Cost of increasing power?

[Paul Perryman]

I have a 2006 Fourwinns Horizon 240 w/ volvo penta 5.0 gxi (270hp). Engine is stressed during watersports or anytime you have a full tank of fuel or more than 4 adults in the boat. My engine has 400 hrs on it and has no known mechanical issues. I would like to upsize my engine to a 8.1L w/duoprop drive (Have SX w/stainless prop) The Fourwinns spec sheet shows Hp to 400, even though 8.1L not an option for new boats.

What is the most economical way to have a new engine/drive installed? Looks like new may run $20k+. Is low hour pre-owned an option? How much of a risk is a used engine? If so, what are best places to look for pre-owned? Can I get anything for my 2006 5.0gxi?

 

[boatnut74]

Re: Cost of increasing power?

The first thing I would try is a smaller prop.

A repower can be very expensive, and switching to a big block there might not be enough room for it to fit. Buying a boat with a bigger engine would probably be more economical.

 

[QC]

Re: Cost of increasing power?

Moving to non-Repair I/O.

 

[Struc]

Re: Cost of increasing power?

+1 on moving to big block will be excessive $$$.

What exactly do you mean by "stressed"?? Need more info on what it is or is not doing.

There may be something else going on. Your boat is pretty new, but are you sure there aren't some other issues like water logged foam going on? Any scales around you where you could get your boat weighed to be sure?

Have you considered installing trim (smart) tabs?

 

[Don S]

Re: Cost of increasing power?

Which drive do you have DP or single prop? What is your wide open throttle rpm with your normal load?

 

[QC]

Re: Cost of increasing power?

It's an SX, Don ^^^^

 

[Don S]

Re: Cost of increasing power?

It's an SX, Don ^^^^

Read the post twice looking for what drive, not sure how I missed it. :facepalm:

A DuoProp lower unit and a set of props will probably do more for that boat than anything else.

 

[QC]

Re: Cost of increasing power?

The only reason I knew was because I looked twice when I missed it the first time. Call it Stealth Drive I/D . . .

 

[Paul Perryman]

Re: Cost of increasing power?

When I say stressed I just mean that it takes longer than I would like to get up on plane. Especially if I'm trying to get up on a slalom ski. This has been the case since it came out of the showroom, so I don't believe there is a mechanical issue. WOT not too far from 5000rpm max, so I think the prop is appropriate. Will I get that much more hole punch with the DP? That would be much cheaper....

 

[QC]

Re: Cost of increasing power?

If you are looking mostly for hole shot, yes, the DP will make a huge difference.

 

[Struc]

Re: Cost of increasing power?

Don't underestimate trim (smart) tabs as well. It's the ultimate cheap fix if it works out for you.

Made a world of difference on my 20' Sea Ray.

 

[rschap1]

Re: Cost of increasing power?

Personally, I would probably look at switching to another boat, but....

Shopping for a decent used motor and drive could be done.
It may take a while, but search long enough and you may be able to get lucky.
If thinking of paying a pro to do it rather than wrenching yourself, you will probably be looking at more labor $$ than what you get the "take out" motor/drive assembly for.

 

[HT32BSX115]

Re: Cost of increasing power?

When I say stressed I just mean that it takes longer than I would like to get up on plane. Especially if I'm trying to get up on a slalom ski. This has been the case since it came out of the showroom, so I don't believe there is a mechanical issue. WOT not too far from 5000rpm max, so I think the prop is appropriate. Will I get that much more hole punch with the DP? That would be much cheaper....

Howdy,


If you're getting "close" to 5000 rpm you're likely "propped" close to optimum.

While you might be a little under powered for what you want to do, 24' boats bave been powered with less power.

Also, you should be adjusting your drive trim for best speed when on a plane. That will not always be the best setting for holeshot......so you might try running the drive down a little lower than where you might run it for for best operation on plane.

A DUO-Prop lower on your drive will absolutely make a hole shot difference!

I had a 460 King Cobra installed in my 1987 21ft Four Winns Liberator (my brother bought it new....I bought it in 2005)

It was pretty fast (60mph) at top speed but was always a real slow dog out of the hole......... So slow that most people including his semi-professional skier (wife) didn't like to ski behind it because it didn't pull her out of the water quickly like a "real" ski boat would!

After I got it I, removed the 460/Cobra and replaced it with a 97 Mercruiser 454/Bravo III engine and (dual contra-rotating prop) drive.

The Mercruiser 454 has approx the same HP as the 460 but the drive made all the difference.

It now comes out of the hole like a ski-boat!

Put a Duo-prop lower on your drive with the correct pitch props and you'll be amazed at the difference in holeshot!

Regards,


Rick

 

[jkust]

Re: Cost of increasing power?

