New bravo III props w/ engine upgrade?

R

rabyers1

Member
Mar 20, 2009
259
Cary, NC
Boat Info
2001 260 Sundancer
Engines
383 Magnum Stroker w/Bravo III
I am in the process of having my 5.7 EFI (hydro-locked) engine replaced with a new 5.7 MPI. The rated horsepower increase is from 260 to 300, about 40 HP. I currently have the 24p props on my bravo III. Anyone have any thoughts on whether will I have to change to a different set of wheeels to maximize the power of this new motor or to keep it from over-revving at the max throttle position? Or any other consequences of this engine swap?
 
Are you getting the 350MAG? I think that engine has a 5,000rpm max, instead of the 4,800rpm you currently have.

You may need to go to a set of 26". But, play around with it first. You're still going through the same set of gears (gear ratio), but you'll be able to rev it up a little more. The extra oomph will give you the ability to turn a bigger wheel w/o sacrificing hole shot, while at the same time gaining a bit on the top end.

Experiment with what you've got, before you go and blindly spend the $1,800 :wow: on a new set, though. Obviously, try and find a used set, if you go that way.

Maybe someone with a '99 - '04 hull and 350MAG can chime in with their gear ratio and prop size. If not, PM me tomorrow afternoon and I'll check my prop/speed charts at work.

Oh, and thanks! Now I have engine envy:smt089. I took my engine out over this past winter and toyed with putting the 350MAG in. I didn't. But, that is my favorite engine - a lot of "bang for the buck".
 
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There have been a lot of BIII prop sets on eBay lately. You might also want to check on whether your current prop set is a standard version, or a cupped version. On the 22P set the Mercruiser SN has a "L" suffix for the cupped props and A40(?) for the standard props. Assuming they are consistent, the L should be used across all BIII propsets. The tricky Mercruiser guys however do not put the suffix on the part number they put on the props!

According to the 2002 Sea Ray Engine & Prop matrix, the 2002 260DA with 350 MAG used 20 pitch cupped props. The engine WOT is also listed as 5000RPM. The prop matrix is blank on gear ratio for that model. You might try and download the 2001 version. I downloaded my copy from Sea Ray before they 'improved' their website, so I don't know if you can still get the prop matrix.

Henry
 
Dennis,

Thanks for the info. Yes, it is the 350MAG. I sure wasn't expecting to have to replace the motor at this point in the boating season. But as I now find that I have to - The MAG is just too irrestable to pass up - even with all the extra cost over just doing a new longblock on the EFI. I am hoping that this new motor will be the thing that keeps me in my 260 for a couple more years and not succumb to the 2' itis that keeps gnawing at me. The motor has just been ordered, so it will be a couple of weeks before I get back on the water. I will PM you then for those numbers as I start to play with my new toy. Do you know what the gear ratio was for the bravo III that they typically put in our set-up from the factory?
 
rabyers1 said:
. Do you know what the gear ratio was for the bravo III that they typically put in our set-up from the factory?
Click to expand...

You know, this is something I should probably have memorized by now. But, no, I don't recall my gear ratio off hand.
 
I've got the same set up. The added HP won't affect your performance enough to warrant changing props. You just may have a slightly different sweet spot. The extra power won't be seen unless you get over 3500. I'd leave it all alone.
 
Thanks for the input Todd. I am certainly hoping to leave it all alone on the BIII end as my boat slush fund will be pretty low for a while after I get the MAG in the ER and running. What I am really hoping for with this new motor is that my cruising sweet spot is attained at a more efficient point in the power curve and therefore I can gain some, even if minimal, improvement in my fuel-burn numbers. I wonder how much torque difference there are between the two motors - I haven't looked at that yet.
 
rabyers1 said:
Thanks for the input Todd. I am certainly hoping to leave it all alone on the BIII end as my boat slush fund will be pretty low for a while after I get the MAG in the ER and running. What I am really hoping for with this new motor is that my cruising sweet spot is attained at a more efficient point in the power curve and therefore I can gain some, even if minimal, improvement in my fuel-burn numbers. I wonder how much torque difference there are between the two motors - I haven't looked at that yet.
Click to expand...

I would guess that fuel burn will be about the same. I think what you'll find is that with the MPI your upper end power band will be improved. Cruising speed RPM may be slightly lower for the same speed you've been used to.

How did your old engine become hydrolocked?
 
:grin:what are your thoughts on the 377 magum from mercrusier? the good the bad and the ugly:smt001
Lazy Daze said:
Are you getting the 350MAG? I think that engine has a 5,000rpm max, instead of the 4,800rpm you currently have.

You may need to go to a set of 26". But, play around with it first. You're still going through the same set of gears (gear ratio), but you'll be able to rev it up a little more. The extra oomph will give you the ability to turn a bigger wheel w/o sacrificing hole shot, while at the same time gaining a bit on the top end.

Experiment with what you've got, before you go and blindly spend the $1,800 :wow: on a new set, though. Obviously, try and find a used set, if you go that way.

Maybe someone with a '99 - '04 hull and 350MAG can chime in with their gear ratio and prop size. If not, PM me tomorrow afternoon and I'll check my prop/speed charts at work.

Oh, and thanks! Now I have engine envy:smt089. I took my engine out over this past winter and toyed with putting the 350MAG in. I didn't. But, that is my favorite engine - a lot of "bang for the buck".
Click to expand...
 
K-9 said:
:grin:what are your thoughts on the 377 magum from mercrusier? the good the bad and the ugly:smt001
Click to expand...

The "good" is it's a well built engine, likes to run, won't argue with you about being up in the RPM band.

