Pontoon performance upgrades

[ToonGuy]

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.

They'll put what ever you want on if you have deep enough pockets!

[slingshot]

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???

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???[/quote]


Plenty of ways to get more HP out of your 350 and all just as easy as you car motor. Remember that you marine engine is already worked up due to it's marine application. It's more or less a commercial truck motor which revs much higher than a car motor. Here are some bolt on ideas:

ECU upgrade: I doubt you'll find a pre-made ECU for your particular engine. Not like you would for a stock Mustang GT, Corvette or Challenger for example. You would need a custom tuner like a Bama and use a Dyno and sniffer to get the fuel ratio's right. You can change the tune as you add performance parts.

Cam it up:: You have a marine cam in your engine now but you could get a much taller cam in that marine engines don't really use much HP and torque down in the lower RPM's like cars. I put a Mutha Thumpr cam in my 08 Mustang GT and lost a good amount of low end torque but above 3000 RPM it pulls real hard due to the cam. Figure about a 30 to 50 hp gain on a 350.

Boost it up: Slap a supercharger on that sucker with a cam and now your talking some real HP gains in the area of 100 to 150 or more depending on how strong your lower end is built. Most marine 350's use 4 bolt mains and such that allow you to work over the top end pretty good without rebuilding the lower end but you would have to check with the manufacturer on that. Plus, superchargers are relatively easy to install. Turbos are more difficult due to the exhaust plumbing.

Headers: Lots and lots of marine headers out there from direct replacement to wide open custom thru hulls.

Head work: Pull your heads and send em to a shop for porting and a 5 angle valve job. I had my heads ported on my GT for $600 and it was well worth it. Lots of HP in head work.

Anything on the lower end and you're pulling the motor fur sure. On my old I/O all of the above could be done without pulling the motor but your engine may not be as accessible as mine was.

[dlettow]

Slingshot- these are great suggestions thanks for the help! I looked into an ECU upgrade and it seems like nothing is available for my motor yet since it is a 2011 with catalytic converter. Everyone I spoke with said maybe by next summer. So, that also ruled out the superchargers since the ECU upgrade would be needed for that as well. What about just repowering with the 8.2 HO? Anyone have any idea on the compatibility and costs involved? Would I get any kind of credit for my 350 mag? What kind of increase in top end might I get??

[slingshot]

Slingshot- these are great suggestions thanks for the help! I looked into an ECU upgrade and it seems like nothing is available for my motor yet since it is a 2011 with catalytic converter. Everyone I spoke with said maybe by next summer. So, that also ruled out the superchargers since the ECU upgrade would be needed for that as well. What about just repowering with the 8.2 HO? Anyone have any idea on the compatibility and costs involved? Would I get any kind of credit for my 350 mag? What kind of increase in top end might I get??

Oh how wrong you are about your ECU. That 350 magnum of yours is the most race proven engine made and has more aftermarket parts made for it than any other marine engine. If you want more performance out of your engine simply go with a supercharger. There are many manufacturers for your Merc but I would recommend pro-charger or Whipple. Both of these companies make direct bold on superchargers for your engine. When you buy their supercharger you will send them your ECU and they will send you back a reflashed unit set up for your engine model with their supercharger. bolt on your supercharger and plug in your new ECU and your good to go. You can expect about a 30% to 40% HP increase and it's much cheaper than going with a new 8.2. Plus, there simply is no sweeter music to the ear than the whine of a supercharged V8. Here are their sites and a video of a supercharged 350 MerCruiser (not your engine but you get the idea):

http://www.procharger.com/M_engine.shtml

http://www.whipplesuperchargers.com/pro ... splayCat=1

http://www.youtube.com/watch?v=ljszHEM5lXs

[dlettow]

Well, I'm not sure what to say except that Whipple Industries and ProCharger seems to disagree with you. I spoke at length with Dustin Whipple at Whipple Industries and he said they did not have any options for my motor yet. They do have numerous applications for 2010 and older 350 mags, but the newer motors with the catalytic converters use a different or new ECU and they have not "cracked the code" (those were his words) on this "new" ECU. They were working on it and expected to have it done by next summer. So, I went to ProCharger, they are just a short drive from my home and got the same story. So, my understanding is that while there are a plethora of 350 mag performance upgrades and parts, most of them won't work on my motor until they "crack the code" and are able to reburn or replace my ECU to adjust the programming for the upgraded parts. I don't claim to know a whole lot about all of this, so, I have to rely on what the manufacturers are telling me.

[Bryden24shp]

dlettow, do you have room on the tansom to run through hull exhaust? If you don't, you may as forget doing anything, because you can add all goodies you want, but to push the exhaust through the factory Y-pipe and out the little hole to the lower unit, then through the props. Your not gonna see alot of gain. If you want the engine to inhale more, it has to exhale more, as well. Check with Custom Marine or Stellings to see if any aftermarket headers are available for the 350 mag w/CC's. I think your CC's are built right into the factory manifolds, plus you now have 02 sensors to deal with. EPA takes the fun out of everything. At least we can breath better, right?

[hyper]

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

and a 400 block with a 350 crank is a 377. These are low RPM big torque motors that would work great in a Boat. But them why? slow down and see the world instead of it flying by.

[wedge542]

You might wanta ck and see what that outdrive is capable of before motor mods made, thats a high dollar unit you got but it has its limits, as with new cars today someone is already working on a high hp solution someplace just a matter of time. How fast is your toon now, 45-50 mph, i bet thats a nice ride you got and prob not real loud at topend. Funny how we all here want more speed outta something not realy made for exc speeds, adding toons,bigger motors,strakes,underskin,mega props,when all we had to do from the start was buy a big boat with a real big motor made for rooster shootin mega speed and a sound heard from 2 zipp codes. You might go over to scream and fly and ask around about hp mods but pretty good advise already been wrote. Id like to see a video of yours with sound, bet its a smooth ride and a real joy to drive.I put a bigger motor on mine, goes little faster but so does the gas so now i pull it back to save gas, whatadeal.

[GoFastr]

Go to www.offshoreonly.com to research what you can and need to do for increased performance when referring to V8's and outdrives.