place to do a proof of theory test.

Corner Worker

update....the crank trigger wheel is finally finished. I did the final clocking in relation to the crank today, made some spacers for the bolts, and did a final true in on a lath for the outer edge. The crank sensor(s) bracket is also made. I will make a final piece that is more profiled for a nice finished look soon. I have the coil packs mounted, and plug wires made. I just need to dive into the wiring process. I have found a mitchell wiring diagram of the N* stuff. Just need to get one for the 1993 LT1 and start laying it out. As every project, a thousand other things have popped up and kept me away from the car. I plan on having the car running in 1 month. hope to be fully tuned and beating on it in 2 months. blah

LS1COUPE

Nice work as always Tom. If you need wiring diagrams let me know, i can print them off ******* at work.

Corner Worker

Thanks Rich....I will be bothering you soon.

LS1COUPE

No problem.

Where did the ****** come from?

GOLD_98_T/A

got a crank...actually whole block up for sale..its cheap

Corner Worker

um........dont need a crank. I made the wheel by hand. thanks anyway.