Captiva 192 Worked 4.3L hitting Rev Limiter at WOT. Which Prop to fix.

sethman919

I just bought a 99 Rinker 192.  The engine was professionally rebuilt last year.  Bored 0.02 over, Edelbrock intake, edelbrock 4bbl and Comp Cams.  The shop that rebuilt it estimated 240+hp.  The boat currently has a 14.5" 19p on it.  It gets on plane quickly but hits the rev limiter at WOT..  I would like to get a little more top end out of it and be able to run WOT without hitting the rev limiter.  I will be ditching the whale tale and installing Smart Tabs this weekend to help with plane time.  I suspect a 14.5 21p will be the right prop I would just like some more input before I lay down the cash for a new prop.

Thanks

Black_Diamond

1" of pitch moves your rpm 200. So add 1" of pitch and you will drop 200 rpms. 

mvn

Black_Diamond said:

1" of pitch moves your rpm 200. So add 1" of pitch and you will drop 200 rpms. 

Agreed.   But who knows how much is necessary to get below the rev limiter?

What is the WOT max rpm? As the throttle is advanced, when is the max WOT rpm reached and how much throttle is left?

Good call on the hydrofoil...... 

Mark

212rowboat

I'd personally go to a three blade with an aggressive rake and transition.  Meaning the leading edge is likely 19p and the trailing edge as much as 23p, with smooth transition and average of 21.5 to 22p.... I'd make sure it has a good cup to it, and the rake for bow rise.. The trim and smart tabs will help you counter that in an advantagious way... The most important part, though, if going with a 22p average, is to make sure it's vented, and has different size plugs you can interchange... I'm a big fan of vented props, as it turns out...  a precision turbo ii comes to mind, followed by a laser ii and then the mirage ii... In that order, and in my opinion each fine props. 

Michael T

I have had a precision prop and it was amazing.

mvn

Agreed,  Precision Props are solid performers. 

Mark 

sethman919

Thanks for the input guys.  I'm getting it out this weekend for the first time other than the test drive.  Will have the smart tabs on and Hydrofoil removed for the test.  Ill see where my RPMs are and how much throttle i have left.  Still searching for a friend who has a 21p for me to try,  thinking that empirical testing is the only way to go to know for sure.  Just dont want to buy prop after prop to find the right one.

212rowboat

fwiw, check out eBay and want ad's.... I paid a whopping $40 for my precision turbo 22p, and $12 shipping... that is a stainless prop that was in perfect shape... some folks just don't know what they have... I sold it for $75 to a guy who needed it, as it was a spare after buying the Ron Hill Pleasure Five 19p (which I freakin' love), and he had torn his up on the way to the sandbar... $75+ five minutes worth of work swapping it out, and he was a happy rascal. 

if you can find a merc dealer, they may still have some blue props, which were meant for potential customers to test them out before dropping coin to buy it. 

sethman919

I just went ahead and ordered a 21p... I'm pretty sure it will be good as it was the original spec prop for the boat.   

mvn

Have a look at this.  These are the calculations on a stock 4.3L Volvo.  As you can see, a 20" prop is just outside the max WOT spec.  This was OK as the boat was used for watersports towing and no WOT runs.

Mark

sethman919

Those calcs were also made with a 4 blade.   not sure the effect the 4 blade has on the numbers.

mvn

sethman919 said:

Those calcs were also made with a 4 blade.   not sure the effect the 4 blade has on the numbers.

Exactly..... Just a data point for discussion purposes. 

Mark

sethman919

Resurrecting this thread.  I've been running with the 21p Aluminum 3 blade for a while and it was good, but as I've gotten more into tow sports i find it a little slow on plane.   I have smart tabs on the boat now.   I bought a 19P 4 blade SS Solas HR titan.  This weekend i tried it out for the first time.  The boat now JUMPs on plane with just me in the boat, but with weight in it or pulling a tube  the torque is causing a HARD list to the left.   I'm on the fence with just going back to a 19P 3 blade in stainless this time or getting a 21p 4 blade stainless.  I can't keep dropping money on props to try them once and have to resell.  Any help will be appreciated.

Thanks,

NRath

I'm running a 192 w/V-P 4.3, fuel-injected, rated at 220 hp.  Stock prop was AL 3P, 21", 14-1/4 (or 1/2?).  When I bought it, it seemed very slow to plane.  Not functional for us with watersports and cruising.  I added Smart tabs and went to a  Solas 4P, 19" Aluminum.  World of difference!  I just whacked the Solas on a stump so I switched back to the 3P 21" temporarily.  One ride and even the Admiral was onboard with another prop order ASAP.  So, I switched to a Turning Point for this round- 4P, 19".  It's on the boat now, but haven't had it out, yet.

The big discrepancy between you and I here is that I haven't had any trouble with rpm's.  I've never gotten close to the rev limiter.  I have been at ~48-49 WOT via GPS with good holeshot all the while under 4000 rpm.  I was actually considering going to a 17 for this next prop but decided I'd prefer the Solas vs Turning Point comparison.  The plus to TP props is they're only like $90 since it has a modular hub.  I figure once I sort out my specs, then I will jump to an elite prop.

I really wish there was a boat dyno!  I'd like to know how this motor is actually running.  It runs perfect, supposedly at ~100 hours now- but who knows if I'm getting 220 or 180 hp.  I might consider pulling the motor for a dyno run, but the V-P controls would have to be taken along, and I'm not up for going that far.  Anyway, according to a review I read, it should have planed much quicker stock than it did.  With Smarttabs and 4P prop, I'm planing about as they claimed in the magazine/online article.

This doesn't answer any questions, but does offer some other perspective.  I'm coming to believe that each boat is indeed unique.  Build it the way IT needs to be built.  If you're hitting the rev limiter- go up in pitch.  I recommend the 4P as it offered better bite when cornering and better holeshot.  Going to 4P, I understand it's common to drop in pitch- my experience agrees.  Given that you need pitch, maybe keep the same pitch, just switch to a 4P.  I've done a fair amount of research and found that ultimately it's trial and error.  Tables might give you confidence, but the water tells that tale.  These are expensive lessons- my pockets aren't deep enough to learn in SS.

FYI- Turning Point has a pretty thorough prop selection tool.  It responded with exactly what I came looking to buy.  Their props are unique with 2 different pedal profiles- very anxious to see how it performs.

NRath

sethman919 said:

with weight in it or pulling a tube  the torque is causing a HARD list to the left.

I get it at times, but seems more prevalent when cruising and occasionally when wakeboarding.  I was attributing it to one of the tabs folding and the other one doesn't.  A good curve the opposing direction usually levels it out.  This is what I've come to dislike about the Smarttabs.  I'm working on different setting the tabs left to right.