That exact engine was the optional power for my 18 footer and so I've gotta think you are at best marginally powered under the best circumstances. You have an extra 1,320 lbs to push plus I bet at least 10 extra gallons of gas and likely more bodies onboard and a fresh water tank plus a holding tank. I really think this is a case of either moving to a DP, living with it or dealing with it at the margins with different props for your specific use. Was the 5.0 GXI the base engine when you bought it off the showroom?

 

[Paul Perryman]

Re: Cost of increasing power?

That exact engine was the optional power for my 18 footer and so I've gotta think you are at best marginally powered under the best circumstances. You have an extra 1,320 lbs to push plus I bet at least 10 extra gallons of gas and likely more bodies onboard and a fresh water tank plus a holding tank. I really think this is a case of either moving to a DP, living with it or dealing with it at the margins with different props for your specific use. Was the 5.0 GXI the base engine when you bought it off the showroom?

Yes this was the base power. The 5.7's are the optional power. There were 2 models as I was shopping, one with the duo and one without. I was planning on buying the duo, however when I was talking the guy down in price the other one was purchased. (It sat on the lot for the previous 8 months) I couldn't wait to get it in the water so I took the one that was left. It's actually been a great boat besides being a little slower out of the hole than I would like. Adding the duo drive may be a reasonable balance between performance and cost....

 

[tpenfield]

Re: Cost of increasing power?

Yes this was the base power. The 5.7's are the optional power. There were 2 models as I was shopping, one with the duo and one without. I was planning on buying the duo, however when I was talking the guy down in price the other one was purchased. (It sat on the lot for the previous 8 months) I couldn't wait to get it in the water so I took the one that was left. It's actually been a great boat besides being a little slower out of the hole than I would like. Adding the duo drive may be a reasonable balance between performance and cost....

The cost of wanting to get on the water quickly can be expensive, sorry to say. A 24 foot boat with a 5.0 is in the underpowered category.

You might want to consider the cost of getting a more powerful boat (selling yours) versus an upgrade of engine and/or outdrive. Your risk in an outdrive only solution is . . . . What if it is not enough of an improvement?

 

[HT32BSX115]

Re: Cost of increasing power?

What if it is not enough of an improvement?

"More" is never "enough" when it comes to boat HP! Adding a Duo "lower" will be the quickest and easiest (and cheaper than a new engine!) improvement and it'll be very noticeable..... The publication below claims a 30% increase in acceleration........I believe it.

You might have to play with the props a little. Volvo has a "strange" way to designate prop pitch using something other than pitch but it works!

If I was doing it I would refer to the following Volvo Publication:
http://www.volvopenta.com/SiteCollectionDocuments/Penta/Propeller guide/Propeller Guide.pdf

There's also a prop selection tool somewhere, but I would bet that the dealer can tell you "offhand" what they would put on that boat.

In general, you want the engine to turn near the upper MAX RPM at WOT with the boat loaded where you'll run it (load, altitude) on a regular basis.

I just saw a rebuilt DPS-A (lower) on ebay for about $3500...........(I don't know if that's the one for an SX or not)

Not sure if that's a good price or not but I have seen them there from time to time. YOUR SX lower is worth quite a bit too and if you don't want to keep it you can easily sell it to lower your total cost.

I would do the DUO lower now and then down the road, I would upgrade the engine to a 5.7 (or 383 carbureted engine) (you might have to go to the next higher pitch props though)

I'll bet that boat with a 383 and DUO would FLY!

Cheers,


Rick

 

[jkust]

Re: Cost of increasing power?

Yes this was the base power. The 5.7's are the optional power. There were 2 models as I was shopping, one with the duo and one without. I was planning on buying the duo, however when I was talking the guy down in price the other one was purchased. (It sat on the lot for the previous 8 months) I couldn't wait to get it in the water so I took the one that was left. It's actually been a great boat besides being a little slower out of the hole than I would like. Adding the duo drive may be a reasonable balance between performance and cost....

That's a bummer but i've know more than one person that went for the base power plant to be disappointed. There is usually a reason they sit on the showfloor. I know it is consumer driven but it surpises me that even pretty high end boats will offer what will surely be too small of an engine.

 

[Tail_Gunner]

Re: Cost of increasing power?

Here is a viable option that should work quite well

http://www.blueprintengines.com/index.php/marine-mbp3830ct


From there it is a simple as taking the 5.0 component's off...intake...exhaust..everything and bolting them up the the 383 it should be plug and play and if its not im sure the flame will be on... The one thing you need to do is reflash your ecm for the new engine and that can be done with better results than orignal equipment..200 is the cost the only thing you will need to do is get a complete build list from blue print send it to OBD so they can calibrate the tune precisley to the engine..they know what they are doing. Give them a call and inform them of your ideal they will inform you..

http://www.obd2allinone.com/sc/details.asp?item=mefitune

http://forums.iboats.com/showthread.php?t=463926 The thread is a little messy but yes they can retune a EGC controller.

Maybe about 7000 and that engine will get your attentiion.

Ok just tried to do a parts cross reference...Is this a Throttle body in 2006???? Or MPI