If I remember correctly, and I haven't read this SFB rules for about a week now, the explosion value of a ship was dependant of the remaining warp, ,AWR, APR and certain weapons system remaining on the exploding ship. Basically pushing the self destrct buttom makes a bigger bang with an intact ship than a chewed up one.
The damage is halfed per surrounding hex it spreads into (odd numbers round down) and it divides by half as the blast radius spreads until disipated by distance.
The biggest bangs are minelayers which have been used as "suicide truck" ships when attcking enemy starbases. A Klingon K-LMS took out more than 50% of a Fed F-BS in a convention game by self nuking at point balnk range!!
There is still a lot of bizare and ingeuineously cunning tactics that are possible in SFB but can't be used in SFC yet.
Another favourite tactic, taking advantage of the explosive force rules, is to remote control a mine sweeper shuttle loaded with two mines and fly it into the enemy's shields for a greater effect than suicide shuttles.
I've always thought taht SFC has always missed out by not including mine sweepers, MSB boxes on ships, using Special Sensors to attempt to detonate nearby mines (which is another function of scouts in battle fleets), and certain other SFB game features.
SFC has always had about 70% of the total SFB game and some of the missing 30% is core to the SFB game.
SFB does allow for more cunning and devious plans than SFC.
However, what it does use is true to the rules.
I use the SFB Volume.III. damage repair power cost tables to plan out the repair order in SFC games. Certain things cost a lot of power to fix and the most expensive is any Plasma Torpedo Launchers at 10 points of power a throw. If you can spare only 1 point of power per turn, it will take 10 turnas to fix!!
Having the SFB tables to hand does give one a bit of an advantage against other players in games.
If you want a proper understanding as to what is going on in the game and how it runs, obtain the rules and all will be explained.