I've never had a degree wheel on an N21 so I can't say for sure but most likely it could stand to open a bit sooner and stay open for while longer as well. Crank timing is kind of trial and error anyway until you find the combo you like. Just don't go more then 1.5mm or so on either side and you wont kill it but without more exhaust duration to go with it you may not see much of a gain. Then again, it make it SCREAM, haha