2003 182 BR? 3.0L big enough???

[fwebster]

Here's a comment from the peanut gallery..........

You guys can hose each other ad infinitem over thermal losses, internal frictional losses, and other technical minutia, but don't forget the original question.......is a 3.0L enough motor for a particular boat?

Sea Ray is the subject of the question and I can tell you that Sea Ray will not release a boat that isn't safe or that is so under powered that it will not perform to some minimum level of performance. Simarly, Sea Ray will not produce a "hot rod" with so much power the hull is dangerous. Between the 2 extremes there are sometimes optional engines offered. I have never heard a complaint about having too much power, but you will hear complaints about there not being enough power for some situations.

My own view is that it is a mistake to buy a boat with minimum power configuration. They are seldom more fuel efficient because it takes a lot more throttle at an inefficient part of the engine's power curve to achieve the speeds and thrust desired. A larger engine choice is usually more satisfactory because it deliveres what the owner needs at a lower throttle setting in a more comfortable rpm range for the engine and the boat's occcuants.

And, the above discussion does not take into consideration the lower resale value or quality of investment differential of a boat with the smallest engine choice, nor does it address the additional maintenance/repair cost of a engine that must run full out most of its life. The owner's overall satisfaction with a boat is driven by a lot more engine efficiency.......comfort? security? maneuverability? noise?

I don't care if its gas or diesel, and I don't even know if the boat is question was offered with more then one engine........just give me the biggest engine available every time out.

OK.........y'all can continue now.

 

[BiffStroganoffsky]

I'm not talking about a dyno.:smt100

Ok, I can see where I read the wrong graph as you were referring to. Are you referring to a graph for an internal combustion engine? That would explain the shallow bell because all ICE is very inefficient. However, being that both the 3.0 and 4.3 are ICE, they would share the same graph. The only real difference is the 4.3 allows you to convert more potential energy into work over the same time period. Still, there is only the same amount of potential energy in a gallon of gas and both engines will convert said gas into approximately the same amount of work.

 

[springer3]

I agree with your statement about using twice the fuel at idle, but we are not talking about at idle.
This does not look like an efficiency curve to me...:smt101

We are talking about fuel consumption, where you make the claim that a large engine can match the consumption of a small engine. I have agreed with you that there are specific examples, but the 3.0 is not one of them, and in any apples to apples comparison, it will not even be close. When you talk about an efficiency curve, is this thermal efficiency, or overall efficiency? I tried to break that down into elements just to try to find where you are misguided.

You have agreed there is double the consumption at idle where any boat spends some time. This is progress. I will help you on the next question:

No-wake idle: both engines are still closed-throttle and turning idle RPM. Let's say 5 hp useful energy getting produced to turn the propeller. Friction loss is about 2 hp inside the 4-cylinder, and always double inside the 8-cylinder. The 4-cylinder the engine must produce 7 HP to cover 5-hp out the shaft, and the internal losses. The 8-cylinder is up to 9 hp to cover the shaft power plus friction loss. The 4-cylinder will have lower pumping losses because its engine controls had to boost the power up to a higher percentage of full power. Also the 4-cylinder is on a higher part of its thermal efficiency curve because it is making a higher percentage of full output.

Bottom line: we are still burning twice the fuel, and boats do need to run in no-wake idle near shorelines, in marinas, and past bridges.

Can you please try the next case by yourself?

Thank you!

 

[keokie]

Springer,

I understand the word problem.

But again, as Berth mentioned, I am talking about planing. I know the larger engine will use more fuel at idle. I have measured that as well. However, for the vast majority of boat owners, the greatest fuel use by far will come from running on plane.

When running on plane, pumping loss, friction loss, and thermo-efficiency differences between the two motors is insignificant.

As Biff pointed out as well you get a certain amount of work from a gallon of gas. When you run an engine under heavy load, the efficiency reducing properties of the larger motor become too small to matter.

Think of it this way. Honda and Ford now recommend 5W20 oil in many of their vehicles. It reduces internal friction and therefore increases efficiency. This works in a car. Try substituting 5W20 in a boat. As you are rapidly taking away future hours of operation, compare the fuel economy while on plane to what it was with straight 30 weight. It won't make any difference in economy.

