iv just finished runing in my s2 engine so iv turned the boost up from 10 psi to about 14 but it dont feel any quicker,feels like there is bit off a missfire on boost,its got new plugs/leads/filters.etc runs ok off boost n up to 10psi, cheers

 

did you solely just increase the boost?

 

it might be not be fueling enough for 14psi mate- get it checked and turn it down till u do