cdail28590

iTrader: (2)

The boat is 24/7 Python that has about a 4" pad on the bottom. Motor makes around 500hp, timing is at 35 degrees, and the cam is Bob M. custom made to pull to 5200 rpm. After running 3 props on Sat. we found out that the drive is a 1.36 drive and not a 1.5. This was something I had suspected since the boat originally had a blower motor and I have a article that showed a 24 Python that left the factory with a blower motor and 1.36 drive. The cavitation plate on the drive is 3" (I didn't measure exactly but this is by looks) above the bottom of the boat, so it appears to have a high X.
Prop #1 27p 3 blade Mirage rpms 4200 mph 64.5
Prop #2 26p 4 blade Bravo 1 rpms 4400 mph 67.1
Prop #3 26p 3 blade Labbed Mirage rpm's 4400 mph 67.6
Prop #4 25p 4 blade Revolution rpms' 4600 mph 69.8
Prop #5 25p 3 blade quicksilver rpm's 4800 mph 68.3
Prop #6 24p 4 blade Hydromotive rpms 4700 mph 70.1
Prop #7 23p 3 blade Mirage plus rpms 4900 mph 71.6
The boat handled the best with the 23 Mirage plus as it didn't seem chine walk as bad. With the 23 Mirage its running a 9% slip. With this hull and motor I should easily be at 75 mph. Should I keep going down in pitch trying to get the rpm's up or just run the 23 Mirage plus? Anybody have any suggestions?

Flying Tomato

I have the same boat (95 Python). I haven't owned the boat very long so I have not had a lot of seat time. I just recently found 3-4 mph just in the way I drive it.

Do this: Get up to speed (around 40), trim up until the prop actually starts slipping (rpms should increase 100-200 with boat speed staying about the same) Now ease into it and open it up. On my boat this increased top speed 3-4 mph, AND increased my rpms 300-400. The first time I did it was by accident because it doesn't feel right.

I have owned 7 boats and have never had one respond to trim like this.

Let us know your results,
Lee

Flying Tomato

By the way, I'm looking for a 27p Mirage (non-plus). What's the story on the test prop you were using. I need a good deal!!

baja208

I run a similar hull. I bet a 24P bravo would run well. They are respectable numbers your running. Was the 4 blade hydro a QIV or QIVX.

I ran a 25P Rev 4 this weekend and my boat didn't like the increased blade area on the Rev 4. My hull likes the bravo 1 or QIVX hydromotive.

Flying Tomato

Here are my numbers:
Mirage + 25P (with .5 inches taken off diameter)
5500=80mph trimmed out till it slips 5850=83.5 gps

Turbo 26p
5200=79.5 trimmed out till it slips 5500=83

As you will notice my slip % goes up when fully trimmed out, but overall speed also goes up.

Motor is a 540 that makes approx 625hp (never dynoed)
I really want to try a mirage 27P.

articfriends

iTrader: (1)

Well you still didn't hit your target rpm even with only a 23 mirage plus so I would either re-gear the drive to 1.50's or get a labbed 23, anything taller is obviously too big and it sounds like your boat likes 3 blades as far as handling, Smitty

articfriends

iTrader: (1)

If he could only turn a 23 mirage plus 3 blade 4700 and needs to be at 5200 then I can't see a 24 doing him any good as it will drop rpm's further, Smitty

Griff

Have the 23 Mirage Plus labbed by BBlades and call it good.

gellis11

I have a 4 blade 22p you can try. Call me 980-622-5371.

Dave M

How do you know? Dyno? Sounds like you might not have as much HP as you think.

I owned a 24 Superboat and the Bravo 1 prop worked well for me. With a Mirage+, I chine walked all over the place and top end was the same as with the bravo. I was running 78 (GPS) with only 425HP. My slip numbers were 10-12% depending on RPM.