Originally posted by doctorsohc
Compression ratios alone do not dictate which octane of gas to run, timing has also a lot to do with it. Stock timing curves for a D16Z6 are fairly aggressive, they also run very lean in the midrange RPMs in order to get good mileage (15.5 to 1 under light cruise). You can safely run a D16Z6 with regular and the timing bumped back a few degrees, but it's not going to run close to the way it can. I do agree that you should run the lowest octane gas that your car can handle without pinging - running premium in cars designed for regular usually carbons up the engine quite a bit.
In another thread, you said you had some 'other' ECU program. This most likely advances timing and adds fuel which will require the premium.
A stock/lightly modded D16 needs nothing more than regular. You must have the wrong manual for your car because I know the sohc does not need premium.