Rode without the Q4 insert today and question about the PC4

Megabomb+Q4 without insert+PCV (map: Leo,no air lid,no spark arrester) = THERE IS THE POWER

Without ear plugs it would have been intolerable, and it sounded like a helicopter at stop lights (actually seemed louder at idle), but it made me realize these FMF systems are really designed to be run unplugged. There was enough lowend power to tiptoe through neighborhoods at low rpm, and at mid/hi revs it had a deeper smoother sound, although it was definitely louder overall. Much better power everywhere. I could see myself using this setup on street-only rides. Much too loud for the woods though :(

Powercore 4 users: how is the power/sound with the smaller diameter insert 1-1/8"? I am thinking that might be my quiet performance solution.

I don't know what diameter a PC4 is stock, but it is very LOUD. Way too loud for my tastes. Mine came with one and after riding it home I immediately went back to stock. I noticed a difference in power but the noise level is just unacceptable in my opinion, way too annoying for me and other people on-road or off-road.

I put the smaller diameter insert into the Q4 and it definitely quieted it down a lot, at the expense of some higher rpm throttle response/power. I'm thinking the smaller insert could also quiet down the PC4 to an acceptable level, but maintain just a touch more power than the Q4 did with the same insert. But then again, maybe I t is just too loud either way. I am a fan of quiet bikes, but with this 250 it's very tempting to milk every possible hp.

I agree. I liked the extra power but could NOT stand the noise level. I did not think of different cores until I had already sold it haha.