When repowering, is going to larger engines going to give me better fuel consump

[180shabah]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

You will thank yourself for years to come if go ahead and do V8's now. And lets be realistic, a conversion to a single Big block is a LOT of work, and money.

 

[mkast]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

Originally posted by 180shabah:<br /> You will thank yourself for years to come if go ahead and do V8's now. And lets be realistic, a conversion to a single Big block is a LOT of work, and money.

The last time I did this swap, twin 4 bangers in a 28 footer, to a big block. <br />Saturday: remove engines, transoms and sterndrives: fitted and glassed plugs to hull. Sunday: cut new transom hole for the Bravo 1, installed engine cradle and inner and outer transom plates, installed engine, hooked up engine controls and exhaust. By Sunday night the sterndrive was in and aligned. <br /><br />If you go with the twin V8's, cost of both engines, cost of regearing both sterndrives, cost of both new props, you do the math.

 

[DJ]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

If you're going to to repower, I cannot go against suggestions of V-8's as opposed to V-6's.<br /><br />However, you'll find greater satisfaction changing drives too, from Alpha I's to Bravo's or Bravo III's.<br /><br />Your drives are worth something, perhaps the trade up to Bravo's won't hurt that much. Bravos will make a HUGE difference in the way the boat performs regardless of what is in front of them.

 

[Reel Poor]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

Single engine EFI<br /><br />Mercruiser 8.1 375hp brovo III<br />15995.00 + glass work labor and materials, props<br /><br />Mercruiser 8.1 425hp Brovo III<br />19895.00 + glass work labor and materials, props<br /><br />Twin Engines EFI<br /><br />Mercruiser 5.0 260hp Alpha Twin Pac<br />19190.00 + props, No reconstruction<br /><br />Mercruiser 5.0 260hp Brovo III Twin Pac<br />20790.00 + props, Transom plate hole modification<br /><br />Twin engine handeling, power, and security off shore or long distance cruising,,,,,Priceless

 

[tommays]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

They still sell the boat with these power options i dont now how much its changed but if the twin 4.3 option was that bad i think they would have droped it for a 5.0 package which starts with the 30 ft modle<br /><br />496 Magnum® Bravo® III MCM Stern Drive w/Turn Key Start (375 hp - 280 kW) <br /><br />T-4.3L MPI Alpha I MCM (T-220 hp - 164 kW)<br /> <br />T-4.3L MPI Bravo® III MCM (T-220 hp - 164 kW)<br /><br />tommays

 

[bandsaw48]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

Derek,<br /><br />If you're going offshore, keep the twins. The 4.3 is a great and durable engine, very simple and easy to work on. Unfortunately, you're looking at about 1.75 mpg with the 4.3's and less with the V8's.<br /><br />Greg<br />270DA<br />twin 4.3s

 

[bullmercdw]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

As Greg said, If you are going offshore, keep the twins. If one craps out on you, there is still the other to get you home. Call it piece of mind. Just my 2 cents.<br /><br />David<br />Cosmos Mariner

 

[hudman]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

Mercury Remanufacturing “fills the gap” with hybrid 383 sterndrive engine or package<br /><br />By Jeff Van Asten, Mercury Remanufacturing, Business Development Manager<br /><br /><br />In a first-of-its-kind development, Mercury Remanufacturing is now offering a customized non-production sterndrive engine that delivers the power of a “big-block” – without the size, weight, or price.<br /><br />The remanufactured 383 Magnum multi-port fuel injected power-plant is based on a small-block 6.2-litre engine, but features a larger-bore-diameter and longer stroke that provides 325 “propshaft” horsepower with tons of torque. It is designed for medium sized sport boats, runabouts or day-cruisers that can handle a little higher performance, but may not have the room or heft to handle a big-block’s larger size or weight.<br /><br />In an initial sea trial in a 1986 Sea Ray Pachanga, our 383-MAG was installed with a with a Bravo Transom, Bravo I sterndrive (1.50:1 ratio) and swinging a Bravo 24-pitch propeller. It reached a top speed of 62 miles per hour at 5,000 RPM. Which was a huge 20-percent performance improvement over the boat’s original 350 Magnum engine with an Alpha drive and 21-pitch propeller. In addition, at cruising speeds of 30 to 40 miles per hour, the 383 registered a sipping fuel flow rate of only 3.5 to 3.7 gallons per hour. The last comment made by the installation crew was how much quieter the ride was. This is a great, great repower opportunity!<br /><br />The 383 is one of Mercury Remanufacturing’s includes a special two-year factory warranty. It is available as “engine only” (Part No. 865108R11) or as a complete boat package that includes the Bravo transom and drive (Part No. 865108R12). (note: propeller not included)<br /><br />Details regarding the 383 Magnum models are included in the Mercury Remanufacturing 2005 Product Guide (Part No. 90-883299006). Pricing can be located only on MercNet. There is no core charge for these products. In fact, if you order a 383 Magnum, we’ll pay you a $125 bounty if you return the engine core to us. Plus we will prepay the freight to return your old engine or package!<br /><br /><br />May 2005<br /><br /><br />Art: 383 top view installed<br /> (file: 20053835SeaRay[1][1].engine-top.jpg)<br /><br /><br />Photo caption:<br />The 383 Magnum provides big-block power where big-block installation isn’t possible.

