Programmable Delco Ignition Module

[Xfirez51]

It should be possible to replace the lt-5 module entirely, I have not tried this though as they are not very common in oz!

Ok. I am positive we can find people here in the States to do exactly that. I am a board member on the
ZR-1.net Registry. If this can be made to work, it would alleviate a critical issue in maintaining our cars.
The stock ICM is a very robust unit. Mil spec. But it's also 25 years old and cannot be repaired.
Please pm or email me if you'd like to move this forward. It would make a great topic of discussion during our 25th Anniversary Gathering at the National Corvette Museum here in Bowling Green, Ky.

[VL400]

Will go over the info you sent awhile back and confirm a few things, and will setup the test bench to suit what it should be like. There is a fault indicator that your original module sends back to the PCM, the GP output from my module can be used for this - still needs to be coded in but can be done at any point with a firmware update.

[Xfirez51]

If I can provide further info let me know.

[Xfirez51]

VL,

Her's a DB link allowing access to the DIS module documentation I have. Not sure if I had shared this with you before or not. It should help in clearing up questions you may have.

https://www.dropbox.com/s/mknilo4t50kt1 ... e.pdf?dl=0

[VL400]

Thanks! Thats very helpful with a heap of detail.

There is really only the fault output that needs to be coded, the output from my hardware will work fine based on the info in the PDF and I already count/check the EST and ref pulses so have a fault counter for EST missing errors. Couple of lines of code and that can be used to control a fault output.

Aside from that it should currently do everything that the LT5 needs Have only ran the extra tooth trigger on one engine so that will be a bit of a test.

You will need to either change to LS1/2/7/9 etc type coils or run a 4 channel bosch ignitor (part number 0 227 100 211) to keep the existing coil base.

[Xfirez51]

VL,

I am actually thinking of using pencil coils that would fit in the spark plug well. Would it be possible to fire coils individually rather than waste spark mode?

[VL400]

Going through that PDF more carefully your ign module is different to most others in that the reference angle is 6deg BTDC? In all the aussie setups and other extra tooth triggers its always greater than the maximum spark advance (ie around 60 or 70 deg). Can you run a 51 deg ref angle by editing the ECU bin/cal?

But for your question, seq is possible with a cam sensor in addition to the crank trigger and a firmware change (has not been added for extra tooth triggers as there has been no one wanting to run that). Otherwise can run wasted spark on the COPs if they can handle the duty cycle. Dwell becomes REALLY critical on some COPs, which during cranking and module mode will possibly damage them - my module does the same as your LT5 module as described in the Open-Loop Dwell section of the PDF you linked.

The dwell time also becomes a problem trying to command the 1.5ms dwell some COPs require. As my module, and your LT5 module, have no idea of when the ECU will be commanding spark advance it can only go off some prediction based on the last delivered times. At idle RPMs a 1 degree change in delivered spark is 0.25ms. If the ECU advances spark by 3 deg from the last event thats 0.7ms gone, if the engine RPM also accelerates by only 20RPM since the last reference pulse thats another 0.6ms gone. Your 1.5ms of dwell is now 0.2 and a misfire happens for that event. Not a problem when its calculated in the ECU as you can correct for the spark advance change, but very difficult outside the ECU.

[robertisaar]

I'm bored and this is something I haven't calculated before and seems relevant, so:

Corvette C6 ZR1 0-60MPH is 3.3 seconds, redline is 7,000RPM, top speed in 1st gear is ~66MPH(they're certainly quick).

assuming a launch at 2000 RPM(and the clutch just gets dumped and the tires spin until they catch at the 19MPH they would be at 2000RPM)and linear acceleration, 3.3 seconds after launching, 6,363.6 RPM is reached(and 60MPH), so 4,363.6 RPM increase over 3.3 seconds.

1,322.3RPM(22.038 revs/second) increase per second, looking at 2000RPM(33.333 revs/second), the crank should go from one revolution in 30mSec(2,000RPM) to one revolution in 29.4mSec(2,039.7RPM), so .6mSec faster per revolution. being an 8 cylinder engine, that is .15mSec faster per firing event.

did I screw up the math somewhere along the way? .15mSec of possible error due to crank acceleration per firing event doesn't seem all that bad to me... at the 7,000RPM redline, that would be the crank spinning 6.3 degrees past a desired spark point while maintaining a fixed amount of dwell.

I don't know how aggressive of crank acceleration your code will try to account for, but I would say within 2* at redline in one of the more extreme production cars available would make most people pretty happy..... that would have to be pretty damn competitive with anything that doesn't have the PCM directly controlling coils.

[Xfirez51]

I assume the 51* Ref is the base timing. I know I can change that in the bin. Not sure how that would work and synch w the injector timing.

Here's an example of the type coils I was considering. Getting an inoperative one to test for fit.

http://www.weaponxperformance.com/techn ... l_Coil.jpg

[Xfirez51]

VL,

Reading the documentation, it appears that the Reference Signal is 51*. Take a look on page 4-3. Am I reading it correctly?