Originally had B1 30P and heard all the talk about the Hydromotives so had a chance to try a set of 28P. When coming out of the water they blew out a lot. The B1's have never done that. Anyone have any experience with the same thing?

Top speed was about the same but I was on the rev limiters so a taller QIV would get a little better speed but getting on plane so slowly may not be worth it?

my hydros do the same thing. everyone tells me they blow out easy thats the way they are. i have never tried b-1s

30p QIV's will improve the slippage getting on plane, as you said, 28's are too small. The QIV-X 30 pitch is very similar to the B1's, they are bow-lifting props. Fountains carry their bows well already, and that is why the QIV's, a transom-lifter, improve top end speeds for fountains. It all depends on what you want your boat to do; best top end, or easier on plane.

I would be surprised if anyone here owns a fountain because it gets on plane well! A little blowout would be worth the extra mph's if they are there to be had.

Did the Q-IVs have diffuser rings? Supposedly adding the rings will help get on plane, and it's a crap shoot whether they sacrifice top end (minimally) or not.

That put's things into perspective... Thanks, Carder

The set I have on right now don't have rings. I don't have blowout issues getting on plane.
I may come back to you for those 25s but it'll be at least a month before I have an idea