Good question and Blowsion doesn't make that trim system, it's made by Skat-Trak as an accessory for their mag pumps. I would image there would be less restriction without the fins.
yea u would think, but they must do something??
pro tech nozzles do not have fins either:dunno:
the protec maxflow has fins, the older ones that used to be available in a few different bore diameters didn't have them ( thats what mine is and its FINLESS)
I just bored the nozzle to 86.5mm this week but I have yet to try it out.
I also heard that these things have cavitation issues, so I might just keep my raider setup.