Engine Compartment Ventilation older 340's-380's
 

I have been thinking of adding some extra air flow to the engine compartment. My 1998 and similar 380's and 340's dont have the new side ducts. I found the tear drop shaped ones that are used on the eliminator daytona 30' seem to fit very colse on the bulge on the gunnel.

I think the would have to be made a little thinner as to flex arround the bulge. Most of it is flat but the bottom edge needs to bend about 1/4" or so near the rear. I would also have the "point" end made with a slightly larger diameter to fit the contours better.

If I have this done I am curious if any one else would be interested in the same? Posibbly drive the cost down some.

Also what do you think of the design and Idea in general?

Ray,

Although I don't have my boat anymore, it seems like a bunch of work to do the job. When ever I wanted more air in Engine Compartment, I would just raise the hatch a little. Might be easier and less of a hassle. Just my 2 cents.

After all your hard work, you should be on the water and not working on additional modifications. Save those for the winter :)

Hope you season is turning out good now. I still might get a boat this summer, it is a Buyers Market for sure.

Mike

Hi Mike! All is going well this year, I decided to take the boat out over the 4th weekend to get some work done. Mainly issues with my wife - Too loud (mufflers) Potty dont work (Electric conversion). We were spending the weekend at my house watching fire works and stuff with the neighbors. I did remove and re-build the seawater pump. This is where the black gunk was comming from in the bilge, the front shaft seal was bad. I also put on drive temp indicators too. I should be back in the water on Friday or saturday.

I started thinking of scoops last fall but after seeing my Wife and kids use the sunpad I realized that would be a problem. I had to find out another solution. While I was running I did notice a reasonable amount of air pressure on the area where this bulge is. I figured It would be a good spot for a intake. Actually the installation should not take more than a couple hours and If I can get eddie marine to custom fabricate a couple of grills I think it would look good and be very functional.

Hope to see you out there soon, I was at Brennan Marine the other day and the have a nice 340 in stock....

Ray lookes like a clean set up, my old 29 Entiser had a vent in the same area but it was more square looken. The tear drop desighn you have lookes more stylish. Your rite ya definatly need more air back there.

Ray,
I have had a couple thoughts on the air issue. I need to crack my hatch and see if I have any speed changes (in the past it made no difference). Now I'm seeing that my flame arresters might be effecting air flow to the motors (check out the tech section) sooo if I change over to a different flame arrester will I not have enough air ?????????? (scratching my head). I have looked in the Rex Marine catalog and really liked the ones they make,some even have a built in cleat. They also offer them in many diff colors like purple:rolleyes:
The area you show would not be my first choice if I do this I would move it back to the same area they install the new ones at. The shape and style should look good back there. I have also seen them add on the straight (camper style) vents
:eek: Yuck!
Any thoughts? throw them my way:cool:
Look for your props I sent them today! Thanks again I now owe you one:D

Scott, Wich Rex marine vent are you looking at? A while ago I looked at their catalog and didn't see any that caught my eye. Are you seeing it online or do you have a catalog? I requested a printed catalog but they said 30 days +.

I also intended to pipe a duct back to the compartment from behind the vent. Kind of a ram air effect.

Ray,
I'm out of town but looking at the online picture I'm thinking those are the same. I like the idea of piping it to the back. I would try the hatch raising trick first to see if it really needs it.

The story from PQ goes like this (or so I was told) that one of there X testers named Ryan used to crack the hatch on tests and would see a change of up to but no more than 1 mph. When Ryan (nice guy by the way) and I were testing my boat he tried it and got nothing but a lot of noise;) he and I'm guessing others convinced the powers to be to change the mold to incorperate the vent. It might of helped the air flow???????? mabey the looks???
I would think that they would of used a airflow meter (easy to use) to confirm results before putting in a design change. Remember the wrong placement could actually cause less air to the desired location,venture (sp) type of effect. But my best guess would be that it's better to have it. One other thing to think about is water into the bilge or engine:eek:
So with all that said I'm ready to experiment by cracking the hatch again and looking for speed changes also I have a point and shoot thermometer that I can use to monitor temps.
One other thing they had told me was that a lot of air is pulled in through the side compartments and to keep them clear. Sorry no way on that one I store life-Jackets on one side and fenders and lines on the other. I rather cut in a vent than give up that space!
Sorry to ramble on just my morning wake up drinking coffee thoughts:D Scott

FWIW, I hear that EFI Engines are effected more by hot air than carb engines this is one more reason for the extra ventilation. I think it has something to do with the chilling effect carbs have on the intake higher up in the stream. whereas MPI do not benifit from this because of the close proximity of the injector to the port.

Ray do have have "relief vents" on each side of your stern? You can only get X CFM through your arrestors, anything more causes pressurization and most probably will slow you down. I think the PQ designers understand that. That would be for a stock application, yours my very well be different. I agree with the rest, crack your hatch an inch and see if you pick up any rpm's. Mine did zip! If you go ahead with the vents, billet or stainless is my 02.

I'm betting part of the new design is to allow heat to escape. After a run and shut-down you can feel the heat pouring up and out of those side vents. Never have had a vapor lock issue.

ps. your right aboout the efi motors and high temp/humidity. I can be down 2-4 mph when over 90/90.

