I thought I read earlier the throat was 3.75" ?

Fuk, I spent about 2 hrs early this morning looking for components for larger FA and for a fresh air / larger FA system based off 3.75" . 3.75" is brutal, but 3, 3.5", 4",so on and so forth not as tough.

Who is the OE manufacturer ? I tried finding that too, but came up empty.

Oh, yes...I found that. Didn't realize Barbron or there new owner (Wayne Wire) made them. Cool !

Yep, their office is in Kalkaska Michigan. having a PN will help them get going. I will keep looking for that.

You looking for the OE Mercruiser # of what you have ?

Maybe this is a stupid idea, but why not simply direct connect the TB with intercooler piping and run it up under the gunnels and place a normal FA there(K&N generic one)? All this stuff is rated for turbo pressures(backfire resistant) and by going from 3.5" to 4" right after the TB, you would/should not have a big restriction. This would avoid all issues with finding an arrestor to go on the engine.

I will be out this weeked and get a few more pics

I've had the pleasure of being boarded by coast guard several years ago. A group of us were all anchored together, there was a death on the bay the weekend prior, so they were making their presence known and just conducting routine safety checks. First thing they checked on my boat was the engine compartment and the flame arrestors to make sure that I had them and they weren't modified in an illegal way. Just throwing this tidbit of info out there, I know you are just swapping the stock ones for bigger ones but not just for your safety but also the safety of any crew onboard, please make sure any modifications are fully functional and not just thrown together to gain a few extra MPHs.

Kai definitely has my attention with this. Looking forward to see where this goes.

That is also what I was looking into, but wasted time on 3.75" to 4" connectors...which I finally found...lol.

Game on! I thought a lot about all the comments here and now have a direction.

Last night I was thinking of moving the FA...not going to do that as it could be a safety issue.
Heard about the idea that this could actually increase under hood temps by directing air only to intake. I agree.
Lots of investigation into parts and availability...for sure anything is possible.

So..what to do......?

For the time being, I have ordered the following.
http://vod.ebay.com/vod/FetchOrderDe...=1408146326010

I am going to pipe the air from the forward facing duct to the area of the FA like I mocked up with the flex tubing. I really believe that the way the inlet and outlet of the air on the sides of the boat are set up...especially with the bimini top shelves in place, that the air will travel into the engine compartment, some pulled to the intake of the engines and what is not needed, simply goes to the other vent on the side of the boat. There is NOTHING that helps get engine cool air, and the path of least resistance for air not needed for the engine intake, is simply the exit...it never has a chance to even pull heat out.
SO....my theory is that I will dump all the fresh air on top of the engines, let it use what it likes, and then the rest will have to travel across all the hot exhaust etc to get to the exit. In effect, the best situation is that all the air leaving the exit port is as hot as possible. Sounds simple, but why the air is directed the way it is must be to satisfy some rule or law. For sure, it is a safe and simple design, but it is not efficient at using the potential of the ONE AIR INLET per side. Imagine your window air conditioner working great....except you want air in your bedroom!! OOPS....they didn't think of that until viola.....central air!!!!

So...in a week I will have the parts, and then the saw comes out so I can cut the tubing and make it look all pretty. Hopefully, I can reinstall the bimini shelves with the 180 degree pipes, but if there is no room...oh well. My 17yo daughter said the boat looks like an "old man's boat" with the bimini on anyway. :)

Subtle ideas on the piping would be great. Like I said, the FA will be a separate issue, so that will come later.
My thought is to make some foam plugs for the sides when trailering, to makes sure bugs and birds don't enter.
Drill a few small holes in the lowest part of the piping to assure no water can accumulate.
Possibly add some large gauge wire mesh to the inlet side...once again to protect against debris entering.
Maybe do some kind of diffuser to get air directed around the FA...so the air does not just blast one small area.
And of course some super cool sticker to go on the side of the boat saying "RAM AIR INDUCTION", or "Danger-AIR INLET". Kidding on this of course...the stickers will go on the piping. :)

thoughts???




OK.. that's the plan.

From previous boats just like yours gaining speed with the larger Mallory arrestors, with no additional ducting, I'm gonna say your arrestors are priority #1, and then the air temps are priority #2.

