Wakesurfing Ballast on Swim Deck - Air Intake issue?

[swatski]

I was changing the air filters today and finally decided to take a good look at the air intakes - which happen to be under the stern storage, on both sides (sort of):

Interesting, in the new 240/242 the STRBD side vent is only the Blower/Exhaust, PORT is the fresh/cold air intake.


Here is a close-up (outside) of the fresh/cold air intake - PORT side:


And a close-up of the Blower/Exhaust outlet - STBRD side:



The fresh/cold air vent opens up inside the engine compartment - on top/PORT side:
(I peeled the foam for better view, the silver is RAAMmat insulation in my boat)


Now the Blower/Exaust vent DOES NOT open inside the engine compartment - it is completely enclosed with a mount for the blowers/hoses - top/STRBD side:


So - basically - the only air intake from the outside is under the PORT side stern storage!
(Both blowers suck the air out of the engine compartment and exhaust under the STRBD stern storage)

When we wake surf, we will typically run with extra ballast on the swim deck/platform (in addition to the built-in 3 x 800lbs in center and rear lockers). For surfing regular side - that extra ballast would sits on the PORT side of the deck. Usually 1 or 2 bags 550lbs each, staggered.




Are the bags obstructing the air intake?! At any rate - they are are not helping!
We have a semi-decent wake, but if I'm starving the engines of air, this can not be good.

I thought I would share. There has been some talk of making form-fitting bags for the swim deck, I think @0627Devildog has been working on some. Well, air intakes may need to be a consideration. It just never crossed my mind, until today.

@gmtech16450yz - any ideas on CAI mods?


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[haknslash]

When I was looking at wake boats at the boat show this past weekend I noticed many have their air intake vents in front of the windshield. It would be nice if Yamaha had similar vents instead of relying on the underseat back intake area.

 

[swatski]

When I was looking at wake boats at the boat show this past weekend I noticed many have their air intake vents in front of the windshield. It would be nice if Yamaha had similar vents instead of relying on the underseat back intake area.

Kind of what I'm thinking. There is plenty of room on the top of the bulkheads (under the hull cap/in the stern) to fit an intake with an airfilter.



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[swatski]

Actually the bulkheads in the stern storage are perfect place for air filter (pod), just need to be vented - also perfect location. Any water ingress is not an issue as it is a wet compartment by design and drains to the swim platform.
I already have my Johnson (ballast) pumps there, two per side, plenty of room for air pods and easy routing into the engine compartment. I'm kicking myself for not doing it earlier, it just seems like a totally obvious mod.



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[gmtech16450yz]

Haha. Yeah, overly obsessive mod minds think alike! I'm in the middle of another one of my "mod fests" on my boat and was actually staring at the air intake system also. I do agree that the engine compartment could use some better airflow, but don't worry about starving the engines, that would be hard to do. Those giant 4 cylinder air pumps are going to pull air from wherever they can, and sealing off the entire engine compartment tight enough that it would effect power wouldn't be likely in my opinion. But yes, positioning that wake bag a little differently would probably be a good idea.

I'm finished with my exhaust re-do, the Moroso mufflers are in and it all turned out pretty clean. Now I'm re-doing my dash panel since I wasn't thrilled with it when I made it. Instead of making another one out of aluminum, I'm using white marine hdpe board. I'm also adding 4 gauges and 4 switches on the panel to solve some little issues I had with the boat operation. I'll make a separate thread when it's all finished. Basically the gauges are all about not having any indication of water flow through the engines unless you want to hang your head over the side and check the outlets constantly. I've had two situations so far that have resulted in flow problems, one actually got all the way to an overheat light before I had any indication there was a problem. Hopefully the gauges will prevent that.

Back to your CAI... It's a decent idea that I may also pursue. I decided to not do anything on the intake side of my engines right now because I really don't know what effect the exhaust mods will do. If the exhaust is super quiet and the intakes are screaming loud, I'm going to work on quieting them too. That's why I don't want to dive into the idea of any CAI or engine compartment airflow mods right now. But after my next time on the water I'll know if I need to!

The other thing about mods like CAI is I would need to see data before I decided to do anything. I have a suspicion that intake air temps are higher than they need to be on these engines, but how high, I have no idea. That step would involve logging engine data. That's a slippery slope, like we've talked about before. If I see data I don't like, can I change it? Not without either a lot of work or a lot of money. So for now, I'm happy with dumping cheap regular gas in these engines and letting them run the way Yamaha set them up. Being a California boat, it gets really good fuel mileage and I even like the cat converters because you don't have to smell the exhaust. It's a HUGE deal for me not tuning these engines or even monitoring something as basic as intake air temps, but for now it's ok with me. I'll let you know if I do end up coming up with a better way to get air flowing through the engine compartment though. The first hurdle to solve would be doing it without letting all the engine noise out of the engine compartment. That's a big issue. Your idea of a CAI at the anchor light position would be easy, but also would be loud. VERY loud.

