Bravo 3 Re-prop - Hill Marine 4x4 vs Mercruiser 4x3 vs Mercruiser XR 4x3

NorthwestChap

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With the new engine in my boat, I am just a bit over the rev range at WOT. I am looking at some options for the replacement props. I will have the current props re-worked as backups, but would really like some of the benefits of the added blade or two. Most online info is not very current, so looking for some ideas or comments.

1997 Chaparral 2330, 5.7l Bravo 3 with 2.2 ratio

Current props 26P, Gear ratio 2.2-1, RPM -5100, MPH - 52, Slip - 9%

Engine specifies a rev range of 4600-5000.


Thanks
 

jimmbo

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May 24, 2004
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You are only 100 rpm too high. Once the wife and Mother in law are aboard you should be well within the 4600 - 5000 range. Others may differ, but I see no benefits to adding an another blade on each prop, just kills top end. With two props you already have lots of blade area as your 9% slip figure shows
 

NorthwestChap

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Mar 7, 2011
Messages
224
You are only 100 rpm too high. Once the wife and Mother in law are aboard you should be well within the 4600 - 5000 range. Others may differ, but I see no benefits to adding an another blade on each prop, just kills top end. With two props you already have lots of blade area as your 9% slip figure shows

​jimmbo, I have neither of those to worry about (wife or MIL). That test was with my sons onboard for a day of fishing. Fuel was midrange, about 35-40 gallons.

The RPM wasn't the only consideration. Since we go on lengthy trips with the boat, having a backup set in case of an errant ding or two would be nice. The touted benefits of the 4x3 and 4x4 props of increased hole shot and reduction in midrange fuel consumption, with little to no loss of top end (and in many cases, an increase) makes them attractive as well.
 

alldodge

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Been doing lots of testing with different props, pitches, rakes and blades. Other folks have tried the 4x3 and have found good results, but that said the guy who was using them decided to go back to 3x3. These are all cruisers like mine , which yours id the mid size runabout. I'm currently running 22-4x4 Hill marine props.

BBlades which is one of the main folks for props, also sells Hill props. That said, go straight to Hill to get the props. BBlades and other charge a restock fee, but get them from Hill, there is no restock fee. Also if you want to change out, just pay the shipment back and they pay to ship you a new set. Also don't bother of cleaning them up, they do that for you at no charge. They also sell the 3x3's and others.

Guess the end point is Hill will take care of you, no matter which way you want to go, so if anything else, they are worth talking to.

Now two things about your rpm's.
Make sure your tach is accurate, it might show an rpm, but it may be off.
If you have an MPI 5.7 then the top rpm is 4600-5000, but if its an EFI throttle body then its only 4400-4800
 

NorthwestChap

Petty Officer 1st Class
Joined
Mar 7, 2011
Messages
224
Been doing lots of testing with different props, pitches, rakes and blades. Other folks have tried the 4x3 and have found good results, but that said the guy who was using them decided to go back to 3x3. These are all cruisers like mine , which yours id the mid size runabout. I'm currently running 22-4x4 Hill marine props.

BBlades which is one of the main folks for props, also sells Hill props. That said, go straight to Hill to get the props. BBlades and other charge a restock fee, but get them from Hill, there is no restock fee. Also if you want to change out, just pay the shipment back and they pay to ship you a new set. Also don't bother of cleaning them up, they do that for you at no charge. They also sell the 3x3's and others.

Guess the end point is Hill will take care of you, no matter which way you want to go, so if anything else, they are worth talking to.

Now two things about your rpm's.
Make sure your tach is accurate, it might show an rpm, but it may be off.
If you have an MPI 5.7 then the top rpm is 4600-5000, but if its an EFI throttle body then its only 4400-4800


​Hey AllDodge,

​Thanks for the info. Spoke with Ron Hill yesterday. Great guy. I am leaning towards the 4x4's in the same pitch (26), as Ron's experience has been a slight drop in RPM with the equivalent pitch prop. Still not positive though. Searching the internet for performance on comparable boats is limited at best.

The high speed runs were done with a digital tach attached to the engine, with GPS for speed. My analog tach was surprisingly accurate, within 10-20 RPM. The engine is a carbed GEN+ engine 325 HP with RPM range of 4600-5000.

​So, are you happy with the performance of your 22 Hill's? Was there much of a difference between the 3x3's (if that is what you had originally)? What were your performance/maneuverability gains or losses?

Thanks
 

alldodge

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Staff member
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Mar 8, 2009
Messages
40,582
​Hey AllDodge,

​Thanks for the info. Spoke with Ron Hill yesterday. Great guy. I am leaning towards the 4x4's in the same pitch (26), as Ron's experience has been a slight drop in RPM with the equivalent pitch prop. Still not positive though. Searching the internet for performance on comparable boats is limited at best.

The high speed runs were done with a digital tach attached to the engine, with GPS for speed. My analog tach was surprisingly accurate, within 10-20 RPM. The engine is a carbed GEN+ engine 325 HP with RPM range of 4600-5000.

​So, are you happy with the performance of your 22 Hill's? Was there much of a difference between the 3x3's (if that is what you had originally)? What were your performance/maneuverability gains or losses?

Thanks

If you can turn 5K rpm with the carb motor it must be a new build.

My boat is a 11K pound signal engine barge. My slip was in the 16 to 17 percent slip, and with hill I'm in the 11-12 percent. Currently having the hull paint sanded off and I'm going to paint with VC performance epoxy for this season.

Started with 24-3x3, then 26-3x3, then 22-4x3 cupped, but not XR models, they were custom. My hole shot is nice (500 hp at the prop). The Hill props reduce the slip better then any others. None of the 3x3's would bring the boat out of the hole like the 4x4.

I also learned some issues with my boat which changed my initial thoughts.
Before: as speed increased I would trim up a tad more, rpms went up, and so did speed but only slightly
Now: as peed increases, don't trim up, as rpms went up, so did speed.

Prior my rpms was going up and so was speed, but this was more slip. Found out what was best for the boat performance.
Start with cav plate straight and level with bottom of the hull. Go through the rpm range and document speed and rpm. Change prop and do same thing, this gives you the baseline for the hull.

After this is know, then you can try trimming up more
 

NorthwestChap

Petty Officer 1st Class
Joined
Mar 7, 2011
Messages
224
If you can turn 5K rpm with the carb motor it must be a new build.

My boat is a 11K pound signal engine barge. My slip was in the 16 to 17 percent slip, and with hill I'm in the 11-12 percent. Currently having the hull paint sanded off and I'm going to paint with VC performance epoxy for this season.

Started with 24-3x3, then 26-3x3, then 22-4x3 cupped, but not XR models, they were custom. My hole shot is nice (500 hp at the prop). The Hill props reduce the slip better then any others. None of the 3x3's would bring the boat out of the hole like the 4x4.

I also learned some issues with my boat which changed my initial thoughts.
Before: as speed increased I would trim up a tad more, rpms went up, and so did speed but only slightly
Now: as peed increases, don't trim up, as rpms went up, so did speed.

Prior my rpms was going up and so was speed, but this was more slip. Found out what was best for the boat performance.
Start with cav plate straight and level with bottom of the hull. Go through the rpm range and document speed and rpm. Change prop and do same thing, this gives you the baseline for the hull.

After this is know, then you can try trimming up more

It is a new build. It performs quite well.

Thanks for the info. I'll definitely take what you learned and experiment with mine a bit. The increase in hole shot will be appreciated, as I've added a bit of weight with the restoration.
 
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