Always deal with the biggest horsepower killer 1st for best value per dollar and usually effort.

I would love to jump aboard one of these 292's to see what would have to be done to add in a nice unrestrictive cold air system.

Link doesn't work.

http://m.ebay.com/itm/Universal-Blac...257Ciid%253A10

Does this work?

Not giving up on the FA, just need to find one that works. I want to get on with the project while I work with Wayne wire to get the FA made.

I will get that part number for the FA this weekend. No mods to the FA at all. It dropped right on the three studs that hold the original on. Like in my post the only thing is you have to lengthen the studs and add a spacer to clear the throttle cable. I have run mine this way for over a year with no issues.


Pics will be here saturday morning.

In case anyone cares...lol

Mercruiser 863416T (pictured first)

Mallory 9-31103 replaces above but no longer available...but it is...see next line
Sierra's parent company bought Mallory. Sierra's part # is 18-31103 and these are available
Pictured 2nd
2.05 element height / 7" Diameter / 3.7 " throat (mounting) / 2.9" overall Height

http://www.mercruiserparts.com/conte...3416T_550.jpeg

http://www.firstchoicemarine.com/ima...E-18-31103.jpg

To try to get my info straight, you have what I show below and they where made by Barbron ?

http://i.ebayimg.com/00/s/MTIwMFgxNj..._id=880000500F

This is a maybe.........

Photo just above (post #55) of the 'Unconstrictor' appears by looks to be just like Mercruiser #861443T


1st photo: The Unconstrictor sold on ebay. No longer available as the seller just had a certain quantity years back.
It's very possible the Unconstrictor decal is placed over the manufacturer and part # stamped in arrestor as this is an old repackaging trick. If someone has one, would you be willing to verify ?

2nd Photo : Mercruiser #861443T (notice it has stamped on top 'Barbron' and appears (try to read # on photo) to have Barbron Part #61443. These are availble thru Mercruiser for purchase.

3rd Photo: Mallory Marine says 9-31105 is a replacement for Merc #861443T. but no longer available..but it is..see next line
Sierra's parent company bought Mallory. Sierra's part # should be 18-31105 if they make/sell these but I can't find them yet.
2.05 element height / 7" Diameter / 3.95 " throat (mounting) / 2.975" overall Height

Again, the Mallory FA's are shown here : https://issuu.com/marinedirect/docs/mallory/224
And there dimension's are shown here: https://issuu.com/marinedirect/docs/mallory/224


http://i.ebayimg.com/00/s/MTIwMFgxNj..._id=880000500F

http://www.marineengine.com/parts/im...ry/861443T.jpg

http://cdn.crowleymarine.com/media/i...RY/9-31105.jpg

Similar but no center hole. It was the same name. It is the same design as the blue CP one.

Cool, thaks.

So like the FA's in post #54 ?

[ATTACH=CONFIG]557947[/ATTACH]

Digging through some pics I found this. It is made by Barbron

I use a Fluke temperature probe at work to measure process temps and after reading this thread I had to find out what temps I have under the hatch. Hot as hell day on lake Lanier yesterday with air temps in the mid 90's and surface temps over 100.

[ATTACH=CONFIG]558029[/ATTACH]

I placed the probe between both engines just to get an idea of bilge temps, next test would be to place it next to flame arrest or to see what in,et temps are.

[ATTACH=CONFIG]558030[/ATTACH]

The above pic was running at about 4000rpm and I had to look over my shoulder and take this pic while not killing myself. Bilge temps actually dropped as I increased speed so probably means I have good airflow to the engines.
Still made me think that a ram air would pick up performance.

[ATTACH=CONFIG]558031[/ATTACH]

The above pic was idling after a high speed run, temps gradually increased to 20+ degrees above ambient. Proves the bilge blower is most useful when idling. Also, I always crack the cover whenever I stop in the summer.
PM me if you need more info on the Fluke meter.
Pat

[ATTACH=CONFIG]558060[/ATTACH]

Here is a shot of the markings on top

Hope it helps

Any chance to get a better shot of the part number? I tried to blow it up, but could not read it. Thanks a lot.

a7390-2

Been reading through the thread, and thought I'd comment.

