If you use the SCT XCal2 and LiveLink for datalogging, make sure you use a decent laptop. I had an IBM with a 750MHz P3 and 256M of RAM and the datalogging was VERY slow and I couldn't collect more than a few parameters. I bought a new Dell that is much more powerful and it made a world of difference. I really like to datalog with the SCT because it can get any OBD2 parameter, basically any parameter that the ECU sees.
One thing I noticed though is that when datalogging with the SCT the information is not synchronized well. It would be different if each message going to the ECU had a time stamp on it and it could be aligned properly but that doesn't happen. Instead the messages come back staggered a little and you'll see things like throttle goes closed but RPM is still increasing and maybe A/F doesn't drop for a little after that.
I datalog with an Innovate setup. It is MUCH more expensive but grabs the data in real time. It is not near as easy or flexible either. I log A/F, RPM, IAT, MAF Voltage, IDC and vacuum/boost. That wasn't too bad and can get me most of what I need. The log is real-time too. When I let off the throttle, RPM drops immediately and the corresponding A/F change, boost, etc. It is very difficult to get it to log timing though and the SCT is VERY easy to grab lots of other data like coolant temps and other things. -Joe
