Sweet!

Well I have the first real test for brushless rusty tomorrow, after school tomorrow at work a fellow employee wants to race rusty with his Jato. I couldn't let everyone down (I'm the local "hero" with rusty, long story) and since everyone wants me to wipe the floor with his stock jato I soldered up some 9 cell packs for some short runs. Man is this thing fast, I don't know if it'll hang w/ a Jato but it'll be close enough where my driving skills will prevail over his. One thing that I did notice though was that going from 8 cells to 9 cells I have lost run time by about 40-50%.
I'm using the same cells but now in a 9 cell configuration, any ideas?
I was thinking that it might be that I need to run a reciever pack now but I'm not sure, any help would be appreciated. Thanks!