prop choice for B 3 on 1997 271 Fastech


L

larry1954

New member
1997 271 Fastech 454 Magnum, single engine - have changed the Bravo 1 26P to a Bravo 3 2.2:1 ratio 20P duo prop. It seems underpropped - I reach 5000rpm at about half throttle (WOT is supposed to be 5150rpm, I think). I am looking at a Hills Signature 4x4 24P. Does 24P sound about right? I am not looking to maximize top end speed and would sacrifice something of that for good hole shot. But do want best fuel economy. Boat is used as a general pleasure boat, so we sometimes pull a wakeboard rider, etc. We could never pull a wakeboard rider with the Bravo 1 26P - I simply could not keep it on plane at a reasonable wakeboard riding speed (about 20 mph).

With the Bravo 3 20P the boat planes very easily, and is much better for pulling a wakeboard rider, but it does not have much real speed. To do 60km/hr you will be doing 5000rpm and I would think that it would be better for the longevity of the engine, and perhaps also fuel consumption, to bring that rpm down, if that could be done without adversely affecting the boat's performance for water sports.

I have contacted Hills Marine and they recommend the 24P. It sounds about right, but just wanted to check with others before proceeding. For example what prop does a 260SS with B3 usually have, since that might be comparable to my case?
 
The 454 Mag (Carb or EFI) WOT should be 4600 - 5000 rpm. The rev limiter (if it has one) would kick in at 5150

If the original B1 drive was a 2.2 ratio then I would agree that the 24P-4blade B3 would be the way to go

The good thing with Hill is they will swap you props as many times as needed until your happy. Only cost is return shipping.

I have a set of Hill 22P-4blade B3 props that I really like, but had to remove once final rebuild of motor and hull was done due to over reving. I'm now using Merc B3-26P
 
larry1954 said:
1997 271 Fastech 454 Magnum, single engine - have changed the Bravo 1 26P to a Bravo 3 2.2:1 ratio 20P duo prop. It seems underpropped - I reach 5000rpm at about half throttle (WOT is supposed to be 5150rpm, I think). I am looking at a Hills Signature 4x4 24P. Does 24P sound about right? I am not looking to maximize top end speed and would sacrifice something of that for good hole shot. But do want best fuel economy. Boat is used as a general pleasure boat, so we sometimes pull a wakeboard rider, etc. We could never pull a wakeboard rider with the Bravo 1 26P - I simply could not keep it on plane at a reasonable wakeboard riding speed (about 20 mph).

With the Bravo 3 20P the boat planes very easily, and is much better for pulling a wakeboard rider, but it does not have much real speed. To do 60km/hr you will be doing 5000rpm and I would think that it would be better for the longevity of the engine, and perhaps also fuel consumption, to bring that rpm down, if that could be done without adversely affecting the boat's performance for water sports.

I have contacted Hills Marine and they recommend the 24P. It sounds about right, but just wanted to check with others before proceeding. For example what prop does a 260SS with B3 usually have, since that might be comparable to my case?
Click to expand...

My 260ss with 502/ B3 2.00:1 gears runs nicely with the 26p set on it.
Our Boats are probably similar weights.
2.2 gears with 20p sounds way under propped. [emoji848]. Id think 26 possibly 28 if your rev limiting at half throttle.
So many variables but reaching rpm spec at wot is what I would use as the guide.
 
Thanks for that, AllDodge & PJ. I told Hill Marine about your 260SS, PJ, with the 26P, but they still think the 24P. Is your 26P a 3x3 or a 4x4? If yours is a 3x3 then perhaps that would make the difference, so that a 24P 4x4 could be about equivalent to a 26P 3x3? Hill Marine seemed quite sure that the 24P 4x4 would be the best choice.
 
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