Better Hole SHot

[Ramman]

Hey everyone, I've got a 1987 Z21 with the 454 330Hp and the alpha drive, Im running a 14 3/4 mirage stainless on it. Im looking for suggestions on how to get a better hole shot, I I've gone threw a few different props and the Mirage seems to be the best one for this boat. So Im either considering motor modifications? or? Any Suggestions?

[Lenny]

What pitch are you running, what are your revs, what is the drive ratio?

[Ramman]

Sorry forgot to put the pitch, Im running a 21 pitch, not sure in the Ratio...Im running between 4200 and 4500 RPM's Top end I believe the boat is getting around 60 MPH.

[Woodsy]

Ramman....


Alphas don't live long when used for holeshots... especially with big block power. You are on a very expensive path....

Woodsy Von Outboard

[blackhawk]

I have to 100% agree with Woodsy on this one. 330 hp and an Alpha is pushing it. And pulling holeshots you are just waiting for something to break. I would pitch it down to a 19 to make the motor and drive labor less getting on plane. Just my $.02

[boldts]

Ramman,

Are you wanting holeshot for getting skiers up out of the water? By your rpms, a 19" pitch should put you right in the ballpark for the 454 engine wot rpms. (4750-4900) Turning 4200 wot is why your holeshot is also suffering.

Now, if you want better holeshot because your sking behind the boat, you might even drop the pitch 1 or 2 more inches. Only precaution is be aware that your speed will probably decrease and if someone accidently floors the engine, you could put the rpms up in the 5500 range which could damage engine parts.

Most of the time, a boat propped correctly in the first place (In your case to run about 4800 to 4950 at wot) will also have a decent holeshot for sking purposes. You might try a 4 or even a 5 blade prop with small pitch, but that's up to you. I'd give a reputable prop shop or company a call. Tell them your goals and current performance. They'll be able to lead you in the right direction. Good luck!

[blackhawk]

boldts, I thought the older 454's (310 and 330 hp) had an operating range of 4200-4600 rpm?

[Ramman]

My RPM's should be between 4200-4600, so Im right where I need to be with the 21, I had a 19 on it and the boat was way over red line, I believe it was around 5000 RPM's. We do ski with it, but not enough to buy new props just for that. I know the alpha and the 454 don't do well together. The drive is only 2 years old, the previous owner killed the original one. I've already inquired about doing a bravo upgrade. But as you can imagine it's very expensive, and I can't justify putting over 2000 grand in a boat thats only worth 10000 maybe. I was more or less looking for simple bolt on mods, (intake, carb, exhaust).

[blackhawk]

What about finding some used trim tabs and installing them? Or if the boat already has them putting some longer tabs on. That would be easier on the drive and help you get on plane easier while keeping the 21 pitch.

[boldts]

Ramman,

Disregard my post. Sorry, didn't know there was a difference in the wot rpms. Figured 1 454 could turn the same as another 454. Thanks BlackHawk.

[blackhawk]

Something I just thought of. Did you make sure the drive is going all the way down? If your limit switch isn't letting your drive go down you will have poor holeshot. And trust me, it doesn't take much!

[Ramman]

Thats not a bad idea, I will check that next time I get it home. Blackhawk what part of michigan are you from? Im also a snowmobiler.

[blackhawk]

I'm in Cadillac about 90 miles north of Grand Rapids and 50 miles south of Traverse City. I do most of my boating on Torch lake. I was a snowmobiler for years but just sold my last one. I've owned 10 Polaris sleds in the last 12 years. The one I just sold was a 200hp, 450lb "XC600". Ran about 95 mph in 500' at about 5.2 seconds!

I had an Alpha drive that wasn't going down quite all the way. Close, but not quite. Boat took forever to plane. Like I said, it doesn't take much.

[Formula Jr]

I hate saying this, but the Z21 is a very unresponsive boat unless it has big power. I had a little time driving one with a 350 mag and Alpha and couldn't find a sweet spot. Even in PERFECT water to find the right trim setting, it had me baffled. It either ran flat, almost plowing and diving or flipped up too much. I could not find a middle ground with this boat. I've experienced the same thing in a Cig of same lenght and a 350 mag with an Alpha. The zero effort controls do not help. There is little feed back. I think the CG was off and there is too much weight forward for a 21 footer. It would be neat to run one with a 502 or 496 and a Bravo in it for comparison. This boat needs a big, heavy engine. In light water, I could see that the boat can be aired out and run fast. I pulled over on a bluff at Chelan to watch Eric tweak every inch out of his old boat. It just takes a long time to get there.