put on a smaller sc pulley and now i make less boost?

got my afm mr freeze boost cooler kit in and pured in 50/50 methanol/distilled water. it make take advantage of the cooler intake charge i took off my 3" pulley and put on a 2.75" i used to get 9psi of boost no i get 4psi. what the hell happened? i also lost hp. i can see the hp loss because im not done tuning, probably have to have the dyno tuner do it cause i have the fp set at 42psi getting a 10.5:1 afr which is close to what my tuner set the afr to when i ran the 3" pulley so afr hasnt changed much but i lost boost and power.(he had it set to 10:1 for some conservative reason) the belt is tight and i dont hear any slipping. why did i loose boost with a smaller pulley?

im checked all the clamps, all are tight.
Rick 91GT, i dont see any belt powder and i dont hear any slipping. and if it was slipping it would have to be slipping like crazy to get that low of a boost (4psi with a pulley that should get 12). yes i am spraying the mr. freeze. should i try disconnecting it and going from there?
i have a longer belt which would cause the belt to rap further around the sc pulley.....should i try putting that one on?

ok just went to the gas station....that was an excuse to go for a drive. i tried flooring it. uggh the belt IS squeeling. horribly! sounds like a pig being led to slauter. and when i got home i could smell burning rubber. i have a longer belt (the belt i used for my 3" pulley) i know it fits with the 2.75" pulley ive already tried. if i run the longer belt the center of the belt (the space between the 2 pulleys) will be pushed in further. the longer belt will cause the belt to almost touch itself in the middle as it goes around the tensioner but it doesnt touch and this would get me maybe .25" more surface coverage around the sc pulley. you think that will help? does what i just said make any sense?
what else can i do, i cant afford a 10 rib pulley set

i plan to go to the dyno tuner in about 2 weeks. grand opening of a new one offering 3 pulls for $45. i have to find out if they can do anything with the custom chip i already have though.