25p vs 23p, same wot rpm?
 

Hello,

I've ran the boat twice so far and coming into some issues. Last year I bought the boat with a mirage 25p prop and could spin it to about 4500 rpm. Since this is a 454 mag, I had a few more rpm to go so I bought a 23p mirage plus to try and get it to around 5000 rpm and more speed.

So far, the two times I've really dropped the hammer I'm still seeing 4500 trimmed up and slower speeds than with the 25p.

It's a 89 Python vector, temps are good, oil is good, plugs are good, but can't seem to get it higher than 4500 and even then, I was only seeing about 53 on the gps - which is slow for my liking. Throttle cable seems tight but maybe the carb isn't opening up a the way?

I see about 25 mph @ 2200 rpm. 32mph at 3000 rpm at a cruise speed with the 23p plus.

Any ideas? Switch back to the 25?

Are both props Mirage +? or is the 25 a Mirage? There is a difference.

Like Dave said, Mirage + and Mirage (non-plus) are different props. Mirage Plus has more cupping and is harder to spin than the same pitch non-plus. Thus, I'm not surprised to hear they turn the same RPM.

Run the faster prop.

The 25P has a part number 48 13706 A41 25P. It doesn't say Mirage Plus on the side but if I search the part number, some list it as a plus - so its a bit confusing.

Either one I run, using the web calculator, I'm seeing around 20-21% slip which is high correct?

Yes, 20% is high. BTW, I had a 24 Superboat that is similar to your boat. It ran the best with a Bravo 1 4 blade.

Ive been looking online to try and reduce slip %, but I don't want to go crazy trying to chase something I may not be able to fix. The 23P Plus got up and running way better than my other prop, I just want more speed!

If I see an honest 60+ mph Id be happy.

Weird, I have almost the same boat but with a tad more HP than you. My boat will spin a 23 Mirage Plus and a standard 25 Mirage at the same RPM (4800-5000) but it is faster with the 23 Plus. Was the load on the boat the same when testing props? people, fuel, gear, etc?? I still want to try a 25 Plus, I got some rpm to play with.

Similiar boat... same basic hull... with a 330 454 I spin a 23 standard mirage to a best of 62.. your maybe a couple hundred pounds heavier if anything (the extra 18" should not make much difference} going to a 24 cost me 2 mph.

The 24 Superboat I had with 385 HP spun a 26P bravo 1, or 25P Mirage + @5000 rpms, 73-75 MPH. With the Mirage + I had a scary chine walk and couldn't keep it hooked up in rough water. I ditched it and stayed with the bravo 1.

I later repowered to a 496HO (425 HP) and could spin a 28P bravo @5000 rpms, 76-78 MPH.

You have a 454 Mag, 350 HP? You speed sounds way low. I would think you could run at least 65.

Are the props in good condition? Have you ever weighed your boat?

You dont have the early 454 mag/alpha do you?? that was a 330 not a true 385 mag