Dixie Bandit 170 3.0L 140

[dixie3293]

Hello All,

Newbie here just trying to learn the in's and out's of prop calculation. I currently own a 17ft Dixie Bandit 3.0L 140 Mercruiser. I have a 14.5 x 17 MW on the boat. It pulls me right out of the water (250) on a set of skis great. What i am looking for are those long trips propellers. I would have about 800-1000lb of people/gear on the boat. My current RPM's at WOT can climb almost into the 5200 range which i know isn't good so i keep it around 4600 to only get about 31ish on a good day. I would like to achieve around 45+ mph if possible. I would keep the 17 pitch prop on the boat for those weekends when we wanted to ski and just swap it out in the parking lot. What would get me at my goal speed and a managable RPM 4200ish. I am currently residing in Durham NC so i'm not to far above sea level. Thanks for the help.

PS. if i posted this in the wrong place i'm sorry.


D

 

[tommays]

Re: Dixie Bandit 170 3.0L 140

I have a 17" , 19', 4 blade 20' and a 21"

With my 3.0 and like the 4 blade 20" for trips

The motor needs to be able to make at least 4600 RPM with its current load to stay healthy and be able to get on plane You dont have to run at that RPM BUT it needs to be able to make it


As far as 45 MPH unless your a small person and buy your self with no stuff in the boat that is going to be tough

 

[dixie3293]

Re: Dixie Bandit 170 3.0L 140

How about a 21 pitch with 4 people for a crusing day with about 1000lb in the boat?
The 1000lb would be total weight.

 

[matthewpa]

Re: Dixie Bandit 170 3.0L 140

Unless you are putting a 23p or 25p on that boat you are never going to get there. At that pitch your motor would turn in the low 4000 rpm range and this would be terrible for the motor. I have a 21p with the 140 merc engine and only get 40mph with no one else in the boat at WOT. Your boat is just not designed to go that fast, especially with people in it.
If you look at Stingray's, one of the fastest boats for power provided out there, they are only getting 47-48 out of the Volvo 135hp engine and those boats have a terrific hull design to accomplish this.
You have hit a wall. To get 45 I am afraid you are going to need a new boat with more power or a better design like Stingray.

 

[tommays]

Re: Dixie Bandit 170 3.0L 140

In my general 3.0 experance a 19" would be about the most you could run with that size load

 

[dixie3293]

Re: Dixie Bandit 170 3.0L 140

(I have a 21p with the 140 merc engine and only get 40mph with no one else in the boat at WOT. Your boat is just not designed to go that fast, especially with people in it.)

So how does your 140 Merc run with a 21 pitch and about 4 people? I will mainly run around with 2 (me and my tiny gf) but the occational 4 is possible. If i can get to plane and turn 4500rpms to cruise from one end of the lake to another i will be happy.

Thanks
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[matthewpa]

Re: Dixie Bandit 170 3.0L 140

It is not snappy to plane at all, it does drag a little. 4500 rpms for the 3.0L is not cruise either, it is WOT balls to the wall. It is not recommended to run that engine at WOT for extended periods of time. When I set the RPMs at 3000 I am at 22mph, 3500 is 27mph, 4000 is 33mph. That is with an empty boat. WOT with my normal load is 35mph max.
I am actually moving to a 19p prop because I occasionally need to move people to the front of the boat to get on plane with that 21p. I personally would not recommend the 21p at all, way to tall for that engine. 27-30 is a nice cruise speed as well.
It sounds as if you want to go fast, you have the wrong boat and engine to do that.

 

[dixie3293]

Re: Dixie Bandit 170 3.0L 140

I guess i am trying to squeeze water out of a rock here! I am just trying to achieve the best speed with that little 4 banger. High octane is 3.81 a gallon now here in Raleigh-Durham NC. I have a buddy who has a 19 so i'll try it out to see how it does. mabye i will get a used / rebuilt 21 for those days there are two of us in the boat on our long trips.

Anybody else out there with the same setup that can give some advice please feel free.

To those who have advised your all a blessing

Thanks
D

 

[dixie3293]

Re: Dixie Bandit 170 3.0L 140

Ok ALL!

I'm back after a great weekend on the lake. I went from a 17 pitch to a 19 pitch and I can still turn 5200 Rpms. Does this mean i can easily go to a 20 pitch?

Thanks again
D

 

[HotRodHaven]

Re: Dixie Bandit 170 3.0L 140

I have a 1986 Dixie Bandit 170 with a 3.0 and matched it with a 14.25 x 23 High Five (5 blade)and am running the same top speed as the 14.25 X 21 3 blade. It also jumps right up on plane. TV

I'm back after a great weekend on the lake. I went from a 17 pitch to a 19 pitch and I can still turn 5200 Rpms. Does this mean i can easily go to a 20 pitch?

Thanks again
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