Hey Scott B

[RedDog]

Your post from another thread said "Finally had the opportunity to run my 22 at WOT. She's only turning 4200 at a speedo reading of 72 MPH. Sorry, I forgot the GPS at home. "

Your 22 is the only one I've been it and I was impressed with its acceleration. I eyed the speedo at a touch past 70 that came in a hurry. And that was through a lot of sloppy water. What do you think we were really doing? My inexperinced seat of the pants said that had to be real close.

PS - the ride did convince me that when I grow up I'm going to get a 22 Classic :D

[boldts]

Hi Tim. Spent most of my day doing some research on my 22. Schumaker Performance Inc. in IN did the updates to the engine and the Bravo1 drive when the boat was brand new. The first owner had a Procharger with 7lbs. of boost and a 502 EFI added to the boat. They also beefed up the internals of the engine. The outdrive was changed from a 1.50:1 gear to a 1.36:1 gear and again the internals were beefed up. As best I can tell, I still have the drive from the set-up because it still has the drive shower that was added. (If anyone can tell me how to turn the engine and check the rotation of the prop, I'm all ears!)

The owner then traded the boat in on a 32' Fountain at Lake Cumberland Marine. The marina pulled the 502 engine out of the boat because they were afraid of selling the boat to someone and them killing themselves. Thus, the lawsuit that would occur for selling an unsafe boat. I was told the boat was very wild once it got up over 80MPH. Boat was said to run almost 90. Who knows, maybe more set-up time was needed.

When pluging the numbers into a speed calculator, they just don't seem to jive. Two thoughts here come to mind. Either the tach reading is way off or the speedo reading is way off or both. I'm planning to go to the lake tomorrow after work when hopefully the lake will be quiet due to firework shows. GPS will be in hand for sure so I can get a true MPH reading. We noticed another tendency of the boat this past weekend and that is from 40MPH up to about 55MPH, the boat really porposes a lot. It will be interesting to see if that continues without the backseat weight. The boat came with a 23" Mirage prop. I haven't been able to get any answers on whether the prop could be the reason for the porposing. I don't know if it is lack of knowledge or what, but I also couldn't get an answer about the difference in diameter between a Mirage and a Mirage Plus propeller.

Prop suggestions were varied. The Turbo is a 141/4" dia. so it was felt that I could run a 23" Turbo. That is if the tach is correct. A 21" Mirage Plus was also suggested and even a 22" Bravo1 4 blade to help the porposing. Once I get true readings, I'll be able to start prop tuning.

To get back to the original question? Best guess is the boat is running around the 65 to 68MPH range. GPS will tell tomorrow! :)

[boldts]

Just got home from the pond. Speed = 65.2 on GPS with a full tank and 2 1/2 people on board. Tach is not stuck on 4200 either as she was turning 4800 tonight. Drive does go all the way down as I checked that before going to the lake. I can't explain the porposing, but it appears the prop is very close to what should be on the boat.

[McGary911]

I'm pretty sure you can check the drive ratio by marking the harmonic balancer (or just using a timing mark) and putting a piece of tape on the prop. Use a breaker bar to turn the engine 1 revolution. the prop will either go around 1 1/2 times or about 1 1/3 times. That should clear it up for you. I've never done this, but that sounds like it should work, right?

[Tomahawk]

Scott - the numbers sound almost identical to my boat with the Mirage Plus 23. Drive ratio 1.5 to 1. Except that I was able to twist that prop to 5000 and about 68 mph.
Regarding porposing, it seems the slower you go, the more down trim you need. The more up trim you use, the more throttle you need to keep the boat from porposing. Try a high speed run and then slow down without changing trim. The boat will start to hop for sure.