Engine ideas involving gas mileage

[perry386]

So the other day my son and I were discussing the gas mileage on our boat as this is the first inboard I have ever owned (a bit shocked at the pump) and we got to talking about ways PCM could improve fuel consumption. The main one we came up with is since the PCM's are built off of the GM platform we were wondering why they don't incorporate the "active fuel management" system that is in the new GM trucks. The system works by deciding how much power and torque is needed for the job and switches between 4cyl to 8cyl based on that. So if you are just cruising down the river with your buddies only going ~20ish mph you would only be running 4cyl which would A)cut gas costs tremendously and B)make the engine much quieter.

The other idea we came up with is to just simply put something like a two-stage transmission into the boats. So it could be geared-out really low when yanking somebody up out of the water but then once it got up to speed it would kick up a gear to lower the RPM's.

What are some of you guy's thoughts on this?

[DanielC]

I am averaging about 3 gallons per hour in my Ski Nautique.
Three gallons per hour in a SUV, or truck going down the road at 60 MPH is pretty close to 20 MPG.

It really takes a lot of energy to shove a boat through the water. A lot of that energy is in the wake you left behind. I do not think there is a lot of gains to be made.

[perry386]

this weekend we spent ~130 dollars in gas which came out to about 3.5 gallons per hour. I guess your right about it not being much different than an SUV. But it still seems like if there is room to improve then why not?

[NautiqueJeff]

There is already at least one boat company using a two-speed transmission out there. They have been around for a few years, and haven't really caught on industry-wide. Must not work as well as they had hoped.

[CradGen2]

Not to be a smarty but the more gas I'm burning i figure the better time I'm having. That said when I had my flighty below we use 20 gallons a day footing. When I lived in Pittsburgh we were good for 70-80 gallons a weekend in all the boat. I had 2.5 boats at the time.

With the weather in New England this year and the wife prego. I have burned but 1 gallon so far. I wish I was in your position worrying about gas usage.

[vision]

There are several options for improving fuel economy that we be welcomed.

Two speed transmission do not work well due the boats serious drag compared to a car. But no reason a CVT would not work.

Integrated motor assist where a battery operated motor gave 15 seconds of instant torque during acceleration would help. This is already available in other marine applications. Using the battery only a few minutes of every hour greatly decrease battery requirements.


ECM programmed acceleration in an econo mode. We do this manually now and you can easily save 1 gal/hr. Since we ave 150hrs/yr, that adds up.

[surroundsound64]

These are TOW boats.

[ally505]

Diesel....... The engines are low speed, high torque & super efficient compared to V8 petrol. The problem is the ski boat industry is led by the US, and diesel cars are simply not as prolific or well accepted as they are in Europe so they will never become mainstream in boats either. The 3ltr diesel engine in my AUdi A6 would power my boat without a problem, 270HP but more importantly 550NM torque. It delivers 40+mpg, 60mph in 6 seconds. I read a while ago that Mastercraft offered the VAG V6 diesel as an option but the pricetag was huge, a small UK boat manufacturer offer the very same engine, cost adder £6000 or about $9000 I believe. A large manufacturer would be able to get the difference down much further I am sure.

[ES]

I am also interested to see how the electric engine evolves. I remember Nautique had prototyped an electric version (230?)...I wonder how that worked out.

[Zach@n3]

Diesel is the wave of the future. No matter if anyone believes it or not. They run forever and return down right great fuel economy. The new engine they are planning on putting into the half ton Dodge would work great in a ski or wake application. Makes around 260 ish hp and 420 ft/lbs. They are going to claim 30 highway and right around 20 city. City mpg is where diesel engines shine over gas. My truck does great on the highway and not so bad in the city but if you can jump from a claimed city mpg of 14 up to 20 in a truck that's where its at. "City" mpg would be more applicable in a boat because they accelerate a lot from a stop and are always under a much greater engine load. If you can pick up economy in that area that's where the $$ will start to show.

The 4 cylinder V8 thing wont work in a boat. There is too much engine load associated with a marine application. My truck will kick out of "eco mode" at the slightest touch of the go pedal. The engine harmonics are way to far off for operation under that much load anyways.

The old Cummins diesel Dodge we had would grab 22 mpg highway (similar to my truck now) but would also return 20 mpg pulling my boat and 17-18 mpg pulling my car. That's where diesel wins.

Plus there are way more economical alternative fuels for diesel engines as opposed to gas. As quiet as diesels are these days that isn't a factor in purchasing. No more smoke or smell either. Lets face it, all the new technology in diesel engines is causing some problems but by the time they actually get one to market in a boat it will be dialed in. Plus with wake surfing being so much more popular now the clean emissions of a diesel is a good thing. Also the lower operating range of a diesel would be better fit for the demands of heavy ballast and pushing the boat through the water not on plane.

[Neverenough]

Ever see the MC with the VW diesel? Pretty cool!! Search on YouTube

[jeepn]

Or this guy putting a Duramax in his x-80

http://www.duramaxforum.com/forum/dm...t-started.html

[swc5150]

The VW / MC diesel was awesome, but it was around $24k to upgrade, so it's no wonder it never caught on. I agree diesel could be the future, but it sure is a slimy, smelly, nasty fuel to be hauling around in gas cans...if you refuel at your dock. I know I'd never get my wife to top off the tank using diesel.

[ally505]

not meaning to be disrespectful in any way. It would seem there is a significantly higher focus on diesel engine technology with the European manufacturers, BMW & VAG lead the way with high the large displacement diesels (namely because they are offering performance cars). 30MPG claimed in an earlier thread would be seen as extremely poor over here. The diesel Audi Q7, a pretty big car and constant 4WD returns more than that without too much fuss.

I cant see how Mastercraft could justify the $24K, it would seem they didnt want anybody to buy it so pushed the price up accordingly.

[swc5150]

Retail on the fancier 550 is about the same, it's just want you want under the hood I suppose? I'm sure putting pencil to paper, that VW diesel came in much less than $24k, but still a hefty upcharge. If it were just a couple grand more than the gas option, they would've sold a lot of them I'll bet. I'm guessing that engine cost quite a bit to marinize, as opposed to just an inflated cost.