I have a set of 29 hydro's quad 4's on my 2001 Fountain Classic. The first time out I spun them around 5800 which is peak hp from the dyno. I want to test them again to be sure when I get the boat back after installing relief valves.

My question is would I experience any speed gains by moving to a 30 quad 4? I also, have a pair of 28 labbed Bravos to try, but thinking they maybe too small? Thank you.

Dyno sheets need to be read carefully. You don't necessarily prop at the ultimate top hp. You are better off a little below that in many situations.

In your case, going up in pitch with a little prop tweaking will most likely give you some more top end.

Also to answer your question, Anytime you are on the limiter or above max recommended rpm, going up in pitch is a logical move.

There are times under propping can be useful though.

In my particular case, the peak hp is at 5800. Rev limiter is set at 6200. About 11 hp difference between 5600 and 5800. HP at 6000 drops 16 hp.

if you're turning the 29 Q-IVs up to 5800, you'll be spinning the 28 Bravo I's quite a bit faster. My understanding is that Bravos turn like a smaller prop than advertised and the hydro's turn like a larger prop...

The Hydros have a larger diameter than the Bravo I props and the Bravo I is approx. 1 inch less than is stamped on the propeller.

Julie