In the example you give of going to a 4.3 from a 3.0, are you talking about the exact same boat?

My examples are with the exact same boat. I've done it numerous times with numerous exact same boats. The engine builders I refer to have done it for decades and are probably in the hundreds. And yes, they do Lake tests before and after with instruments. They know when to discount a motor that is not running properly, or when an outdrive or gear ratio has been changed.

Leave it to Frank to try to get this back to the original question. I didn't think anybody was looking anymore.

dpvandy, sorry for the partial high-jack. Thanks for not jumping on us. But the topic of fuel consumption can be a deciding factor for some.

 

[berth control]

Springer - I get your stupid word problem. The real problem is that you don't understand what I am saying about an engines efficiency over it's power output range. I told you what to put on the axis, where is the graph?

I also agree that the 3.0 would use less fuel at no wake speeds. Nobody is talking about no wake speeds. We are talking about running on plane for prolonged periods of time. That is where the bigger engine may, and probably will get better fuel economy.

I know some people that can never be convinced of anything, except that they are always right, even when they are wrong. Now I know one more.....

 

[springer3]

The reason I cannot agree is that I am informed on the subject and you are not. I have agreed there are examples of poorly-engineered small engines that waste gas, especially at high power settings. The efficiency curve for any well-engineered engine peaks at or near peak power, and does not decline much as RPM is increased past peak power.

If you work the word problem to the full-power case, the 8-cylinder engine finally does better. It is at half throttle, and therefore burning 10% more fuel to overcome pumping loss. It is also burning 5% more fuel because it is lower on the thermal efficiency curve at half power. The 8-cylinder engine is also burning 5% more gas on friction loss. Therefore, the 8-cylinder burns 20% more fuel for the same fun. Average the fuel usage over the typical outing cycle for a sport boat, and the 8-cylinder engine burns 50% more fuel even before you start to go faster. Going faster costs serious money, and I expect most V8 boat owners spend twice as much on fuel as the owners of 4-cylinder boats even if you normalize for boat size. They can afford it, so more power to them (pun intended).

The 3.0 liter GM marine engine is called the "Iron Duke" because of its legendary ruggedness. It sips fuel relative to even the 4.3 liter V6. It is an excellent choice for a small pleasure boat used for family fun, especially if the family is on a budget.

I have tried to inform, and I hope provided a basis for informed opinions. This is my last post as I think the subject is worn out. You may have the last word.

 

[berth control]

I had a 16' four winns with an iron duke in it for a little over a year. I went through Michigan's "chain O lakes" with it alongside my dad who was in his 18 footer with a 4.3, both carburated engines. He used less fuel and we went the exact same place at the exact same speed. Both of us used about 40 gallons, so it was a long enough trip to get accurate readings, and both boats had about the same load in them, but his is 2 feet longer and wider than mine was.

This is not "it feels like my new boat with the bigger engine uses more gas", but documentation of an actual trip that I was on.

 

[keokie]

This is interesting. I don't agree with all the analysis or explanations, but I would imagine these guys know how to read simple instruments. Anyway, it's worth a look.


Power Shopper
By Charles Plueddeman
Photographed by Don Rutt
February 2004

Which Engine — and How Much $$$$ — is Enough?



“Buy all the horsepower you can afford.” This old chestnut has been passed on from generation to generation of boat buyers. When faced with a long list of power options, reach deep into your bank account and buy the biggest engine you can, because—as conventional wisdom goes—no one has ever wished he or she had less power. • With more power, you not only get a higher top speed, you also get better cruising economy. A big engine can supposedly throttle back to get the same speed a smaller engine has to work harder for. The bigger engine is even said to last longer because it works under less stress.•This bigger-is-better concept of horsepower seems so logical it’s gone unchallenged for years. And in the Carburetor Age, it may have been based in fact. But today, in the Fuel Injection Age, the average V-8 has had a dramatic boost of output and economy. So it occurred to us that maybe the old convention should go the way of the wooly mammoth.

Big, Bigger, Biggest
To put the theory to the test, we set out to compare the performance of three engines in the same boat. Four Winns provided us with three identically rigged 26' 250 Horizons and then let us use its testing facility in Cadillac, Michigan.

