James Cowl downdraft carb box install

rockwoodrv9 · #1 11-19-2016, 02:04 PM

I am trying to get my carb box installed on my James cowl. I am stumped. My only other idea is to go to a muffler shop and have them fabricate a bend to make it work or try glassing something up. Glassing may be easier in the long run.
Here are a couple pictures showing the issue. The front of the air filter is at the height where it needs to be to meet the front of the cowl. If you have pictures or ideas, I would sure love to know what you did to solve this. I know I am not the first person to have the James cowl and this exhaust system. Thanks for the help.
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This one is just a shot of my panel lit up!
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Radomir · #2 11-19-2016, 04:54 PM

See example:

rockwoodrv9 · #3 11-19-2016, 05:51 PM

Thanks for the response. I had that photo and I don't believe that is the same exhaust box I have.

I can use SCAT tube to make the bend, but still working on a fix for the carb heat intake. I may have to cut it off the box and move it to the front to allow me to connect it to the air filter tube.

It is always interesting trying to complete a build!

DanH · #4 11-19-2016, 08:28 PM

Rock, look up the big filter updraft air box Chris Zvatson did on his Lancair.

rockwoodrv9 · #5 11-19-2016, 09:28 PM

Dan,
I looked up Chris's work. Impressive for sure. I have a great plenum and baffle system I am finishing up now.

With the James cowl, it restricts the air filter to the KN Will supplied with the cowl. Well, I could do major modifications and open up the intake to a larger or even square shape, but that is more than I want to do now.

After speaking with Will and looking at it a bit more, I believe the best option is to use a piece of scat from the carb intake box to the air filter tube. Cut the carb heat fitting from the exhaust muff box, seal the hole, and move it to the front facing surface on the muff. That will allow me to run the SCAT tube and a shut off between the alternator and starter. When I get back to the airport Monday, I will see if that will work.

I had to re-clock the air intake on the muff that goes to the left side cowl inlet to fit around the fuel line. That went pretty well so I hope re-locating the heat outlet will work as well too.

I can't be the first to use a downdraft carb with a James cowl, so not sure why I am having trouble making it work. I have found when it is not going as it should, I am usually the one making the error. I am not sure what it is this time.

Kyle Boatright · #6 11-19-2016, 09:53 PM

Quote:

Originally Posted by DanH

Rock, look up the big filter updraft air box Chris Zvatson did on his Lancair.

Here it is:

http://www.n91cz.net/airbox/airbox.htm

crabandy · #7 11-19-2016, 11:36 PM

rockwood,
It looks like you are trying to fit separate systems together with a "one piece fits it all together" solution. Most likely anything cobbled together from unmatching parts won't meet your standard.
The only way I know for you to gracefully do this is to Make something yourself to fit the front (cowling) and the aft (carb) to fit an air filter and any other required components.
It's worth $10 in foam and a nice 6 pack to cobble something together in a couple nights and see what if????? Odds are you'll scrap the first model but the small investment will steer you onto the path to completion.
Happy building!

DanH · #8 11-19-2016, 11:44 PM

Quote:

Originally Posted by rockwoodrv9

Dan, I looked up Chris's work. Impressive for sure. I have a great plenum and baffle system I am finishing up now.

I'm not talking about a cooling plenum. Follow the link Kyle posted for you. The large flat filter has far more media area than the little cone filter you're trying to use. Free power.

N941WR · #9 11-20-2016, 08:51 AM

I have never liked how the transition from horizontal to vertical looks so when I installed mine, I modified the FAB.

Here is a picture of my solution.

Notice how the FAB now angles upward towards the cowl opening and that I had to make a custom flapper for the carb heat.

It seems to work very well.

Rupester · #10 11-20-2016, 09:38 AM

My alt air heater is much smaller than yours, but still required something to link the filter housing to the intake snout. I used a short (3" to 4") piece of scat tube with clamps to do it. Mine is similar, though not identical, to Radomir's pic. I'd post a picture, but I'm not presently at home where I have access to the photos.