As for "bang for the buck", this is where it falls short - now, I'm talking strictly in terms of pricing on a new boat. As far as replacing (longblock, etc) goes, I'm not up on that pricing. This engine is about a $3,500 option over the 350MAG. Not a whole lot of HP for the money, you know? In this situation, I just don't see the benefits. Again, aftermarket or R/R pricing might be different.

It's a bit thirsty, too. But, then what marine engine isn't?
 
OK - spent the afternoon with my mechanic. Went to give a deposit on the 350 MAG to get it ordered from Mercury. Mechanic started showing me other options including both the 5.7 carb. model w/ 250 hp and the 383 MPI w/350 hp from Mercury and some other motors from marinepower, etc. So I told hm to hold off while I ponder this overnight. Pondering has to include the CSR experts. I like the idea of a brand spanking new 350 MPI, but I also find the 383 very interesting. It is a reman. motor, but from what I have been able to read so far - seems to be done very well. It can be had with the standard 1 year warranty or you can add on another two years , for 3 years total. My mechanic says I shouldn't worry about the extra hp and torque (390 ft lbs) having any negative effects on my BIII. He feels like the props should still be something to be looked at after sea trials on either the 350 or 383 - but thinks that with the boat loaded down with fuel, water and family members, the 24p props would be ok, if not optimal. So, should I go with the new 350 MAG or, for a few dollars less, the reman. 383?
 
Todd - to answer your hydrolock question. Hydrolocked is not exactly an accurate description. The whole story is that the last time I had the boat in water in mid-june, I fell on the ramp taking her out and ruptured all the quadricep tendons on my left leg. Surgery followed and I have been out of commission for awhile. In the meantime, the port exhaust manifold had been leaking a small amount of water into two cylinders, unbeknownst to me. Well, the boat sat idle with salt water in those 2 cylinders for about 7 weeks. The engine of course seized badly and I never knew it. I finally went to start it and the starter (new high torque installed this spring) immedately ground a couple of teeth off the flywheel and then just spun freely. Took it in and they discovered the engine's condition when they pulled it to get at the flywheel. :smt089
 
Just checked out the 383 magnum
http://sites.mercurymarine.com/portal/page?_pageid=33,81930&_dad=portal&_schema=PORTAL
reman_383MAG_full.jpg

Wow....got to get me one of those.....especially with the flames on the top cover

Thanks a lot.

Just to be clear this is a vote for the 383
 
rabyers1 said:
OK - spent the afternoon with my mechanic. Went to give a deposit on the 350 MAG to get it ordered from Mercury. Mechanic started showing me other options including both the 5.7 carb. model w/ 250 hp and the 383 MPI w/350 hp from Mercury and some other motors from marinepower, etc. So I told hm to hold off while I ponder this overnight. Pondering has to include the CSR experts. I like the idea of a brand spanking new 350 MPI, but I also find the 383 very interesting. It is a reman. motor, but from what I have been able to read so far - seems to be done very well. It can be had with the standard 1 year warranty or you can add on another two years , for 3 years total. My mechanic says I shouldn't worry about the extra hp and torque (390 ft lbs) having any negative effects on my BIII. He feels like the props should still be something to be looked at after sea trials on either the 350 or 383 - but thinks that with the boat loaded down with fuel, water and family members, the 24p props would be ok, if not optimal. So, should I go with the new 350 MAG or, for a few dollars less, the reman. 383?
Click to expand...

RAB,

STRONGLY consider anything from Marine Power. They are a family owned outfit from Louisiana that are some of the highest quality people that I have ever dealt with.

I had 2: of their 7.4 MPI's in my 39 and any time I had a question, Lee in technical service was always right there with an answer and recommendation.

In regard to the 383 vs. the 350...no contest. The 383 is carrying the 400 cu. in. longstroke crank in a 350 block which means TORQUE...and that's the name of the game in boating. A carburated 383 will be looking over the shoulder pulling away from a MPI 350..truth, fact and real....and a MPI 383...look out big blocks 'cause I'm comming.:thumbsup:
 
From the link posted, the 383 has Hypereutectic Aluminum Pistons, damn, are those NASCAR pistons?

I didn't know so here's a better link - http://en.wikipedia.org/wiki/Hypereutectic_piston
I'm a big fan of the 350 MAG, but the 383 has some impressive numbers. How much cost difference is there between the two choices?
 
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Jeff - the cost I have been quoted for the 383 MPI is about $600 less than what I was quoted for the 350 MPI. However, the 350 is a brand new motor and the 383 is a remanufactured motor. That being said, the 383 reman. program at Mercury seems to employ the same quality control levels as their "new" engine program. I guess these 383 motors are essentially bored-out small block castings that were not originally cast within specs. So, the blocks are assembly line rejects that have now been re-machined to new specs but have never actually been used before. Not really the normal definition of "Remanufactured". I think this is why Mercury offers the same warranty program on the 383 as on their new engines.

I am getting close to pulling the trigger on one here soon.
 
Yeah the 383 is a very good and torquey engine. It's essentially a 6.0L.
I'd consider that package for sure.
 
The 383 equates to a hair under 6.3L. I have no basis to give a recommendation on this one - I really don't know much about it as it is different than the 377 (6.2L). That being said, assuming it's a solid motor, GO FOR IT! If it was me, and I did research and felt it was a good engine, I would absolutely get it as opposed to the 350MAG. Especially at the price you're talking about.

The only downside I could see to the 383 is parts availability. Not that it would be necessarily be hard to get parts, but parts for the 350 are a dime a dozen - very easy to get. There's my 1-1/2 cents. :smt001 Some may argue it's only worth 1 cent.
 
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