OK so i have about 10-15 flights on my big pink that flys OK with my ryobi 31 and a 16X12 apc but today one of my muffler bolts came lose allowing my muffler to swing to the side and run open head wow!!!! what a difference that thing was screaming how bad is it to run muffler-less? when i landed she wasn't that hot. but i also know back pressure comes into play so how can i keep her ruining that good without hurting her ? i have a stock muffler with the guts taken out.