22ZX high speed handling questions...

[Mudball]

A few months ago, I installed an HP500 in my little 22ZX.
I'm running a stock 28p Bravo prop now, hitting 77-78 on gps at 5,100 rpm.

The rear end, starting at around 75 does a 'wiggle', when I trim up. When it first started doing this, I assumed it was drive play, so I then installed a full hydraulic steering system (single ram, full hydro to helm). There is now zero slop anywhere in the steering.
It still does it.

It's hard to describe. The boat runs flat, no chine walk, but when trimming up, the rear end starts to go back and forth. Not a lot, but enough to be a little scary. If I trim back down, it stops, but of course, I lose speed. I have not been able to trim this thing out far enough to see the real top speed because of this.

Is this a trait of the 22ZX? Is there a different prop that would help this?

I do know that 3 blades don't work at all. I had major chine walking problems with a Mirage plus.

Thanks,
Kent

[Mudball]

I forgot to mention that this is the stepped version. 1999 model...

Any insight would be really welcomed.
Thanks!
Kent

[Uncle Fester]

I'm running a Hydro 4 blade and know exactly what your talking about. Damn thing porposes when I get her up to speed and I have to use the tabs to jam the bow down to keep her from hopping. Thing is - I lose speed since I'm plowing the bow and the ass end feels scary loose.


BTW, I did do the high speed 180 last summer. Lucky nobody got hurt and it didn't damage the boat. Got nice little fractures in the glass where my body slammed above the throttle. Now everytime I even slightly turn the wheel I'm totally aware of trim and speed (plus the butt puckers a little as well) thus the sticker:

[cneidhart]

Wow, You just saved me $$$. I have a 97 (non-step hull) and I'm hitting the same speeds and that boat is flat dangerous. Now I know the boat wasn't designed with the horsepower that you and I have but I can't get a handle on the stability at higher speed (70+).

I was under the belief that the 4 blade was raising the stern to much, making it bow steer. I was going to try (buy) a 28p Mirage and get more bow lift. All I've been using is 4 blade Bravos (26 & 28). You said you've tryed a 3 blade and it's worse?

She runs safer without the other bodies in the boat, less weight ahead of the engine. I can trim the engine to the MAXIMUM with one person in the boat and it seems stable. I can no way raise the engine enough to conpensate for the extra bow weight when I have other riders.
I've add the extended trim tabs, great for skiing, but not the answer at the high speed runs.

What's next? I like the boat but I need (want) a stable 70+ boat. I'm ready.
How far do you trim the outdrive? Does it improve? Did you do the same with the 3 blade?

[Dr. Dan]

:wavey: Guys....You're killing me here.........
1st.) I love that Sticker-Now that's Funny I don't Care Who Ya Are?
2nd.) Frank Civitano and Little Grizzly are the resident high speed 22ZX authorities here ...Bryan Tuvell had one but never reached those speeds.
Be patient or email Shanghied Again(Frank)...he will shoot you the straight story. :wavey:

In the mean time, do a search on the Performance Section on 22ZX's and read, I know there were posts about the Trim required to do turns to avoid the Spin Out...I know Frank ran regularly in the upper 70's to low 80's in his Super Charged 22...Lil Grizz scoots right along too...he just needs to learn where those Sand Bars are :D ... just kidding ya Mark.

Good Luck...

Doc :smash:

[Dr. Dan]

:banghead: :bonk: :rlol: :spit: :biggrin.:

[Shanghied Again]

What Blade are you running, Trim Tabs, also how far are you trimming the boat out? You should be using a Bravo 1 blade non labbed. with a 500 efi you should be a 30" pitch you also may have to run a bigger tab or try your tabs a neutral possition not up. this will give you more extension on the back. the big problem is you start running out of hull so you have to make up for it, I added extensions on to my tabs (Made them longer) Remember you have a step bottom boat so she getting a lot of air in the rear. 1/4 trim is were you should be at with the drive. My 98 ran 82mph supercharged.