Only shot I can find right now

Kentz, if you are talking about the round vents under the rear of the hatch yes I have 4 on one side and 3 on the other, they are about 3" in dia +-.

No, look at my picture, just above the tie-down eye. The plastic 2" vent with a flapper. There is one on each side.

Kentz. That is the scupper that from what I have seen drains water from an area in the gunnel that if had got water in it would just sit. I dont think it is for air but it might pass a little.

See this link: http://www.offshoreonly.com/forum/sh...threadid=26584

I could be wrong but I think it is for water drainage.

Ray is correct those are scupper drains. In my case with the Hydrohoist and the angle when deployed they become water intakes:eek:

Ray,
Please tell me thats not what I think it is in that picture on the vinyl.:eek: :eek:

Did you receive the props ok.

O.K. that makes sense!, but if the water level ever got that HIGH with the boat in the water wouldn't it swamp?, I mean you'd have the water level 1/2 way up the blocks.

If you were sitting level in the water and taking on water through the scuppers I'd grab a life jacket and call the coast guard because it would become a submarine in a few minutes.

Look at one of my past or should say the latest rebuild post and you will see a picture of the boat going down in the lift. That is what I'm talking about:)

Scott, Those picts were from when it was bought, That hole and acouple of others were repaired prior to me getting the boat. I will tell you this, If you look close you can see where the repair is. There is one on my seat that after a few runs it shows up like a quarter size hole that was repaired. I guess dirt adheres to the repair more than the vinyl. I will need some vinyl work soon. I figure I might as well use it and have the kids abuse it this year. Fix it right in a couple of years.

Update
 

I found some one that can make these vents for me, The will be polished stainless steel and cut with a water jet. I am waiting on a price for two but if anyone else needs a couple let me know and I may be able to get the price down. I will let you know when I get the price. Meanwhile I have attached a link for a PDF of the final design.

http://www.raymondbaldwin.com/vent.pdf

Got a price!
 

If you want any they will be $50.00 each. I will have my two in in a week or so I will let you know how they look. I was also thinking of having them powder coated too.

Ray - I assume you are comfortable that these will provide adequate air flow and not create some kind of turbulent effect?
If so, I would like to order a set for my '96 Vyper. Powdercoat might be nice. I'm down in St Joseph. Can send check to you or shop.

Thanks............Dave

The scuppers drain the water out of the collection box - which collects the water that backwashes in through the 3" vents under the sun lounge.

I would strongly suggest lifting your hatch before you cut your deck for vents. I tested many PQ's in my years working there and some boats would see an increase from better air where others wouldn't.

Another caution with putting a vent on the forward part of the deck gunwale where you are showing it, is that water will very easily enter your side storage/engine area from right there unless you plan to put a collection box / drain on the inside.

It's a whole lot easier to pop the hatch and see if it makes any difference before you start cutting.

Marc

Marc - you've been away awhile:( As you can tell we still need your expertise, visit more often:D

Kent

MK: I am trying to use common sense here, The newer 38's have a large air intake near the rear. Mine does not, I am simply trying to route some extra cooling air to the engine compartment. The idea is to force venilate it to keep it cool. I am not trying to gain speed but to keep my whippled engines from detonation because of high engine compartment temps.

I plan on using a neoprene 3" hose that is used for brake cooling on race cars. I also intend on putting a T inline with a drain hose to prevent water from accumulating. I can see a little water slpashig up there from a blown wave. But if a big wave hits there I think I have more problems going on than worring about a little water in the side storage compartments. ;) Anyhow the company that is doing the work for me seems real reasonable on pricing. The eddie marine aluminum vents were like $145.00 each. For there work I could design anything that would work.

bote loco: I am really not sure of the outcome yet but I believe they will at least force some extra air in the while at speed. Hold your hand ther while under way and feel the pressure. I will let you know how they fit once I get them in.

Kent - I read a lot but don't post a lot b/c I think PQ should be doing more posting to this type of technical stuff. I'll put in my .02 more often to try to help you guys out.

Raypanic - I would agree that if we're considering waves into that vent you will have much more to worry about than a little water in the storage. My statement was more aimed at rain water, washing the boat etc. We looked at numerous styles of vents while I was there, but never decided to add one b/c we always felt they looked "added on" rather than designed in. I have not seen the new vents up close, but I think if you can figure out a way to put a vent in that looks good - go for it! Maybe you could order a set of factory vents and install those? It can never hurt to have a little more air, whether for cooling the motors or for air intake.

Marc

Hey Mark good to still see you around. Will the new factory vents work with our boats I thought they were built into the molds?
That would be something I would consider if they were available.

Factory Vent
 

Glassed in, I wonder if it is part of the mold or added on, I know the covering wing is attatched later but what about the "Bowl"?

That is definitely in the mold and could not be added to your boat without some significant work, Scott.

Like I said, I have not seem them up close, but that looks like a very nice addition to the deck of the 38 (and I assume 34 as well)

Marc

Ray, I read you own a different boat now. But was curious if you came to any conclusions on your PQ ventilation issue after this last thread?

Dave