 

[jlinder]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

This may be a stupid question, but I gotta ask just so someone can expain why it is stupid.<br /><br />If efficiency is very important, why not diesel? Wouldn't that give better MPG?

 

[Boatist]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

8000 pounds I bet you do not get 2 mpg at your best crusing speed with twins. Go to Sea Ray and ask if they have fuel figures for different engine packages. Also checks the boat test sites and see the fuel figures they have for 8000 pound 32 feet boats. I would sure stick with twins for the added safety.

 

[QC]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

Originally posted by Jack L:<br /> This may be a stupid question, but I gotta ask just so someone can expain why it is stupid.<br /><br />If efficiency is very important, why not diesel? Wouldn't that give better MPG?

Reread my post above about payback or return on investment (ROI) Your post is not stupid at all. Diesel would be the right way to go if this was a commercial application running around 1000 hours a year or more.

 

[Mischief Managed]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

Originally posted by Jack L:<br /> This may be a stupid question, but I gotta ask just so someone can expain why it is stupid.<br /><br />If efficiency is very important, why not diesel? Wouldn't that give better MPG?

Price a diesel engine lately? Yowza. They will also rip an Alpha drive apart from the inside out. Gobs of torque in diesel of that (200+) HP range, and torque is what kills a drive, not HP.

 

[hudman]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

300 hp diesels direct replacement for mercruiser, are are around 17k for the bobtail motor, and require a bravo drive, with heavier gears.

 

[Cptkid570]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

I just don’t know if I like the idea of putting all of that extra weight into the back of the boat by going with the larger engines. From what I gather, the V8 don’t sound like they’d save you much gas (if any). Although, if they don’t work as hard, they may last longer.<br /><br />I looked at searay.com and they offer the same size boat with the twin 4.3s or just the one big engine. They don’t offer it with twin V8’s, so I’m guessing that the 4.3s are plenty of power. I like the idea of 2 engines versus one..especially if you are traveling long distances like you say.<br /><br />My vote would be to go with the 4.3’s again, and if you can afford it, get fuel injected ones, and then you’d save the gas when more at idle/lower speeds.

 

[thegodown]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

I have an 85 270 Sundancer with twin V6's. I run it out to Catalina every month during the summer. My experience is that fuel consumption is greatly affected by the weight. In other words, if I run out there by myself, I can go roundtrip on 50 gals (about 55 miles round trip). Once I load up with family, friends and all their gear for 5 days I almost double my fuel consumption. <br />I was out a couple of weeks ago fishing with the kids and spun the port engine coupler near the breakwater in a strong wind. Without that second engine I would have been in deep doodoo. No amount of savings in fuel would have been worth washing up on the rocks.

 

[bandsaw48]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

Dang Wanchai, 1.1 mpg? What are ya running, 4000 rpm?

 

[Mischief Managed]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

Originally posted by cptkid570:<br /> I just don’t know if I like the idea of putting all of that extra weight into the back of the boat by going with the larger engines. From what I gather, the V8 don’t sound like they’d save you much gas (if any). Although, if they don’t work as hard, they may last longer.<br /><br />I looked at searay.com and they offer the same size boat with the twin 4.3s or just the one big engine. They don’t offer it with twin V8’s, so I’m guessing that the 4.3s are plenty of power. I like the idea of 2 engines versus one..especially if you are traveling long distances like you say.<br /><br />My vote would be to go with the 4.3’s again, and if you can afford it, get fuel injected ones, and then you’d save the gas when more at idle/lower speeds.

Small block V8 only weighs about 63 lbs more than a 4.3 V6.

 

[Cptkid570]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

Wanchi - do the twin V6's give you enough power or do you sometimes wish you had twin V8's?

 

[thegodown]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

If I'm fully loaded (9 people, gear, food and drinks) for a 5 day outing, yes, she is thirsty. <br /><br />The difference between being fully loaded and light is about 1000 RPM to plane and 500-600 RPM to maintain planing speed. I usually make the channel crossing running 24-28 MPH depending on ocean conditions. With a full load it breaks down like this:<br />3400 RPM - 26MPH<br />3600 RPM - 28MPH<br />3800 RPM - 30MPH<br /><br />The last trip I made was August, full load, and the average was 1.28 miles per gallon. <br />Top speed I've seen is 42 MPH at 5200RPM which is not bad for a 10,000 lb boat.<br /><br />The twin V6's seem to do the job just fine. I've been very happy with them. So far I've not needed any extra power.

 

[bandsaw48]

Re: When repowering, is going to larger engines going to give me better fuel con

Re: When repowering, is going to larger engines going to give me better fuel con

Wow! Nine people, when you say fully loaded you mean fully loaded. That sounds pretty good at those speeds. I have yet to incorporate a fuel flow but expect I'm getting about 1.75 at 3100 rpm, 20-21 kts lightly loaded.