I honestly don't know much about the stock ECU -- does the stock ECU have the ability to log all engine parameters at 100Hz so they can be analyzed later via software?
Rob
Rob- the stock ECU doesn't have internal memory for logging in the same fashion our EFIs do. You can log somewhere is the neighborhood of 10-50hz (speed depends on a few things in the laptop scenario) with a laptop connected or use an AIM device or similar on the CANBUS to log. That's plenty fast for tuning the car. 100hz is for logging chassis movement. Very few things on the the engine need 100hz logging. As you know, the EFI logger would be full in just a half dozen minutes logging all the needed motor channels at 100hz... If you're referring to your experience diagnosing crank or sync errors on the EFI, those don't exist on the OE ECU. The OE ECU picks up both peaks and valleys of the crank signal. Quite a bit different deal. The ability to log is there and perfectly adequate for tuning with MUCH faster data speeds than traditional OBD...
Cons of the stock ECU for racing, that are just off the hip:
-It doesn't daisy-chain to external telemetry devices with PnP ease like a Motec or EFI does.
-It doesn't utilize internal memory in the same way the EFI does (although, the internal EFI memory is really just a quick diagnostic tool. You still use external loggers for heavy lifting).
-It doesn't have the same external inputs for oil and fuel pressure engine protection (yet

)
-In some respects, it's more complicated to tune, as the Stock ECU has dozens more tables and scalars available to tweak than the EFI/Motec. (assuming you didn't have a decent base map, which of course everyone has a decent base map in the ECU)
Pros of the stock ECU for racing:
-It's MAF based and consequently runs perfectly in a wider variety of climate conditions than the EFI/Motec without tinkering with the tune
-It's perfectly configured to the car's hardware as it comes from the factory
-It's already plugged in leaving dollars left over for other mods on the car (level 2 editor and you're done for full access)
-In some respects, it easier to tune, because all those tables I mentioned the stock ECU has that aftermarket ones don't have are already configured for the most part. The MAF sensor makes life pretty easy and it compensates nicely for modifications that impact the VE of the motor without even touching the tune.
-Much more complete diagnostic error codes. When something is wrong, there's a code telling you what's up.
-It has some engine protection features the EFI doesn't (misfire, cam/crank timing/ sensor failures, etc).
I have my track car setup to run the stock ECU and the EFI, as my EFI is attached to a PnP box. I will toggle between the two of them before deciding which one to keep in the car... We've fit over 100 Lotus cars with EFIs and have been pretty happy with them. Figured I'd never go back to the stock ECU on my track car (I obviously prefer the stock ECU for street or mixed use cars). Although the stock ECU technology has progressed far enough that I have to take another look at it even on a dedicated track car...
-PV