22zx and three blade props

[oldandtired]

Hey guys. I've seached the forums and have found alot of refences to three blade props on the 22zx being a bad idea but no real explanation why. I have a '98 22zx, stepped hull, 502 mag, Bravo 1. I ran a 26 Hydro all last summer and did a best of 72.8 (GPS) at 4800 rpm. I actually got it to about 4850 in January, when it was cool out, and figure that might have been an extra mph but no GPS that day. I'm just finishing up the installation on of a set of CMI tube tops and IMCO hydraulic steering which I hope pushes my speed above 76 with good stability.

I picked up a 27 Mirage too cheap to pass it up and wanted to try it out. It looks like it has been labbed but I'm not sure (the trailing edges are just over 1/8" thick).

My question to you guys is whether I should try that prop out with my setup (trying to pick up some more speed) or just leave well enough alone with the Hydro. The Hydro blows out when the hull is transitioning onto or off of plane. If I could cure that, I would be really happy. The boat used to have a 21 Bravo, but it obviously wasn't enough prop and had the same blowout when transitioning onto plane. I always like to tweak things and go faster, but I don't want to get anybody hurt. What do you guys think?

Thanks in advance,

Rene

[Shanghied Again]

I have been down that road, I had a Supercharged 22ZX running 540HP. Tried every prop under the sun. The 3 blades have way to much slip for the step bottom and it takes way to long to get on plane. Once on plane the boat was all over the place and squirrly as hell. The best blade I found was a 32Pitch Bravo 1 (Not labbed) she bought the boat to life and ran 82 MPH

[boldts]

Rene, has Frank mentioned, everyone I ever met with a slotted 22ZX found the Bravo1 prop to be the best prop on that Donzi. Since the Bravo1 is also a 4 blade, I'd start with a 25" pitch since you have a couple hundred RPMs to work with. I'm not positive of the diameter difference between the Bravo1 and the Hydro, but it should be pretty close since your turning 4800 to 4850 with a 26" Hydro. The 25" Bravo1 should put you right at 5000 or maybe a tad over. If it puts the engine too high in the RPM range, say 5100 or more, then you'll need to move up to a 26" Bravo1 prop and test again. Then its just a matter of using what puts the engine closest to it's RPM band. If you have kids and are pulling those blow up toys behind the boat, you may want to keep the lower pitched prop for use on those days and save the 26" for when your out by yourself and wanting to get from point A to B as fast as possible. Good luck in your test and remember, keep the drive trimed out in a turn rather than the usual trim in that is done with most V hulls. The step hulls are known to want to spin on their axsis in turns when trimed in while turning. Give Frank a call. He's an expert on driving the slotted 22ZX. :)

[synack]

So is it that the Mirage+ props are ideal for the non-step 22ZX and the Bravo1 is best for the stepped?

[22zxla]

my 98 22 steped hull came with a 23p mirage plus and im going bout 63mph at wot 4600rpms. Got a mpi 454 .wonder what the horse power on the mag 502 is that your going 72? would love to go 72! Althought got it to 95 once but it was on the trailer!

[billy22zx]

Had my 99 zx out for the second time since i purchased it. Finally got some smooth water to run on (ohio river) It has a 24 bravo 4 blade,and the best i could get was 62 (no gps) I did notice some cavatating at take off and had to make sure the tabs were down to get her to plane off nice. 4800 was my top rpm. I thought i`d try a 22 or 23 pitch prop and see what it does....any thoughts?

[BigGrizzly]

I think you will find the hydro is the better deal. My son tries both Bravo and a borrowed hydro that was a little small and it was better and faster. he didn't want to wait for me or the hydro so he took the 30 bravo1 prop. Did I forget to mention that he has a Wipple charged 454 on his I think 99 22ZX and runs in the low 80 mph with it. The prop works, but I feel there is mor to be gained with a better prop on this boat. The last time I rased him th ran 79 with 5 people on board. Of corse three were girls and didn.t weigh much because they had wicked weasels for bathing suits.

[oldandtired]

Thanks for the replies,

Got the boat out this weekend for the first time since February and got 4900 rpm out of it with 4 people and a full tank using the 26 Hydro. I am hoping to hit 5000 plus running light soon. I decided that I'm not going to bother trying out the Mirage.

Frank, do you get the prop blowout when you're transitioning onto plane? Mine blows out right as the bow comes down. If I hold the RPM's to around 3000 at that point, it will hook up and then I can do whatever I want with the throttle. If I stay in it, it blows out to the point that I have to start over.

Scott, thanks for the advice . I've got plenty of time on the boat now and experiment when I'm alone on trim angles and turning. When I have brought it around, it has been at relatively low speeds. I can't imagine how scary that boat would be coming around at high speeds. I am not much of a fan of pulling toys around, so my lower pitch props just sit around the garage. The kids have more fun driving anyways. I am still optimistic that it migh get to 5100 if I do some fine tuning on the fuel injection (adjustable FPR, poor man's style).

The hydraulic steering setup has really brought the boat under control. A mixed up chop would really upset the boat before. I had everything tightened down to the max and had completely gone through the transom and could not get rid of the steering slop. That is the best spent money yet on the boat.

Thanks again for all of the advice that I've gotten from you and everyone else on this board.

Rene

[oldandtired]

Hey Billy,

That 24 Bravo doesn't seem to be working that well for you. If your speed is actually 62, then your slip is around 15% (assuming a 1.5 drive). If your speedometer (I almost said speedo hahaha) is like mine, that speed is kind of optimistic and your slip is even worse. Get a GPS on board and go to bam marine's website. They have a good boat speed calculator and slip calculator. It helped me figure out that the 26 would be my best starting point and that has worked out well. My slip is running around 8% which is good for a stepped bottom and sorta high drive. Yours should not be that much worse. You need to address the slip issue somehow. A different style prop may be in order. A lower pitch prop probably won't take care of it.

By the way, when I first got my boat, it had a rotten 454 which I replaced with the 502 mag. I left the prop alone on my first time out. That prop was a Bravo 21. I hit the rev limiter instantly (5150) at about 62 on the speedo (no gps). I changed that prop to a borrowed 21 Hydro and the speedo went to about 67 on the rev limiter. That alone told me that the boat liked the hydro better than the bravo (same pitch, same rpm, better speed).

Good luck,

Rene

[oldandtired]

Well, I was bored in the garage and saw that Mirage prop just sitting there waiting to be used one day and decided to waste some time with it on the boat. Grabbed a GPS and took her out for a spin, 75.7 MPH at around 5000 rpm. A little slow out of the hole, but doesn't blow out that bad. Boat seemed more stable than with the hydromotives and could turn better. I still need to get my hands on a Bravo 1 prop, but I don't feel like spending any more money on the boat for a while. I didn't even want to try the Mirage because of other peoples experiences and thinking it would be a total waste of time. Now it makes me wonder if my boat is just crazy out of control with the hydros and the mirage just feels more stable??!!

Rene