darkside: because the alky provides some amount of btu's in addition to the gasolline you should be prepared to make fueling adjustments.
How much of an adjustment, and, in what direction, is contingent upon how much alcohol (by percentage of total fueling) you are introducing, and other factors such as boost level, chip, injectors, etc.
Black6pack pointed out that raising boost has the same effect as leaning out the overall fuel. This is because you are adding more air molecules but fuel is staying constant.
This is how many people "tune" for optimum O2's and/or EGT. Waiting until you get knock can be somewhat misleading due to the many variables surrounding the creation of knock. If you're using a low timing chip you may never see knock while burning an exhaust valve. That's an extreme example tho, and you would see this as high egts.
This brings me to my last point. IMWO if you wanna 'play' with these engines then you should spend a few more dollars on some quality tools; A fuel pressure gauge is an absolute must! A scan tool in next then an egt meter. Using all of these will get you running safely. Good for you if you already have these. Good luck.
