Formula 311...
 

So I posted this in the formula section too.. but also am going to put it here to get more exposure. I have a 89 311 with 330s. It came with the stock 23 3 blade mirages. I never tried these props on the boat as I bought the boat as a project. I bought a set of 24 hydromotive as many people recommended them. Well after a summer of running I think I'm going to start messing with props. So it runs 60 mph at 4000 rpm, with 2 people 75-90 gallons of fuel and coolers. Won't pull past 4000 though. Also the boat starts to have a porpoise problem once you start trimming too. So my question is do you think I should switch to a 24 bravo since the prop is 1" smaller in diameter then a hydromotive, which in turn might let me turn more rpm, I mean I only need like 400 rpm more cause you don't turn these little 330hp much more then that. Or do you think I should step down to a 22 pitch hydromotive? Also I'm wondering if the hydromotive style cleaver prop is causing the porpoise?

Thanks!!

Hydro Q4's are totally wrong for that hull. The drives are set deep and you should run the Mirage 23's.

You want to spin 330's to 4600-4700rpms for the best performance.

So you don't think bravos would be good? I'm not a fan of three blades...always seem to blow out and slip really bad..

Best performance will most likely be with Mirage or Mirage Plus props.

You might see a few extra mph at cruise speeds with Bravo props, but on a 1989 hull, the drives are set way deep so they should not be needed.

I agree the Mirage Plus series is the props to go with.
In a 4 blade prop I would try a Revolution 4. We have both these props for testing.
I think your speedo might be off since the numbers you post suggest a 1% slip and that is impossible for your hull.

Brett