Just as you need to get good air in there, you need to get the bad air out. I've noticed with my 242 that there are intakes for getting "some" air into the bilge, but no extraction. On my buddy's Cigarette, the bilge is set up to ventilate quite well. The rear quarter on each side and the entire stern are open to the atmosphere. I believe that at speed there is a suction created at the stern that pulls air through the bilge. Our Formulas do not have this (my 242 doesn't). My other boats have had this set up (Four Winns and Chris Craft), but not this one. If I didn't think it would screw up the lines of the boat, I'd add vents just under the grab rails at the stern to help this along. I wonder how hard this will make getting my 454 into 5800-6K range rpm-wise?

Chasing out that tiny arrestor will definitely help in terms of air flow, but you still need fresh air.

I did the same experiment this past weekend with similar results. The port engine w/o the beauty cover pulled ~200 more RPM's during acceleration coming on plane. With both covers removed, the boat planed noticeably quicker. So the beauty covers are in the garage for the rest of the season and probably for good.

I see the posts about the larger flame arrestors, so I plan to order those once I sort out the correct part number and manufacturer.

This has been a great thread.

Dave.

I have a good opinion on why the use of beauty covers outside of the more obvious reason of 'creating a look.'

I've worked on many boats where water leaks right on top of them, because of engine hatch design. ie: where the hatches open. I would not want water dripping for hrs, days, or etc on top of my flame arrestor as water can/will enter the screen parts easy as it runs off top of arrestor. Furthermore, I would be positive Manufacturers don't want water dripping on and into a flame arrestor either.

Well, it is good to hear that the test would repeat! I really think that for the 292, the solution is to get a new arrestor(I sent a message to the company that made them to resurrect the design and make a few as I cannot find anything from Sierra, Barbron etc), lift the arrestor 4-5" from the current height with an extension pipe, build a kind of "hat" to help direct around the FA, and then duct air to the FA area. The "hat' would simply be a piece of aluminum that is larger by 2-3" in diameter than the diameter of the FA, with a shield around it....extending down and around the FA a few inches. This will help get ambient air to the FA...and not just blow by, and also help keep radiant heat from the intake area. Of course, it would not be too sealed up, so air can still move around a little. Imagine a large frypan upside down on top of the FA, with a cutout for the 4" air duct from the air inlet. With all of this, it could also be possible to put the beauty cover back on....maybe it could be integrated somehow too.
After all this...the engine intake will be as good as it can get without cutting fiberglass....which is not in the works.

Still all of this needs some work. The piping is easy.....and afternoon project. The "hat" is a little work for a fab shop. Finding a FA seems to be one of the biggest issues right now. I found a K&N one that could work, but really would like the Barbron version to make sure the safety functionality of the FA is not questioned. The K&N is not a direct bolt on.

Let me know if you find someone to make the FA as long as they fit properly and are CG compliant. I'll take two.

Dave

looks like I should start making FA kits!

I have an idea for an adapter that would make any carb FA work. I have to layout some material to see if it will work.

It would even offset the larger filter to clear the throttle linkage and offer a standard center stud mount to be used.

Do it - and I'll help sell'm, just got to give me decent wholesale pricing.

Well enough talk...I am moving forward. Turns out that the 496 air FA will fit right on the TB. This should flow more than enough, and it will clamp right on as it does on the 496. This will actually make things a lot easier for a number of reasons. The look will be different, but the function will be great.

So, I hope to get the new FAs before the weekend, and do some testing. It could even be the case that I can get the tubing done....so I will have most of it done.

Here is the FA I am putting on.

ARRESTOR-FLAME Mercruiser 862537T

Here is the latest from Revspan:

Here we go.* This is simply the parts put together without any idea if they fit.* From what I see, there are two option, one is the quick route to the FA, the other uses the 180 deg turn, which should wrap around the Bimini shelf and can move the pipe forward a little so the angle to the FA is a little better.* I like this idea as I would drill a few small holes in the 180 to assure water can drain.* Need to get it into the boat and decide what is best....but I think that a few cuts, some fab work to make some hangers and it should be good to go.
______________

Looks like some nice hardware Kai! Anxious to hear how the new flame arrestors work for you.

Cool !

Pics from a previous post.

If you can trim 'beauty cover' it may look Merc 565ish.

http://d29pb6nrvp2amd.cloudfront.net...cury565big.jpg