[Mudball]

I'm running a Hydro 4 blade and know exactly what your talking about. Damn thing porposes when I get her up to speed and I have to use the tabs to jam the bow down to keep her from hopping. Thing is - I lose speed since I'm plowing the bow and the ass end feels scary loose.


BTW, I did do the high speed 180 last summer. Lucky nobody got hurt and it didn't damage the boat. Got nice little fractures in the glass where my body slammed above the throttle. Now everytime I even slightly turn the wheel I'm totally aware of trim and speed (plus the butt puckers a little as well) thus the sticker:

I don't have a porpoising problem. I also don't have tabs....

Man that is SCARY that you actually spun yours!! I have heard that tabs can make that tendency worse. I'm sure glad noone was hurt!

When I heard about these spinning, I got mine on the hairy edge on purpose at about 55, a few years ago. I did a hard turn and could feel the boat come out of the lean, go flat, and the rear end start to come around! It took about 1 millisecond for that to happen. I immediately straightened out and let off and it didn't spin.
===
It sounds like the rear end looseness you felt might be similar to what I'm feeling...I sure don't like it. Maybe 'loose' is a better term than 'wiggle'.

[Mudball]

What Blade are you running, Trim Tabs, also how far are you trimming the boat out? You should be using a Bravo 1 blade non labbed. with a 500 efi you should be a 30" pitch you also may have to run a bigger tab or try your tabs a neutral possition not up. this will give you more extension on the back. the big problem is you start running out of hull so you have to make up for it, I added extensions on to my tabs (Made them longer) Remember you have a step bottom boat so she getting a lot of air in the rear. 1/4 trim is were you should be at with the drive. My 98 ran 82mph supercharged.

Thanks for responding, Shanghied!

I don't have tabs.
Also, the HP500 is a carb version. A 30p is too much prop for my boat...I'm running a non-labbed 28 Bravo.

The 'wiggle' starts when I'm trimmed out about 1/3 to 1/2 on the gauge.

So, it sounds like I need some long tabs, and I'm trimming up too much!

Did you ever feel what I'm talking about before you worked on the tabs, or at any other time?
Thanks,
Kent

[Mudball]

Wow, You just saved me $$$. I have a 97 (non-step hull) and I'm hitting the same speeds and that boat is flat dangerous. Now I know the boat wasn't designed with the horsepower that you and I have but I can't get a handle on the stability at higher speed (70+).

I was under the belief that the 4 blade was raising the stern to much, making it bow steer. I was going to try (buy) a 28p Mirage and get more bow lift. All I've been using is 4 blade Bravos (26 & 28). You said you've tryed a 3 blade and it's worse?

She runs safer without the other bodies in the boat, less weight ahead of the engine. I can trim the engine to the MAXIMUM with one person in the boat and it seems stable. I can no way raise the engine enough to conpensate for the extra bow weight when I have other riders.
I've add the extended trim tabs, great for skiing, but not the answer at the high speed runs.

What's next? I like the boat but I need (want) a stable 70+ boat. I'm ready.
How far do you trim the outdrive? Does it improve? Did you do the same with the 3 blade?


While I don't know for a fact, I have heard that the non-stepped 22ZX's do like the 3 blade props...
I know my boat was flat out dangerous with a 3 blade!

[Shanghied Again]

Yes I have experenced the violent sway from side to side, the problem is any 22 ft boat is good till about 75mph after that you start running out of hull. the only way is to have K-Planes or extended tabs to keep the rear from swaying side to side. I even put bolster seats in my boat for comfort. I ran my boat hard and in big water

[Mudball]

Yes I have experenced the violent sway from side to side, the problem is any 22 ft boat is good till about 75mph after that you start running out of hull. the only way is to have K-Planes or extended tabs to keep the rear from swaying side to side. I even put bolster seats in my boat for comfort. I ran my boat hard and in big water

Thanks Frank. This is great info!!

A few more questions, if you don't mind...

What size tabs did you install on your boat? Did you mount them 1" up from the bottom of the V? Do you have a picture of the transom?
Thanks!
Kent