Dwell is the duration of the points being open. It's a term you don't hear much anymore, as it only applies to points. Electronic ignition is triggered by an instantaneous signal from either a Hall effect, optical, or other sensor in the distributor, or a crankshaft position sensor.

On the 89 and later B230F , base timing is fixed, nonadjustable. The knock sensor will allow more timing advance with higher octane fuels, so if your ethanol blend has a higher octane than regular gas, it will adjust automatically. However, these engines were designed to run on 87 octane, so higher grades offer little or no benefit. Turbos, on the other hand, will run noticeably stronger on premium.