Originally Posted by arlockstedt
just found this -
The Arrington 90mm drive-by-wire Throttle Body - 819cfm at Wide Open Throttle a full 178cfm over a stock 80mm throttle body..
stock = 641 / 1.5 = up to 427hp - 22% drive train loss = 333rwhp
90mm = 819 / 1.5 = up to 546hp - 22% drive train loss = 426rwhp
so an 85mm tb would be a great half way point and should make a difference if you have a bunch of bolt ons helping air in and air out.....
I sure hope those numbers are wrong becuase they are terrible if they are and Ram seriously needs to fix the design. the 2012 mustang 80mm tb is rated at 913cfm and the 90mm is rated at 1132cfm.
a little technical but here is pretty good write up wrt to tb size selection