NEED HELP WITH JGR......

Hi guys.
I have some very important questions. Iam totaly new to the Warez scen of DC. And iam about to burn my very first DC game. Now the problem is..
In the NFO to Jet grind radio it says its ona 74 min cd. Alright.
I unpack the game to cdi format(diskjuggler) and cheked hoe big it was. and my cdi is 680 meg? Now a 74 min cd can only have 650 meg totaly. Now this cant be right???
Or does th cdi format do anything special when you burn it??
Really i need some help here. And also do i need to rename the cdi to any special name, so it will work as a DC game when its burned? The current name is e-jgr.cdi

PLEASE PLEASE
I need your help.

Thank you.