 

[gmtech16450yz]

When I was looking at wake boats at the boat show this past weekend I noticed many have their air intake vents in front of the windshield. It would be nice if Yamaha had similar vents instead of relying on the underseat back intake area.

That was actually one of the things I thought about, getting fresh air from the front and letting it go along the sides of the hull and into the engine compartment. I had a situation last time out that made me re-think that idea though. We were idling on one engine. It was super quiet and I kept hearing engine noises at the FRONT of the boat. I opened the port side front seat compartment and the engine noise got louder! I then opened the door under the windshield on the port side and I also could hear the engine! F that! So of course that's part of my current mods, to close off and insulate any engine noise from getting out of the engine compartment and traveling up the sides of the boat.

So I think this might be a place where the Yamaha engineers were thinking and came up with a good approach to the problem. Those air vents in front of the windshield would certainly transmit noise from the engines out of them. So sitting in the front seats could be pretty loud because of it. How often is somebody sitting on the rear deck of a Yamaha boat when it's going WOT? Not likely. So where does that engine compartment noise end up going? Out the back of the boat where nobody is sitting or can hear it. And not only that, it's "muffled" by having to come out under the rear seat cushions.

So thinking more about your's and swatski's thoughts, there may be room for improvement on engine compartment airflow, but unless you want to introduce other issues, it's going to be tricky. I'm almost thinking instead of re-designing the system, simply improving on the blowers might be a better answer. If you could have high cfm blowers that were quiet running at all times the engines are running, you could get plenty of airflow without letting a bunch of engine noise out in the process. Hmmm. lol. I might have an idea...

 

[gmtech16450yz]

Geeeeeez you guys are gonna make my head explode!

Ok I just found out that the stupid loud blower fans in our boats put out an amazing 135 cfm. lol. For as loud as they are, that's cr@p. I've hated those stupid fans since I first turned the key on in my new boat and heard them howl! I've tried running them in series instead of parallel, I've tried putting dynamat on them, now I'm going to try throwing them in the garbage!!!

I have a couple SPAL 5.2" fans sitting in my shop that put out about 5 times the cfm and are probably quieter. I'm going to either put those or something even bigger into my boat. My plan is to run them in series whenever the engine is running and then be able to turn them both on in parallel with the switch on my new dash panel. Both of them running in series shouldn't be very loud at all, and that way the engine compartment will get nice fresh air all the time. And when I want super turbo airflow to really cool things down in there, I'll have 1,100 cfm of airflow going through the engine compartment at the flick of a switch.

swatski, (Wojtek was it?) If I decide to run the fans as blowers instead of suckers, I would think it might actually put a tiny bit of positive pressure in the compartment instead of working on a negative pressure to pull fresh air in. It's not going to be anything measurable, but in theory, it "should" help to make sure the engines are getting plenty of fresh air.

Not exactly the direction you were thinking of, but that's the amazing thing about people sharing ideas, they almost always get better with more input and thoughts! Thanks!

 

[swatski]

Geeeeeez you guys are gonna make my head explode!

Ok I just found out that the stupid loud blower fans in our boats put out an amazing 135 cfm. lol. For as loud as they are, that's cr@p. I've hated those stupid fans since I first turned the key on in my new boat and heard them howl! I've tried running them in series instead of parallel, I've tried putting dynamat on them, now I'm going to try throwing them in the garbage!!!

I have a couple SPAL 5.2" fans sitting in my shop that put out about 5 times the cfm and are probably quieter. I'm going to either put those or something even bigger into my boat. My plan is to run them in series whenever the engine is running and then be able to turn them both on in parallel with the switch on my new dash panel. Both of them running in series shouldn't be very loud at all, and that way the engine compartment will get nice fresh air all the time. And when I want super turbo airflow to really cool things down in there, I'll have 1,100 cfm of airflow going through the engine compartment at the flick of a switch.

swatski, (Wojtek was it?) If I decide to run the fans as blowers instead of suckers, I would think it might actually put a tiny bit of positive pressure in the compartment instead of working on a negative pressure to pull fresh air in. It's not going to be anything measurable, but in theory, it "should" help to make sure the engines are getting plenty of fresh air.

