94 LT1 massive re-program- Where to start?

[Sleeperwagon]

Apologies in advance for the long-winded post-

Well, I may have bitten off more than I can chew. I own a '94 Buick Estate Wagon, and have limited experience with the ECM. I have done some basic changes, ie EGR delete, rear end gearing and tire correction change, max speed fuel cutoff, etc. But then, I lost oil pressure at the drag strip. That led to a rebuild, which led to a stroker crank, which led to a huge cam, which led to a port nitrous kit, which led to a T-56 conversion, and on and on and on. It may be easier to list the parts that haven't changed. But here I am, with the engine back in, transmission installed, and almost ready to fire it up. EXCEPT, I am certain that it won't even come close to running with the tune that was in it when I parked it. I bought 4 books on EFI systems (Both books by Banish, one by Strader, and one by Cramer and Hoffman) and while I now have a fairly thorough understanding of how the systems work in general, there wasn't much specific on early OBD1 stuff. Here is a basic list of the things I have to account for. I'm sure I have forgotten a few and will need to update as I go-

displacement increased from 350 to 383
11.5:1 compression
ZZ409 cam
heavily ported iron heads
Long tube headers
port matched intake
1.6 roller rockers
44lb/hr Accel injectors
smog pump delete
EGR delete
OEM throttle body bored to 54mm
F-body MAF
Converted to dual electric fans
T-56 trans from 96 camaro
3.73 gears
3inch x-pipe to dual 2-1/2inch exhaust
Aftermarket coil and colder plugs, gapped .035 and electrodes rounded for nitrous

The nitrous system is essentially completely separate from the EFI:
direct port with 8 fuel/nitrous nozzles
Fuel is supplied by a separate electric pump at 7psi from a separate tank
Entire nitrous electrical system is separate. Fuel pressure, nitrous tank pressure and fuel supply safety interlocks incorporated to ensure nitrous supply is interrupted if fuel flow is compromised. Intention is to tune nitrous separately for essentially neutral burn, so any minor rich/lean conditions are within the range of ECM adjustment when nitrous is engaged.

Where to start? I know data-logging will be necessary to get a final tune, but the car has to run first. I have injector specs from Accel, I think I understand how to adjust cylinder volume, injector flow rate and offset. I will need to disable all settings relating to the auto trans. I intend to completely tune the car NA before I ever start messing with the nitrous system. Should I try to find a BIN from an f-body manual trans car that has been stroked as a starting point, or make massive changes to my existing BIN? I kinda feel a little overwhelmed and I'm scared to death of killing what has now become an extremely expensive engine before it's even broken in. Any advice is very much appreciated!

Tom

[steveo]

i’d try to stick with the b body bin i think your bbody dash candy might misbehave otherwise. there are lots of bins on my site if you want to compare
unset the auto trans flag and if any dtcs show up deal with that after
copy the speedometer settings from an fbody 3.73 bin
input your new injector flow rate (and offsets if you have them)
copy the fbody maf tables
increase idle speed targets and add a bit of closed tps timing advance
you’ll probably have to enlarge the idle bypass hole in the throttle body
get eehack running and if it has trouble idling you can play around with timing and targets until you fund out what it wants
i’m sure it’ll run well enough to not blow up while you break it in and you can fine tune from there. you can get a maf table dialed in really quickly once you start logging.

[Sleeperwagon]

Thank you sir! I have eehack on my laptop but haven't tried interfacing with the car yet. One thing I noticed on the Accel injector specs sheet VS what I see on tunercats is that the factory chart has a very wide range of voltages, but the new injectors tables only go from 8 to 16 volts. Since the new offsets are much higher (in some spots nearly double the OEM injectors), should I just estimate the extended ranges of the table, knowing the engine should never go there? I'm not sure if the car uses finite points from the table or if the computer uses a continuous curve. If it does and I only replace the 8-16v numbers, then it seems like as it approaches the ends of that range where the table has large shifts back to the factory numbers the curve would be quite inaccurate. Sorry for being uneducated on the actual computer processes at work here.

[Sleeperwagon]

Also, you mention having BINs on your website. I'm starting to make the connection that you are the guy who wrote eehack? What website am I looking for? Thanks!

[steveo]

yeah that’s me

see fbodytech.com bins > factory calibrations

if you post your injector data i can generate a spline and get you a proper lt1 table since the points are almost certainly different

its fine to just guess for values outside 10-15 volts or so as it will run like crap with low voltage no matter what

[Sleeperwagon]

https://documents.holley.com/accel_i...ons_150144.pdf

This is the spec sheet for the injectors I am using

[Sleeperwagon]

Got all the program mods done as suggested other than the offsets. I can possibly approximate the spline using Mastercam (I run a CNC machine shop) and get the numbers I need. One other quick question though- I have seen a few people mention the possibility of bricking the PCM when using eehack to actually re-flash the bin into the car. I still have tunercats from when I was playing with the car before the engine build saga, and used it for all previous bin modifications. Is it safer to just use it for the flash, and then switch to eehack for the datalogging part? I failed to mention that I installed a wideband o2 sensor with an LC-1 controller before the car was parked, but never got around to wiring it through the A/C pin for data logging. Is there a more elegant way to incorporate the wideband that has cropped up in the 5 years the cart has been collecting dust?

Thanks!