The 250 Horizon is offered with nine different engine/drive combinations from MerCruiser and Volvo Penta. A daunting array. Sticking with Volvos, we started with the base engine, a 280-hp 5.7Gi. For midrange power, we chose a 320-hp 5.7GXi. And to cap off things, we picked the maximum power available, a 375-hp 8.1Gi. Each engine was mated to a DuoProp drive.

Before testing, we weighed each boat without fuel. The two boats powered by the 5.7-liter engines (the 280 and 320) were within 10 pounds of each other. The boat powered by the 375-hp engine weighed about 235 pounds more, which is about what it should be according to Volvo’s specifications.

The price of the 250 Horizon with our base 280-hp package is $53,285. Moving up to the 320-hp rig raises the price by $2,232. And you’ll pay an extra $5,577 over base for the 375-hp setup.

Another way to look at is, if you buy the 280-hp engine, you’re paying $190/hp. Buy the 320-hp engine and you’re paying $173/hp. Go for the 375-hp option and it’s $157/hp. Seems like the bigger engine is already proving to be a bargain.

The New Wisdom
We tested each boat with a light and a heavy load. The light load included 15 gallons (90 pounds) of fuel and one 175-pound passenger. For the heavy load, we weighed down the boat with 50-pound lead-shot bags to simulate a full load of fuel (450 pounds) and eight hefty passengers (1,850 pounds).

Our first test was for acceleration from zero to 25 mph. To our surprise, there was little difference in performance between the 280 and the 320 for both light and heavy loads. The 375, however, was a relative rocket out of the hole when light, and more than acceptable when heavy. It had a substantial 24 percent improvement over the two other engines in light trim and 30 percent in ballast.

Next, we measured top speed. Again, the difference in performance between the 280 and 320 was minimal. The extra 40 hp of the 320 delivered only about 1 mph more when both light and heavy. The 90 extra horsepower of the 375 produced a 7.3-mph increase in top speed over the base engine when light and 6.7 mph when loaded down.

Finally, we measured fuel economy by running at 30 mph, 40 mph, and wide open, with both light and heavy loads. Naturally, we measured fuel consumption to get gph and mpg. But we also plugged in a diagnostic tool to read percentage of throttle opening. This allowed us to confirm or refute the notion that a big engine can be throttled back to achieve better cruising economy.

At 30 mph with a light load, each of the three engines achieved almost identical miles per gallon, and each throttle was open between 30 and 33 percent. The mileage dipped with a heavy load but remained close from engine to engine, as did the percentage of throttle.

At 40 mph, we got similar results both in terms of mileage and throttle. In each instance, there was little difference among the three engines.

At wide open throttle, the big 375 sucked down more than 30 gph and achieved only 1.7 mpg. Compare this to the 280’s 22.0 gph and 2.2 mpg, and the 320’s nearly identical 22.7 gph and 2.1 mpg.

Our throttle percentage readings were a revelation—and meant the death of a universal boating truth. When throttled down to cruising speed, the bigger engine used just about the same amount of fuel as the smaller ones. How could this be? Simple. It takes a certain amount of fuel to produce a set amount of power, regardless of the engine’s size. And it takes a set amount of power to move a boat at a particular speed. In other words: It’s not the engine’s size, but the power it’s producing that determines fuel consumption.

In retrospect, this makes perfect sense. But what didn’t tally was why the 320-hp engine didn’t use more fuel when wide open (at maximum power) than the 280. If it was making more power, why didn’t it use more gas? And why was its performance in every situation so close to that of the 280’s?

The Price of Fudge
The answer: Even though there is a 40-hp difference on the printed spec sheets, there isn’t that much of a difference in real life.

Here’s an important lesson when you’re shopping for a boat. Manufacturers allow themselves a fudge factor when publishing horsepower ratings. An outdated (at least, to our way of thinking) industry agreement permits a leeway of plus or minus 10 percent in published horsepower. Sometimes an engine model may have less than its rated power, and sometimes it may have more.

