Since there seems to be alot of i hate pirates threads, instead of posting this in every thread i come across i'm creating this post as a one stop shop to allievate the pirate timers for those who don't like it.
First off you need to browse to your Sins of the Solar Empire/GameInfo folder.  Next find the file called Gameplay.constants and make a back up copy then open in notepad and search for these lines
firstWarningTime 900   //this is used to determine the very first attack
normalWarningTime 720  //this is used to determine time between attacks after first
minSendRaidTime 30     //this is minimum time to send raid after warning timer
maxSendRaidTime 90     //this is the same as above except it's the maximum time
all values are in seconds.  Hope this helps those of you that hate the pirates.