Baja 232 Boss.. 454 Carb and M+ 21P?

[BajabossJD]

Hey guys..

I have a 1997 Baja Boss 232...with a 454 Carb'd and a Bravo 1 spinning a 21p Mirage Plus. I finally got the engine running strong and I was told it was rebuilt with about 15 hours on it when I bought it..

I hop onto plane very quick and it seems I climb to the upper end of the rpm range fast..almost like I'm running out of gear in a car..( although I dont run it wide open) it easily hits 4800-4900 rpm on the tach (too high)..Gps is around 55..

Would a Mirage + 25p help me lower those rpms and gain some speed? Engine feels strong.

Thanks,

Joe

 

[Bondo]

Re: Baja 232 Boss.. 454 Carb and M+ 21P?

Ayuh,... The 23" would be the next logical step,...
But,... It Might be able to pull the 25"....

What's yer target rpms at Wot,..??

 

[BajabossJD]

Re: Baja 232 Boss.. 454 Carb and M+ 21P?

Thanks for your response..

Based of what I can see..its rated for WOT 4200-4600.. I just dont want to mess up and buy the wrong prop.. at $350 they are not cheap. I would like to cruise at a lower rpm..Currently..3000rpm shows about 31mph..4800..about 55mph..

Thanks,

Joe

 

[Philster]

Re: Baja 232 Boss.. 454 Carb and M+ 21P?

No way a 21p prop is right. Too small for sure. 23p in Mirage or Bravo format and I bet you see more speed, because these props will definitely tame the RPM a bit and you'll be able to trim out more with a bigger prop*. The bigger prop is pushing you farther with every turn. Yes... more speed for sure. I'd be stunned if you didn't get 5 MPH out of it.

*This is the single most under-valued part of running a larger, but proper prop that will see you get more hull out of the water in a performance boat such as yours.

 

[BajabossJD]

Re: Baja 232 Boss.. 454 Carb and M+ 21P?

Thanks for your response! I really need to get rid of this 21p.. Do you think a 25p would be too much? The local prop shop said they could pitch my 21 to a 23..for about $150.. Not sure what I should do. I want to get one, and hang on to it for a while. I would love to see 60+mph..

Thanks again,

Joe

 

[Philster]

Re: Baja 232 Boss.. 454 Carb and M+ 21P?

Yeah, for the 25p question, let's start here:

When you are wide open throttle, she runs at 4800, or is there more? What load was this with? Lightly loaded, at WOT throttle, you would ideally get right to the 4600 rpm redline. That'd be sweet.

I really think the 23p is the way to go if you were outta steam at 4800 rpm. I'm am being pretty honest, because I have a 25p Mirage prop that I am wanting to move.

I think she'll be a 60 MPH boat with the 23p. All numbers say so.

Seems to be lots o' love for the Bravo props. But Mirage is fine too. Both Merc products. I think for classic V bottom stern drive with big blocks, the consensus is becoming Bravo. Would not be surprised if a 24p 4-blader got recommend by someone, or me, if you had more RPM left in your first description of the issue.

 

[tpenfield]

Re: Baja 232 Boss.. 454 Carb and M+ 21P?

Hey guys..

I have a 1997 Baja Boss 232...with a 454 Carb'd and a Bravo 1 spinning a 21p Mirage Plus. I finally got the engine running strong and I was told it was rebuilt with about 15 hours on it when I bought it..

I hop onto plane very quick and it seems I climb to the upper end of the rpm range fast..almost like I'm running out of gear in a car..( although I dont run it wide open) it easily hits 4800-4900 rpm on the tach (too high)..Gps is around 55..

Would a Mirage + 25p help me lower those rpms and gain some speed? Engine feels strong.

Thanks,

Joe

I've got a boat that is the next size up (24 ft) and I am running the Mirage 21P with the 454 Mercruiser. So, a 23P would be good, and you will knock off about 400-500 RPM. I cannot tell from your post if you were at WOT with 4900 PRM's, but you were probably close. If you had the 454 Magnum engine, then a 25P would be worth a try.

 

[Philster]

Re: Baja 232 Boss.. 454 Carb and M+ 21P?

Also, a 25p would be good for 70 MPH, but the carbed 454 isn't going to push that along at 70, so the more I think about it and after reading tpenfield's post, 23p would be perfect and a little over 60 MPH.

 

[BajabossJD]

Re: Baja 232 Boss.. 454 Carb and M+ 21P?

Some great info here guys.. thanks.

I was showing 4900-4950 WOT with the trim tucked a little bit. I confirmed this with my friend who was on board. We were lightly loaded..20 gallons of fuel.. two people. I was suprised to hear a 23p will knock off that much RPM..thats a good thing. It sounds like the Bravo props seem to be 1p higher than the comparable Mirage + props. I guess I can look for a 23p and if I do need more down the road, the prop shop can work it to a 24 or 25..


I really wish I knew the history on this boat. The engine is impossible to know what I have.... It just seems stronger than a stock 310 power plant..

Thanks guys,

Joe

 

[Philster]

Re: Baja 232 Boss.. 454 Carb and M+ 21P?

Well, it's just that, based on experience, unless the 454 is worked it's not going to push you along at 70 w/ a 25p, and the math around the 25p indicates 70 MPH, give or take an MPH.

If you had a 502 squooshed into that engine bay, she'd be turning a 25p good for 70+. There were some boats of your size from Scarab and Stingray that were setup just like that: 23-24' with a 502 jammed inside and bolted to the same drive with a 25p 3-blader and they were good for 70+ all day and night.

Most props are compromises unless they are labbed/tuned by a shop anyway.

Plus... You were about as light as a boat can get with 20 gallons of gas. Is that a 65 gallon tank? 20 gallons is pretty much empty! Less than 1/3 full is empty where I am from!