Unofficially, from Volvo, the 280-hp 5.7Gi engine is “very strong 280 hp…it’s actually closer to 300 hp.” For the record, Volvo told us that the 320-hp 5.7GXi needs 20 to 30 hours of break-in time to reach its full power. Our test engines each had only three hours on them. This may explain why the 5.7GXi just barely achieving its advertised 320 hp, and why there was so little difference between the two in our tests.

The 320-hp 5.7GXi was introduced to fill the horsepower void created when General Motors dropped its popular 454-cid V-8, usually rated at 300 to 310 hp. This left a big gap between the 280-hp versions of the 5.7-liter and the 375-hp 8.1-liter engines.

Volvo Penta’s solution was to pump up the 5.7 with roller rocker arms having a 1.6:1 ratio that mimic the lift and duration of a high-performance camshaft. The engine computer was also reprogrammed, and different intake and exhaust manifolds fitted.

Faced with the same dilemma, MerCruiser chose to stroke out the 5.7 to 6.2 liters and install a camshaft designed to boost midrange torque. This may be a more comprehensive approach, but it also makes the engine more expensive. Someone (you) has to pay for the extra work of dismantling and rebuilding the entire engine. On the Four Winns’ price sheet, the 320-hp Merc MX 6.2/Bravo Three lists for about $1,000 more than the 320-hp Volvo 5.7GXi/DP.

Pony Up?
We may have unraveled an old conventional wisdom about choosing power and introduced you to the whims of horsepower designation, but one fact remains the same—it costs a lot of money to go only a little faster.

If you want more performance from a large runabout or small cruiser, the only way to get it is to opt for the big-block engine. Anything in the middle is not likely to be worth the cost. In this specific case we might be able to justify spending the $5,500 (or about $800 for each additional mph) for the 375-hp 8.1Gi if we knew we were going to be heading out with a lot of passengers on a regular basis.

So that leaves the 280. Usually we stay away from a manufacturer’s base engine. It’s often there as a price-point teaser—low on price but way too low on usable horsepower. But in this case, Four Winns offers a realistic starting package. For us, the base “very strong 280” provides all the power we need.

 

[Scottbenson]

Or you could just go out and buy the 3.0 liter and have fun on the lake.

 

[Marco1]

I know this is a bit old, but it seems that this test gives it to the bigger engine

Sea Ray 182 Bowrider Test Result Highlights

• Top speed for the Sea Ray 182 Bowrider is 47.9 MPH (77.1 KPH), burning 14.7 gallons per hour (GPH) or 55.64 liters per hour (LPH).
• Best cruise for the Sea Ray 182 Bowrider is 23.0 MPH (37 KPH), and the boat gets 8.83 miles per gallon (MPG) or 3.75 kilometers per liter (KPL), giving the boat a cruising range of 207 miles (333.13 kilometers).
• Tested power is 1 x 190-hp MerCruiser 4.3L MPI.

Sea Ray 180 Sport Test Result Highlights

• Top speed for the Sea Ray 180 Sport is 43.3 MPH (69.7 KPH), burning 10.2 gallons per hour (GPH) or 38.61 liters per hour (LPH).
• Best cruise for the Sea Ray 180 Sport is 23 MPH (37 KPH), and the boat gets 5.54 miles per gallon (MPG) or 2.36 kilometers per liter (KPL), giving the boat a cruising range of 105 miles (168.98 kilometers).
• Tested power is 1 x 135-hp MerCruiser 3.0L.

 

[quailrunner]

May be beating a dead horse, but...

I've driven both boats, a 185 - 130hp (13 years old) - my cousin's boat, and mine; a 185 - v6 - 190 hp (4 years old) for one season. I like the v6 a LOT better. First, the overall vibration and noise at any given speed is seriously less. Second, pulling my cousin on one ski in her boat causes the stern to swing with every cut; in my boat, the effect is almost not there at all. The 190 can carry more people/gear while behaving well. The top speed difference does not really matter; its affected by specifics of the load so much that her boat can beat mine easily if I'm carrying more people. Bottom line; I like the bigger engine a lot more (don't ask me about fuel; I'm on the lake to have fun and I just hand over the CC and don't worry about it; if there's a difference, its not going to be enough to break the bank).

 

[Black180BR]

Holy cow that was a good read....brought back from the dead, but a good read no doubt!!