Tested a few props now what?
 

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?

same boat
 

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

test prop
 

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!!

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.

same boat
 

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.

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

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

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

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

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.

The motor was dyno'd at 451 hp with stock oval ports and I have since put on World 320 cc heads and a Edelbrock rpm intake so I figure they gave me another 50 hp. Plus talking with Bob M. he didn't believe the dyno #'s after we discussed some items so he thought the motor was 500hp with the oval ports. Your Superboat is lighter than my Python and I don't know if my drive X was raised from the factory or if its normal but from looking at other boats it seems higher. The 1.36 gears are another difference that some people aren't taking into account. I don't know which hydro prop I ran as it was a buddies and he just let me use it. As far as the chine walk, all the props had some chine walk in them. The Mirage plus just made the boat feel flatter and the chine walk wasn't as noticeable (scary) as others. I have tested trims settings and I am trimmed similiar to what you suggested Tomato. I am actually throwing a pretty nice roaster tail getting these #'s. Glenn I'll call you about trying your prop. As far as the 27 I used, luckily a extremely nice gentlemen (Monza 24) from this site shipped this to me along with a labbed 26 to try without ever meeting me. Super nice guy and I might just take them back to him personally to meet him.

I don't know about the Python, but I think the 24 pantera is about 500 lbs heavier than the Superboat. With that said, I could still usually hit 75 with 4 adults and full gas.

I know every hull is different, but I wouldn't expect a huge performance diff. between any of the 24x7's.

As far as the rooster tail, if you have one with a standard bravo drive, I think you are loosing thrust. The boats I own(ed) a rooster meant I was over-trimmed.

Good Luck! :drink:

How about bow lift?
 

Are you getting enough bow lift?? It wasn't until I trimmed WAY up that I felt the bow lift and the boat get really "lite".
FYI--my propeller shaft sits 6.5 inches below the hull when parallel.

I think my X is higher than yours Tomato. I'll have to actually measure it but I think my prop shaft is about 3.5" below the bottom of the boat. I talked with Bob M. about the motor, heads, and cam combo and he is sure the motor is over 500hp and that it should easily pull to 5600. He suggested I might have a problem somewhere else and to just start with the basics. He suggested I try a larger carb and we discussed fuel line sizes. I am running a 850 Sea Demon carb so I have enough carb so then I started looking at the fuel system. I put 3/8" line in but the fittings might reduce the size down and the carb feed line going to the front and rear of the carb appear to 6an stuff. I just ordered all new 8an fuel lines and fittings last night to completely replace all the lines and fittings from tank to the carb. I hope to have it all on by the weekend and maybe get another run to see if the rpm's improve. If not we will go back and check to make sure the pushrods are opening the valves all the way.

Try the 22p. I heard it is the most effiecent pitch. People go to 1.36 just to get down there

I was expecting to re do my fuel system this past weekend but UPS delivered the package to the wrong house and I didn't get it until Sunday afternoon, so I will be working on the fuel system during the week. Flying Tomato, I measured the prop shaft distance to the bottom of the boat and it is 5" from the centerline of the prop shaft to the bottom of the boat. I should be trying the 22p prop this coming up weekend. Hopefully.

I agree, need to get RPM up 5200-5500....

Great thread. Can't wait to see what the results are.

if you use a23 mirage prop not a plus ,it will give you 200more rpm i have a 24 baja 136drive 718 hp dyno i run a 23mirage going over 80mph at 56oo. my motor is built to 5800. the closer you prop to your red line the better your speed will be . two years i been working on this ,finnaly got it dail i:drink: here me racing a 70mph waverunner http://www.youtube.com/watch?v=jmnD9..._order&list=UL good luck once you get the rigth prop you will be happy! one other thing i try a 23pitch with 150 gears and 136 at 3000did 40mph the 150did3600at 40 thats test was on my boat .so i get great midrange

I got the fuel system all changed and got the 22p prop from gellis this weekend but it was 2 cold to mess with it on Sunday and I was to hungover to want to mess with it. This upcoming weekend should be nicer so I should be able to get it out and run it. I'll keep everyone updated.

If Bob M told you that motor will pull to 5600 RPM,you need to prop it to turn 5400 to 5600 rpm.
If you are only turning it 4700 rpm ,its a good chance you may be detonating and losing power.
It would be faster with 1:50 gears and a 25 or 26" pitch prop instead of the 21 or 22 pitch with 1:35 gears.

Got a chance to run the boat this weekend with the 22p. The 22p is a 4blade power tech prop. The boat only ran 68.4 at 4900 rpm. I put the 23 mirage plus back on and it ran 72.5 at 4950 and might would have run quicker but I ran out room where I was testing at. It looks like I am looking to get a 23 Mirage plus and then get it labbed, as the one I am using I borrowed from a buddy. Both props show a 9% slip which I think is pretty good for out of the box props. I didn't see where changing the entire fuel system helped (more wasted money) but at least I can add more power without having to worry about fuel issues. I did play with the fuel pressure and with the fuel pressure at 7.5 and the 23 Mirage it would run 69.5 when I put it back at 7 lbs it ran 72.5 all this on 64 degree cool day.

23" Mirage +
 

I have a LH 23" Mirage plus if interested. Real nice shape. It does use Hub kit, not solid hub.

Thanks Fastech for the offer but my boat does not like LH props. I tried one and it listed terrible while underway. If it was a RH I would be all over it.
Thanks