blownboat

25 daytona single step. 7lbs procharged 502 mag

30 lab bravo =plained out good . Hit rev limiter 5400rpm 85 mph on gps
34 natural bravo= prop wanted blow out while planing. 5000rpm 91mph on gps
31 hydrmotive p5x = prop never blew out,plained out at 2100 rpms,boat turns better and seems like it runs smoother.5200 rpms 92mph on gps. I dont think the 34 bravo would plain out with full fuel and 5 people, it was on the verge of blowing out until about 45 mph. The p5x ran a little faster and it never wanted to blow out ever. Made the boat feel totally different. Seems like a great prop, thanks Julie at throttle up. I told her my numbers and she got me the right prop the first try!

blownboat

We also tested another 25 daytona with a double step and a really high x dimension. He could not plain out with the 34. He was using a 32 lab bravo and clicked 112 on the gps. It also wanted to blow out a little. With the p5x he plained out easily and he went 115 mph on gps and he never blew the prop out.

Turbojack

What were your rpm's with the P5x? What were the rpms with your friends rpms

blownboat

My rpms were 5200. His were 6300 on his recall tach. He thinks he could have went maybe a little faster but the rear of his boat was getting a little squirelly he said. I am not running a nose cone and he is. I wonder what that would do for my numbers. He of course is running a much bigger motor.

shawn

How did they carry the nose? I thought the P5X is a bow lifting prop. I run the regular P5s and the Spectre runs flat, but when I run the Bravo 4 blades, the nose is about a foot higher than when the Hydromotives are on the boat. I like the Hydromotives much better.

jspeeddemon

That is the problem, I was told, with trying to run a 5 blade on an eliminator tunnel. It picks up the transom too much and makes the boat feel loose.

gmnhra

good info on setups...
i have a 25 single step and have monkeyed around with many props...according to eliminator (jerry may), the single step should be setup to run "flat" and the two-step with 5 degrees of bow lift...

i tried a 5 blade 30p hering....blew out trying to plane..had major issues trying to get hering to "fix" it....it looks real nice hanging in the garage...

various 4 blade b1....and settled on a 32p non-labbed...right at 112 at 5600

my setup issue was to get rid of the 60-80 mph "hop"...i was told to have the "rake" taken out of the 4 blade to give a little more transom lift to make the boat run flat...

very interested in the details on the setup with the 5 blade hydro...where is the "x", how much trim, any mid range "hop"....

thanks
gm

blownboat

How did you get your slip so low to get those speed numbers? As for the prop it is a bow lifting and my boat (single step) runs flat. Seans(double step) runs with the nose up. You can see light through the tunnel when he is coming towards you. I think maybe his x is too high,he said it is squirrely with any prop but it felt a little better with the 5 blade. We will measure the x's and post soon. Both boats at 90 mph the single step feels more stable.

gmnhra

10% slip is about right for a cat....
on the calculator...
5600 (hit limiters) @ 10% with 1.36 gears and a 32 pitch prop gets you at 115mph....so 112 was right in there...

i have found a big difference in props at "cruising" speeds.. i use 3000 rpm as my reference....i see 60mph with the 32p 4 blade...with the 5 blade hering it was slower (55 mph)...that did not make much sense to me...

are either of the 25's discussed above using a standoff box???

gm

blownboat

No,I figured you must be runnin 1.36 gears. Did you notice a big diff with a nose cone?