Originally posted by bruce
I did ask given identical timing and PWs which was better, it's in the opening sentence.
Okay, I maintain that at a given pulse width and amount of timing at a given engine condition, I can build a hardwired electronic circuit that will have the same electrical characteristics as a stock ECM or an aftermarket ECM. A couple of 555's and some basic glue logic. Or, for more accuracy, an oscillator and some
counters instead of the 555's. Getting to the right pulse width and timing is a different issue.
I think everybody tried to ignore the simplistic phraseology of the initial statement here and tried to address the intent clarified in the text following.
What aftermarket advantages have we seen mentioned so far in this thread?
1. -WB feedback.
2. -3,4, and 5 BAR boost sensing.
3. -Easy data logging.
4. -Overlay a run on VE tables.
5. -Real time programming/updating no burning chips.
6. -Support from the ECM manufacturer.
7. -All this integrated in a single package.
True, with enough cables, switching back and forth from this package to that one, you can approximate most of this using an OEM ECM and a bunch of aftermarket stuff. Integrating data logs
from multiple sources - assuming you're logging a WB O2. A Romulator to avoid burning chips. The learning curve for that stuff is a lot higher. All to save maybe $500.
Of course, you can't get manufacturer (GM) support for the OEM ECM either.
BTW, someone should have pointed out that the WB feedback is a redundant safety feature in the FAST. The primary settings are from the tables and the WB correction is limited to a use-specified percentage (in case the WB dies). This is a great feature (I wish I had) not something to be discounted as a single point of failure. I think the Gen vii+ was mentioned to do something similiar.
Something that hasn't been mentioned is that the aftermarket ECMs offer some interfaces to other aftermarket systems (NOS, two-step, shift lights, ign systems, etc) that aren't really there on the stock ECM. If you want that feature, you can add other independent boxes to monitor things, and maybe a code patch, but the FAST and DFI's have controllable nterfaces built in. Incidentally, one of Bruce's responses was slightly in error. My old DFI has an interface I used for TCC before I went to a non-lockup converter. It wasn't as good as the stock ECM TCC control, but it did work. From what I understand, the new stuff
is better. The one I have missed is the AC input for stalling control. I have heard that the Gen vii+ does monitor this.
All the above is factual, not opinions. These are differences between stock OEM and aftermarket ECM's. I tried to get Bruce to give us real specs for the stock ECM. He didn't want to play. I provided info for the aftermarket ECM I have used. Steve Y gave us the only other performance data. Bruce you haven't contributed any. You always harp on people not answering your
questions, but you consistently ignore specific questions directed to you.
Incidentally, I got curious. That 0.25 degree and 0.3 degree of timing adjustment? They're are talking about .003 in of piston travel in the 20* BTDC area. I think most of us will accept that
vibrations in the engine can make 3 thousandth of an inch of jitter in a piston. Of course, we won't see all the jitter that has been alluded to. The Buick crankshaft sensor only produces
3 pulses per revolution and they are all lined up with piston activity. BTW, this jitter isn't really making the crankshaft
jerk back and forth. It doesn't stop and go backwards. It is small uneven variations in the RPM. When you use a synchronous strobe light it sure looks like it's jerking back and forth though..