What type of prop is better? 3 blade? or 4 blade?

If your drive height is stock, the best prop for a '97 24OL is a Mirage+ three blede. It gives the highest top end and good mid range as well. It all comes down to what you want it to do. A Revolution4 will be better in time to plane and mid range efficiency with lower top end, but on those older Baja's the drive sits deep and a three blade usually works the best. The B1 is not the best choice for that boat. You'll need a prop with bowlift for that hull, and the B1 has not much of that + the diameter is bigger than you need, it's a waste of speed and power to use it on a 24. Only if your drive sits high and maybe run a shortie with big power, a B1 would be the prop to consider. IMO, if you want to run a 4 blade, stay with the Rev4 untill you run out of pitch. It has more bow lift than a B1 and the 14.625" dia. is plenty for the single engine Bajas.

I just bought the boat. It has a custom 4 blade spinelle prop, specificly made for the boat. Don't know the pitch, It was custome for that boat.

The boat has a 502 merc ho, with a m1 procharger. The Boat top speed is 80mph

At what rpm's are you spinning @ 80 mph? I assume your drive has a 1.5 gear ratio. Is there any numbers stamped on the prop? It is really hard to determine anything without a pitch number.

If you can't find the pitch anywhare, a good prop for baseline testing would be a Mirage+ 27". With a 10% slip, a 1.5 ratio and 5200 rpm's will put you @ 80 mph. Then take it from there. The B1 on a high hp 24' hull might create prop torque issues, but you could try that in a 28 as well.

I don't remeber. I only had the boat up to 78 mph one time, didn't push it anymore, was holding on for dear life, with my mechanic. I will have to experiment with it in the spring.

Gear ratio i don't know?
My mechanic looked and didn't see anything on the out side of the prop, , he said to look further he would have to take it off, I told him not to bother at the time

I have the factory mirage 3 blade prop also.

The boat has alot of torque, because of the engine power the original owner said.


What do you mean by prop torque issues? Please explain in more detail.

Thank you for all of your information

jj

Hey no problem.

Prop torque is a condition where the rotation of the prop affects the handling of the boat. It can be an issue when accelerating and cornering, The prop "twist" the boat opposite to the rotation direction and can make the boat lean outwads in a right hand turn. It can also make the boat lean to port and list or crab, when going straight and accelerate, if it's a RH spinning prop. On single engine boats with a LH rotating prop, the condition is often amplified because of the engines LH rotarion. It is not the most common thing, but on smaller single engine boats with big power, it sometimes happens.

The drive ratio is stamped on the upper port side of the drive. See pic below.

What is the pitch of the original Mirage prop, and what max rpm's are you spinning with the 4 blade? I assume the speed is gps.

The other thing I would highly recommend if it isn't already on there is hydraulic steering running those speeds on a cable your asking for serious trouble.

Friend of mine running a 25OL with 454 stroked 496ci and 3.3 Whipple is running a custom 28p Bravo done by Bblades. He's running around 84mph with this setup. I also know of a 272 with a 509ci Procharged running around 80+ as well. I believe he's still running a 4blade Bravo think it's a 28p too.

I am not sure , i will have to look at it. The rpms on the 4 blade I thought were 5800, I could be very wrong. The original owner had it gps at 85mph once. But he told me the boat ran all the time at 80 mph on the gps. I just have a normal speedometer on it. We had it up to 78 mph, and more room to go on the trim tabs, and we didn't even touch the out drive trim on the boat yet.

i will have to yank the old prop out of winter storage and look.

Thank you for the pictures

jj

Thank you for the helpfull suggestion. The boat came with a side winder arm "latehm company called it" I guess it is a shock absorber arm, nonfunctional. Only a arm with no hydraulic unit. It is like the arm on a hatch for a suv. The salesmen at lathem, told me the arm is conter productive. It makes everything stiffer, but cause everything else to work harder. I plan on gettinga hydraclic add on arm to the steering unit. then in a few years get a whole system from steering wheel to out drive.

I found this out a few months ago by being on this site. At high speeds 75 and up it seems like the back end moves aliitle bit. Like on a ice road in a car. Dave from xt innovations, said it may be happening becasue at high speeds, i need more support in my outdrive, and i have a little play in the steering and it shows up at higher speeds. I hope this summer I put one on or definitly next summer. I usually, don't do high speeds every day, i have my 5 year old on the boat , so once in a while with out him, i open it up alittle

I appreciate your concern

jj

my 24 runs mid 80s with 650hp, I have 2 steering set ups one used for sale and one new. plus a full set up. I am going to part out the boat. so the new stuff in in the boxes. we just finished my saber and we are dialing it in. pm me or call me 617 833 3327, if I can help. I had 5 different motors over 14years, and ran a shortie drive until it was stolen. art