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5.7 monsoon with supercharger?


yotaisgame

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I have dreamt about this too but after consulting those in the know I would not consider supercharging the stock indmar. Heads, bottom end and rods will probably survive but NA pistons are wafer thin and would be the achilles heel in a marine application. If, on the other hand, you were prepared to pull it down and make appropriate changes to pistons and clearances then I would do it. Particularly if you are running at altitude which is why I would assume you are considering the suggested. When it is all said and done supercharging is probably the most cost effective power upgrade when compared to optional engine prices. Down here they are obscene.

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Stock Monsoon will not do well, in the long run, with a SC. You'll gut them.

The Hammerheads are a little better, but not sure I'd trust them beyond the mains and crank either.

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Longevity is a concern. I'm not at altitude but with 9 people in the boat, mls full plus maybe 200 in the pnp I can't get it up to speed to wakeboard and that's with a torquey prop. The bigger motor would be nice.

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Do you know anybody that can supercharge a monsoon? I called a few places but nobody would touch the motor with the cat. I would love another 100-150hp for surfing but would need a bigger gas tank to go with it!

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I'm sure you could do a very mild boost level, like 4-5 psi, as long as you could get it properly calibrated for it.... That might be the hardest part. Is there a company that does custom tuning for these? Probably have to pull the engine to get it tuned on a dyno. I'm thinking it would cost too much to bother with...... Finding a boat with more ponies might be cheaper. Or, prop down, and deal with a lower top speed.

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^^^^ this. assuming you could do the sc install yourself, and assuming you could get the ecm tuned at a reasonable price, at teh end of the day you are probably out of pocket 4-6k? And your boat will probably be worth less than when you started. Certainly any remaining warranty will be gone, and to the vast majority of the buying public, there will be a "modified" strike against the boat.

Crazy as it sounds, it probably makes more economic sense to sell this boat and buy a used/new one with the motor you want.

All that said, if you do the mods, please post lots of pics! We live for that kind of thread on here.

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You don't have to pull the boat to dyno tune it. It actually might be better to tune it on the water while running it at a realistic load.

I suppose you could have somebody modify the exhaust manifolds for an EGT sensor. It wouldn't be easy with a jacketed manifold, I wouldn't think. Also, can you use an exhaust gas analyzer in water?

I wouldn't be surprised if there is an easy way to get all of those readings for a proper tune..... I am just not "up to speed" on marine equipment for that sort of thing. I have only ever heard of them being tuned on a bench Dyno.

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The 5.7 works well with a torque prop, but more hp equals a bigger wave. That's all. With the 5.7 & 2419 my surf wave fully loaded is big enough for 2 people to surf at the same time, but it makes me wonder how much fun another 150hp could be :) For wake-boarding you really don't even need the power of the 350. If you need more than that you are probably sponsored and aren't buying your boat anyways. For cruising and tubing, the 5.7 is a great balance of power and fuel economy.

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I suppose you could have somebody modify the exhaust manifolds for an EGT sensor. It wouldn't be easy with a jacketed manifold, I wouldn't think. Also, can you use an exhaust gas analyzer in water?

I wouldn't be surprised if there is an easy way to get all of those readings for a proper tune..... I am just not "up to speed" on marine equipment for that sort of thing. I have only ever heard of them being tuned on a bench Dyno.

It could be tuned without EGT. A wideband O2 sensor and other readings would be fine. EGT is nice to have, but not a requirement.

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The 5.7 works well with a torque prop, but more hp equals a bigger wave. That's all. With the 5.7 & 2419 my surf wave fully loaded is big enough for 2 people to surf at the same time, but it makes me wonder how much fun another 150hp could be :) For wake-boarding you really don't even need the power of the 350. If you need more than that you are probably sponsored and aren't buying your boat anyways. For cruising and tubing, the 5.7 is a great balance of power and fuel economy.

I'm not that good at wakeboarding but I still like a big wake because it's fun getting big air. I consistently run my Monsoon 330 at its capacity and many of my friends with Monsoon 350s also run theirs at capacity.

Hell I was on a 24MXZ with a 550 once and we ran so much ballast it almost couldn't get on plane.

Big wakes are FUN!

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We see these posts every couple of months, but no one ever pulls the trigger. Ever.

It's daunting and I suspect that most people find it better to manage the problem with ballast configs and props because it's just SO much easier.

It's honestly a good idea though. Even if you were to pull the motor, rebuild it beefed up, put on a supercharger and tune it, you'd probably still be well under the 550 upgrade. And with a built motor, you could easily make 5-600hp reliably.

Edited by boardjnky4
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We see these posts every couple of months, but no one ever pulls the trigger. Ever.

Biggest issue is the tune/chip that you would need to make it work. Its not like cars where folks are selling a kit for the engine that includes some sort of tuner or chip to make it all work. I could put a supercharger on my 5.7 Hemi in an afternoon by just writing a check and having a box show up with everything I need in it. The MEFI stuff just doesn't have that sort of support.

Edited by oldjeep
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It could be tuned without EGT. A wideband O2 sensor and other readings would be fine. EGT is nice to have, but not a requirement.

AFAIK, exhaust gas temps are probably the most important measurement to properly tune an engine at WOT. Sure, a wideband, will give you some fine tuning info, and is extremely valuable for part throttle tuning. But it will not tell you if you are going to melt the engine down at a 13.0/1 AF ratio at WOT.

So, I guess, sure, you could go extremely conservative and get it in the ballpark. That's not really what I meant by "properly tuned". I wouldn't put my $10k boat engine in the hands of a tuner that uses "horseshoe and hand grenade" practices, to dial it in....... But that's just me.

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Super chargers on boats are very common in the hot boat scene so it certainly can be done. I'm sure you could always eliminate the cats to make it work.

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We see these posts every couple of months, but no one ever pulls the trigger. Ever.

Then they learn it only take one nut and a puller to remove the prop. Done in less than an hour.

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AFAIK, exhaust gas temps are probably the most important measurement to properly tune an engine at WOT. Sure, a wideband, will give you some fine tuning info, and is extremely valuable for part throttle tuning. But it will not tell you if you are going to melt the engine down at a 13.0/1 AF ratio at WOT.

So, I guess, sure, you could go extremely conservative and get it in the ballpark. That's not really what I meant by "properly tuned". I wouldn't put my $10k boat engine in the hands of a tuner that uses "horseshoe and hand grenade" practices, to dial it in....... But that's just me.

Plenty of tuners tune cars every day without EGT. It's not a deal breaker and certainly not a horseshoe and hand grenade practice. Of course it allows you to get a more accurate tune.

Biggest issue is the tune/chip that you would need to make it work. Its not like cars where folks are selling a kit for the engine that includes some sort of tuner or chip to make it all work. I could put a supercharger on my 5.7 Hemi in an afternoon by just writing a check and having a box show up with everything I need in it. The MEFI stuff just doesn't have that sort of support.

http://www.obd2allinone.com/mefitune.asp

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Plenty of tuners tune cars every day without EGT. It's not a deal breaker and certainly not a horseshoe and hand grenade practice. Of course it allows you to get a more accurate tune.

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They do?!? I have never witnessed that.... im glad I don't work with those tuners.

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