Not exactly the direction you were thinking of, but that's the amazing thing about people sharing ideas, they almost always get better with more input and thoughts! Thanks!

John - I hate those little factory blowers with passion! Not only are they loud and pretty much useless as far as moving air, they also provide for significant static noise over my tower ICON8s... Really want to rip those noise maker little things off of the boat. But I won't - don't want to get a citation if anyone ever looked.

I may end up just opening some vents between the engine compartment and the wet storage compartments in the back. I'm installing SS conical air filter pods (replacing factory boxes) and was toying with an idea of running nice silicone hoses/tubes up to stern wet storage comps with filter pods mounted there.
So - I guess you (of all people!!!) just convinced me not to do a mod... (!).
Wojtek

 

[swatski]

@gmtech16450yz John - and one more thing. Not to change the topic, but it is kind of related to air flow.

I believe @blacksapphirez has experimented with covering up the engines with a soundproofing sheet. Also, in the past @Ronnie has constructed a 'box" around the engines with soundproofing insulation. @blacksapphirez reported good results if I'm not mistaken, and I really like the approach because of its simplicity and robustness - one could fit a lot of foam on top of the engine compartment, and the sides.

The question is - would you think that just covering the top of the engines (and going around the sides) with some thick soundproofing foam (thick sheet, 5-10" or so) is a good idea? If the air flow is not obstructed, engines being water cooled anyway - and as you pointed out being fairly strong air-sucking pumps, it may be a very effective soundproofing solution - also super easy. I like to think maybe even memory foam would be a good material for that - acoustically absolutely superior, form fitting, and fire resistant.

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[buckbuck]

@swatski
I tried using sound reducing sheets around my engines years ago. While it did dampen the noise a bit it raised my operating temperatures so I scraped the idea.

 

[swatski]

@swatski
I tried using sound reducing sheets around my engines years ago. While it did dampen the noise a bit it raised my operating temperatures so I scraped the idea.

Thank you, very helpful!
Darned.

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[haknslash]

It would be funny if this is related to the "my engine won't crank when ballasted/listed over"?

I doubt it as the increased water box pressure theory seems far more plausible but the rising operating temps makes me wonder. Our issue was the port side not cranking and that was the side we list

 

[swatski]

It would be funny if this is related to the "my engine won't crank when ballasted/listed over"?

I doubt it as the increased water box pressure theory seems far more plausible but the rising operating temps makes me wonder. Our issue was the port side not cranking and that was the side we list

I know, right??!!!!
Albeit those re-start issues would always pop up on the surf side only. But still..., that could have something to do with it, definitely crossed my mind.

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[Jgorm]

One thing I've learned over the years is that reflection of sound is key for quiet operation. One 90° angle (not too sharp) in duct work works for wonders for sound. I had a 20,000cfm fan in my dyno shop that was loud as f. Like open header loud. I installed some of my "muffler" pipe onto the intake side and it made an unbelievable difference. The "muffler" was 30"id with perforated metal, 2" insulation, then sheet metal (34"od). There were 2 90° bends (about 6' radius). The giant muffler worked so well I could dyno 600+hp cars just 20' away from million dollar condos and we never got a complaint.
Baffle boards also work wonders without creating any restriction. Here is a crappy drawing.

 

[Jgorm]

Before I installed a couple feet on the intake side.

 

[gmtech16450yz]

One thing I've learned over the years is that reflection of sound is key for quiet operation. One 90° angle (not too sharp) in duct work works for wonders for sound. I had a 20,000cfm fan in my dyno shop that was loud as f. Like open header loud. I installed some of my "muffler" pipe onto the intake side and it made an unbelievable difference. The "muffler" was 30"id with perforated metal, 2" insulation, then sheet metal (34"od). There were 2 90° bends (about 6' radius). The giant muffler worked so well I could dyno 600+hp cars just 20' away from million dollar condos and we never got a complaint.
Baffle boards also work wonders without creating any restriction. Here is a crappy drawing.

Dead on! Isn't sound and vibrations cool to work with and try to control? I love it. I've modified so many exhaust systems over the years I've learned a ton. That and my brother happens to be a professional musician and album producer that has taught me a bunch on controlling sound in a recording studio environment. There are definitely ways to attenuate sound and also ways to spend a bunch of time, money and complexity to not effect the levels at all.

The dual Spal fans are in my boat already. They are quieter and move 5 times the air on full 12 volts (running parallel) than the stupid little Rule blowers . On 6 volts they are whisper quiet and probably still move more air than the stock blowers on 12 volts. Tomorrow I'll wire them so that whenever the engines are running the fans will run in series and when I flip the dash switch they will run in parallel to move a lot of air through the engine compartment when needed. As far as safety goes, that setup will be safer than the stock setup by far. I honestly think the engine compartment blowers should have gone away when carburated engines did, but that's another issue. lol.

