Pontoon performance upgrades

[dlettow]

Having been a motorsports nut for many years I have noticed a sort of disconnect when it comes to being able to increase performance in the marine industry. In the car and motorcycle world you can swap out exhausts to a freer flowing system, improve air intake, add performance chips to alter the computer controlled processes of fuel/air intake. As a result you can experience substantial gains in HP and in some instances even fuel economy. But, in marine applications there seems to be little to no performance mods you can easily perform to squeeze the performance out of our engines that the EPA and other gov't entities have choked out of them. Does anyone know of such mods that I am not aware of???

[margaritaman]

You could get a toon with an inboard and soup it up.

[dlettow]

I have a Mercruiser 350 mag sterndrive, what do you mean by "soup it up"?

[Bamaman]

You could always swap your 350 for a hopped up 383 engine, free flowing heads, better induction system, beefed up valve train. Think how fast the boat would accelerate with momentary use of a nitrous system?

But, I don't know if your current outdrive system could sustain a 7000+ rpm motor with such heavy horsepower. It'd sure sound great, however.

[The_Hellbilly]

I thought the same thing. A few years ago, I began looking for something for my Honda, but never found anything legit.

[Bryden24shp]

Start by ugrading your ECU. Eric at Simons Motorsports can 'reburn' Mercury, Yamaha and Suzuki outboard ECU's and some Mercruiser sterndrive ECU's. My 225 Verado had the 310 upgrade. Cost was $850.00, for 85 horsepower, which is cheap horsepower. My Mercruiser 502/425HP in my Baja was upgraded to 525 hp. Yes, your constraint is your lower unit. If you are running a Bravo One, your generally ok to about 600 horsepower. You'll cook an Alpha or a Bravo III with anything above 400. Headers, Cams, go with a Pro-Charger. All kinds of goodies to play with. How fats your wallet?
Then you can start looking at your pontoons and transom on the boat. Some areas can be blueprinted to make the hull flow better in the water. Transom deflectors to force the bow down, when running bow lifting props will help lift the whole boat out of the water. Notch the bottom of the center pontoon under the transom and add a flat pad about 2 foot long under the motor pod, reduces alot of drag from the back of the center pontoon. If your gutsy and good with a welder, you can have alot of fun! Offset side of doing performance mods is ride quility and durability. You always give up something to gain something.

[margaritaman]

I have a Mercruiser 350 mag sterndrive, what do you mean by "soup it up"?

I'm no mechanic but if your motor is like a car motor you should be able to increase hp with bigger pistons.

[Bamaman]

You can certainly bore out the engines, however there's limitations to what a "small block" Chevy can be bored out to. The 383's are so popular, but many bracket drag motors are 412 cubic inch motors running alcohol.

Big blocks often go into the Cigarette type offshore racing boats, but they're just too heavy. Tritoon boats are relatively light for their size, and aft weight really matters.

Has anyone ever put any of the 300 hp Mercury Pro XS factory race motors on a tritoon? I'll see them from time to time on our lake on Allison and Bullet bass boats. They redline @ 7,500 rpm's--and really sound mean at high rpm's. I have a professional fisherman friend that was scared to death @ 105 mph GPS in an Allison.

[GregF]

One of my mechanic buddies swears the ECU is the only difference between a 40 and a 60 merc big foot. I still think there may be a throttle plate restrictor in the 40 and 50.
Yamaha takes the exact same block and squeezes 70 hp out of it.
They do have a different intake tho.

[dockholiday]

You can certainly bore out the engines, however there's limitations to what a "small block" Chevy can be bored out to. The 383's are so popular, but many bracket drag motors are 412 cubic inch motors running alcohol.

Big blocks often go into the Cigarette type offshore racing boats, but they're just too heavy. Tritoon boats are relatively light for their size, and aft weight really matters.

Has anyone ever put any of the 300 hp Mercury Pro XS factory race motors on a tritoon? I'll see them from time to time on our lake on Allison and Bullet bass boats. They redline @ 7,500 rpm's--and really sound mean at high rpm's. I have a professional fisherman friend that was scared to death @ 105 mph GPS in an Allison.

So who make the 383's I am seeing on pass time. I know plymouth use to have a 383 but pretty sure this is something like a crate motor. The one's I have seen look really strong. So what is the background on the 383's and exactly who make em.........

[Bmac]

Use to make 383's outa 350's using a longer stroke 400 crank (strokers). Could also make one using the 400 block with a 350 crank,but the 400 small blocks were hard to keep cool as they were siamese bore. So we stroked out the 350's to gain more cubes.

[pond tuuunes]

I think a chevy 350 w a 400 crank is a 383. JT

[GregF]

It's been a long time since I was a hot rodder but isn't that going the wrong way. I thought if you wanted a high rev motor you wanted a shorter stroke and a bigger bore. It was emission control that stroked the 327.

[Bmac]

For the most part that's true. What your really after in a stroker is the higher/longer torque curve.

[Bamaman]

And in a marine environment, a longer torque curve is what's really needed.

Speaking of marine engines: I was looking at the Shootout at LOTO this weekend, and some of the big Cigarette type boats had the most incredible power plants in them--as much as 1600 horsepower. I think many people overlook the Mercury Racing division and the incredible powerplants they build. They put out engines every bit as tricked out as anything coming out of NASCAR, however they're allowed to have superchargers. Too bad such craftsmanship is not seen in regular run of the mill pleasure boat engines.