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Originally Posted by 8upZR1
I guess I can bring myself to understand your point, however, when I think of the LT5 ECM the only thing in my brain is this:
The LT5 came out in 90, ergo the ECM was engineered in probably '84 maybe '85. In 84/85 I was playing Comodor 64, or 8 bit Nintendo. Now its 2008 and I have out grown a comodor 64, and 8 bit Nintendo, and LT5 ECM.
I remember reading somewhere in the registry on a tech page that the early ECM can only resolve RPMs in 250 rpm increments. Like 0-250-500-750-1000. The newer LT5's supposedly read 20 RPM increments. Thats quite an improvement over 250, but is complete shite compared to the resolution of a F.A.S.T. ACCEL, BIG STUFF, MOTEC, etc. The engineers at GM really aren't to blame as they were working with shite to begin with. Even if its original, you cannot possibly argue that LT5 ECM holds a candle to modern EFI controls with modern microprocessors. Why defile your LT5 engine with the original ECM? It barely works, it breaks all the time, parts are impossible to find, it needs all sorts of $$$ ancillary equipment (IGN module), and is totally outdated. Take your LT5 ECM and put it in the box next to your Nintendo. Maybe in 30 years you can whip em out and let the greatgrandchildren learn about how hard we had it in our youth.
If you EBAY your ECM, PROM, IGN module, spare IGN module #1, spare IGN module #2, plug wires, coils, mount, wiring harness, secondary relays, etc. you will have plenty of cash for a F.A.S.T. + money left over to buy drugs. It makes sense to me at least.
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Actually, the resolution on the LT-5 code is in 100rpm increments. Not sure where you read that its 250. Early C3 ECM like the 7747 had resolution in 400rpm increments. The higher rpm ranges, ie over 2000 rpm, go to 200rpm and then 400 up to 7000rpm. That's for the VE and SA tables. In most cases the aftermarket stuff resolution is considerably less granular than the OEM. That's because the AM stuff doesnt't deal with the same constraints the OEM needs to. In addition, there's much more
logic in the OEM cal dealing closed loop controls. Aftermarket stuff is usually more expensive but more rudimentary in its logic. As old as the
LT-5 stuff is, its still pretty good. Its not as much a question of the processor speed but more importantly the software running the motor.