Vision221 overtrim for best Top speed

[ram750]

Hey guys,

I have a 221 Vision with 454 Mag 365hp and Bravo drive the boat is very solid and the motor seems 100% but I would like to know if I can help it achieve's top speed easier.

I have ran a best of 69.5mph GPS in very rough condition , the boat was virtually airborn the entire ride .. But usually it will run 62-63mph GPS in a decent chop. In order to run faster I can run past 62 ish by over-trimming the boat , I say over trim because I by-pass the trailer mode and go past the prescribed travel on the trim cylinders.. Now I am NOT talking about inch's here just a few super short blips on the button. The boat just loves it !! You can feel it ride on the back end and push forward right up to 67-68mph on perfectly smooth lake or chop! The boat shoots up a nice rooster tail when trimmed this hard.

Like mentionned higher up in my story , the trim cylinders are dialed in for travel as per Merc recommends , the engine is strong and the prop is a Quicksilver 25P 3 blade. Boat as got pretty large benneth tabs.I am very familiar with high performance mechanic and know the consequence of pushing the trim hard so I have been very careful with this procedure and am changing the joints for new one even if they are still fine.

What I am looking to know here is what could I do to help the boat ride like this without trimming this aggressively ! Maybe a different kind of prop ? add surface to the cavitation plate , nosecone Anything , any idea's ?

Thanks guys !

Marc

 

[wired]

Ive heard that adding a nose cone to a lower unit that doesnt need it to prevent blowout will cause a boat to slow down. I don't believe that for a minute BTW. It only slows a boat down if you tilt the lower up too high which seems to be your problem. You need a shorter drive and/or a different prop . Start with
the prop first. Its a lot cheaper to try out a 28 pitch prop than it is to swap in a short IMCO.

 

[ram750]

What kind of prop do you suggest ?

Right now it's a Quicksilver 25P Stainless and the engine spin's a solid 4900 near 5000rpm @ 68mph ... I was just asking about nosecone I figured it probably was not for me but love the look of a lenghten lower

I need to lift the stern further out correct ?

 

[keith4216]

Is it spinning 4900-5000 when over trimmed?

 

[ram750]

Yep , perty much ... I guess that more prop would bring that down a tad .. what is it 200rpm per pitch index .. ?

But the thing is will it spin the rpm's back up and the boat to speed ?

 

[keith4216]

I'm thinking your overproped and can't turn it until your over trimmed. Try a 23.

 

[ram750]

I did !

I bought a 23 Mirage Plus ... it would hit the 60 mph mark real easy but that be about it until I started trimming again and then would pass 5k right away .. Rpm wise I was limited to 63mph

 

[keith4216]

Just thinking if your going into trailer levels to get up to rpm the props to big but if your over reving a 23 to soon then I'm stumped for the moment.

 

[ram750]

So am I !

The rpm are decent on the 25 @ 63-64mph its spinning solid 4500-4600 , but there is a good an noticeable mph gain right passed that trim sweet spot then the rpm's go up some more all the way up to that 68 mph

 

[keith4216]

We are talking gps speed right?

 

[ram750]

Yep , sometimes my mph quote vs rpm is a lil off because the GPS does not refresh at the quickest of speeds but I am within 1 mph vs 200 rpm.

 

[keith4216]

I figured it out. Your in canada and going by American numbers.

 

[wired]

Thats right. You are actually going 63 KPH. I can swim faster than that. You guys and your heavy boats.

Seriously though. I'd try a different prop. "Quicksilver" is a brand . What is the prop model? Then I'd throw a couple of fat chicks overboard. I know their fun to ride when no ones looking but they still slow your boat down something fierce.

 

[SippyRat]

I know their fun to ride when no ones looking but they still slow your boat down something fierce.

Thanks for the laugh!

...Yes lighten the load

 

[ram750]

Cmon boys Haie ! I may have read the Gps in Kp/h but I am canadian , so no problem with fat chicks up here

The 25P Quicksilver is a very boring regular prop , .. I don't remember the part# on top of my head ... But it does not have any significant name or serie's written on it , no special blades or rake or cup... It actually looks alot like my Mirage Plus

Any way to get the boat to ride higher up ? My Senator 21 would ride up on the ass with a regular amount of trim and add the same prop but was 200lbs lighter.

 

[dream4ta]

i know that you have said that the limit is set correctly for the trim but it really sounds to me that is the issue. I am not an expert but i would make sure that you can run it to the top of the side pads on the drive before it stops. I have been in several bravo boats and most of them would throw a small roost at there best running trim setting. My only other thought is to try a better lifting prop like a bravo1. it will carry the boat better than a no name or mirage in my experience..

 

[ram750]

^ I like that answer very much ... I have checked the travel distance a few times to make sure they are correct .. I don't remember the exact number but it was measured Cylinder mounting bolt to cylinder mounting bolt if I am right.. something like 21 inch extended ..

Anyhow what is your method ? you said pads ? those things on the gimbal ring ?

About the bravo 1 I have been thinking about one of those , what pitch would you recommend ? same or 1 up ? or 1 down ?

 

[Gimme Fuel]

Cmon boys Haie ! I may have read the Gps in Kp/h but I am canadian , so no problem with fat chicks up here

The 25P Quicksilver is a very boring regular prop , .. I don't remember the part# on top of my head ... But it does not have any significant name or serie's written on it , no special blades or rake or cup... It actually looks alot like my Mirage Plus

Any way to get the boat to ride higher up ? My Senator 21 would ride up on the ass with a regular amount of trim and add the same prop but was 200lbs lighter.

Normally a Mirage prop has a lot of cupping and the Plus version even more so. Maybe yours was repaired at some point with the wrong blade forms and lost cupping. The Quiksilver versions were more tame and the balancing/quality control was not as good as Merc versions hence the lower price. If it doesn't say mirage on the side, then you may want to find a real mirage to try.


A bravo I is more of a stern lift than a bow lift prop. They can be labbed to make CM's fly well however but out of the box they fly very flat. A Revolution 4 has a ton of rake and cupping for lift but are harder to find used.

You may also want to check out Powertech props OFX3, OFS3 and OFX4, OFS4. They are a high lift prop and are supposed to give a better speed out of the box than the merc props. Prices are a bit cheaper than merc too. Im tempted to give one a try eventually once new motor is broke in.

 

[Brianh]

My 219 persuader ran best throwing about a 2ft rooster. It does sound like your trim limit is off if your gaining that many mph after going past the limit. My boat was a 94 219 persuader with a 330hp 454 running a 24 pitch 4 blade trophy plus. I had no problem running 70-71mph all day loaded. With a light load and perfect water conditions I would see 75mph. Just seems like your boat would have a lot more with the right prop and the trim limit adjusted.

 

[ram750]

How do you guy's verify the Bravo travel ?

Could have been doing it wrong .... since I am Canadian and all

Thanks for prop selection/suggestion you just listed Gimme Fuel that gives me something to look for !

I think the Mirage Plus SS is repaired since it seems a lil rough around the blade tips , it's also just a 23 ... Maybe a 25 Mirage plus SS would do ?

I agree the 25P quicksilver on there right now does look like a cheap'ish prop , the blades are thinner than the Mirage and less cup for sure.