The Machs have a higher rpm clutch engagement, mainly for the launch control, then the other 900 Turbo R's. The Machs have different primary ramps. The Machs have 897 ramps, all other 900 Turbo R's have 880 ramps, again for the launch control. The surging, Turbo flutter is on all the 900 R's.. Imo, ride it...Also this 900 Turbo R motor 'loads' up at lower rpm alot more then previous 900 T's... All 900 Turbo R motors are the same..My 2022 Renny XRS 900T R does the same thing @oldslowsledder, and I've witness the ones I've passed and crossed paths with, do the same..Machs, XRS AND X's.