I've also done a bunch more sound deadening in the engine compartment, I'll post some pics later. Yes, you CAN reduce engine noise without compromising engine airflow or cooling. I've basically made the engine compartment in my boat look like a recording studio. haha.

 

[swatski]

Dead on! Isn't sound and vibrations cool to work with and try to control? I love it. I've modified so many exhaust systems over the years I've learned a ton. That and my brother happens to be a professional musician and album producer that has taught me a bunch on controlling sound in a recording studio environment. There are definitely ways to attenuate sound and also ways to spend a bunch of time, money and complexity to not effect the levels at all.

The dual Spal fans are in my boat already. They are quieter and move 5 times the air on full 12 volts (running parallel) than the stupid little Rule blowers . On 6 volts they are whisper quiet and probably still move more air than the stock blowers on 12 volts. Tomorrow I'll wire them so that whenever the engines are running the fans will run in series and when I flip the dash switch they will run in parallel to move a lot of air through the engine compartment when needed. As far as safety goes, that setup will be safer than the stock setup by far. I honestly think the engine compartment blowers should have gone away when carburated engines did, but that's another issue. lol.

I've also done a bunch more sound deadening in the engine compartment, I'll post some pics later. Yes, you CAN reduce engine noise without compromising engine airflow or cooling. I've basically made the engine compartment in my boat look like a recording studio. haha.

PICTURES PLEEESE!

I totally dig what you guys are talking about! I recently experimented with stuffing empty ballast bags in the back of the bulkhead/rear compartments - just filled with air - to fill the space completely. I only did this once. I was very surprised... it worked really well - in blocking noise coming through the rear (under seat) compartment.

Very simple test - run the boat with or with out ballast bags (empty, just blown up with air until they fill the space) and then open up/lift the seat up:
- there is a lot of noise coming through with an empty compartment
- the noise is substantially reduced/muffled with air-inflated bags in there!

I couldn't believe it, frankly. Now - it does make more sense based on what you guys are talking about.
I may consider making it a permanent feature, I have a bunch of spare older ballast bags hanging around. It is easy mod, and those bags don't add any weight!

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[gmtech16450yz]

Nope, you're not crazy, it makes perfect sense that filling that compartment with air filled bags would stop the engine noise from propagating.

To quiet that sound from traveling up the sides of the hull I added foam to the panels. I literally had to crawl inside the rear compartments to get to the screwed in panels at the far back. Good thing I'm kinda small! I took the panels out and put foam on each side of them. I ended up with the walls between the engine compartment and those side compartments being completely isolated by sound deadening foam. I also added the missing section of carpet on the sides of the hull between the front and rear compartments. Again, without anything on that fiberglass, that space acted like a giant sound box.

BTW I found out something cool about that space on the port side of the boat... On the 212's, the entire Bimini top fits inside that space! So like now, during winter when I doubt I'll ever need the top, I can still have it in the boat just in case. I put it in through the rear seat opening and pushed it all the way up towards the front compartment under the windshield. It fit!

 

[swatski]

To quiet that sound from traveling up the sides of the hull I added foam to the panels. I literally had to crawl inside the rear compartments to get to the screwed in panels at the far back. Good thing I'm kinda small! I took the panels out and put foam on each side of them. I ended up with the walls between the engine compartment and those side compartments being completely isolated by sound deadening foam. I also added the missing section of carpet on the sides of the hull between the front and rear compartments. Again, without anything on that fiberglass, that space acted like a giant sound box.

I am so glad you don't think I'm crazy, at least in this particular instance. I'm bracing myself - for work on stuffing and covering those bulkheads... What a back-breaking itch-inducing job. But I, too, believe it is so worth it.

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[Jgorm]

I did my rv with the West Maine stuff and is totally awesome. With a 7.3psd just inches com my knees it needed something. http://joegorm.com/soundproofing_the_cab_and_doghouse.htm

I did my old c3500 dually with dynamat and that also made a huge difference.
http://joegorm.com/stereo_and_dynamat_install.htm

Then I learned how too make my own dynamat for a fraction of that cost and I did my crown vic.
http://joegorm.com/2003_crown_vic.htm

I don't think mass absorption (dynamat) materials will do anything on a boat. If you don't hear reverberation when you hit it with metal, it won't do anything. If you do here it, it you hand nearby and see if you still hear it. If you do, mass absorption won't do anything to help.