Although there is some debate about the need for fresh air in footboxes, and the best way to achieve it, I decided to put them in: I live in the mountains of the West and there will certainly be times when the temperature differential between the footboxes and outside air will make the vent system effective.
A search on footbox vents yields a number of threads showing member's systems but none (that I could find) provided a lot of specific detail as to what the builders did. So, my objective here is to provide as much detail as possible so that someone can replicate what I did if so desired or to use it as a starting point.
The key find was a 3" stainless steel tube with a damper flue from Dickenson Marine: DSC_5494.JPG
********** sells a damper valve housing similar to what Cobra Earl used but it is more expensive than I wanted to pay.
The photo below shows the damper flue inserted into the DS footbox. The retaining ring was made from an ABS 3" cleanout adaptor I found at Home Depot: DSC_5539 (1).jpg
Obviously I still need to complete the system to the roadster's nose as well as cut a hole in the elephant ears for the ducting to pass though. I think that the forward part will be more straightforward (I hope!).
I made an attachment for the damper-moving cable using a couple of sections of bicycle chain: The cable is a standard choke cable that I got from NAPA: DSC_5686.jpg
Excellent write-up, and great find with the Dickenson Marine flue damper. Just for fun you may want to insulate the left side Spectre pipes with Reflect-A-Gold tape.
Build School: July 14-16, 2017
Kit purchased: July 25, 2017
Kit delivered: September 13, 2017
First Start: December 22, 2018
Body painted and kit completed and drivable: July 2019 (but still not done)
CA SB100 Registration: January 2020
Mk4 - 289 USRRC Roadster kit, Roush 427SR with Schneider Racing custom camshaft, Fitech EFI, TKO600 (.64-5th gear), 15" wheels, stock brake calipers, under car exhaust with Spintech 7000 muffler, no roll bar, Russ Thompson turn signal, removable steering wheel, and many other small upgrades and modifications
The bicycle chain bit was used to solve the problem of the need for the place where the choke cable attaches to the damper valve arm to be able to rotate to allow the damper to fully open or close. I'm sure that there are other ways to do it but this seems to work: DSC_5686.jpg
There are two bicycle links. The one that is attached to the damper arm is fixed, i.e, it doesn't rotate as you can see by comparing the two photos. The upper link is free to move and the choke cable end is fixed on that link (it doesn't rotate about that link). So, when the cable is pulled, the upper link rotates relative to the lower one allowing the damper to open fully.
DSC_5692.jpg
Also, when the choke cable is pushed in, the rotation of the upper link allows the damper to fully close. It turned out that the link spacer (separating the two sides of one link) is exactly the thickness of the damper valve arm so that the damper valve end of the link that is attached to the damper valve arm can be fixed (not allowed to rotate) and the other end of that link, attached to the second link, can rotate.
I really didn't plan it out in this much detail-- I was just tinkering and it worked!
The bolt in the second photo with the black button head has the only purpose of covering up my drilling mistake.
The photo below shows the damper flue inserted into the DS footbox. The retaining ring was made from an ABS 3" cleanout adaptor I found at Home Depot: DSC_5539 (1).jpg
-Bruce
Very nice work. Your driver's side vent is located where mine is. I'm finding it blows up my left thigh. I'm going to play with some elbows to direct the flow better when I find some time. Good time for you to look into this while access is easy.
-Steve
Thanks Steve. I'm glad that you brought this up. I'm impressed by the amount of air the Atwood 3000 pushes and was wondering if it might be a problem if not directed. After your post I looked around and found this louver from Vintage Air: https://www.summitracing.com/parts/vta-490535/overview/
It's about the right diameter. It's not too expensive so I may just get one and try it out.
I'll also look around for an elbow to get it directed more to my feet.
-Bruce
I had the plastic blast gates that are commonly used and hated them. They always felt cheap when you operated them and then they started to stick. I changed over to something similar to what you did. I used exhaust cutouts. I took the motors off and put a bellcrank from a model airplane on the shaft for the cable to attach to. I lined the butterfly with cork gasket material to seal and not rattle. Works great. Nice and smooth. I used a flanged exhaust "reducer" (even though is was 3" to 3") and it bolted straight up.
Now if someone comes up with quiet fans, I want to hear about it.
Very nice work. Your driver's side vent is located where mine is. I'm finding it blows up my left thigh. I'm going to play with some elbows to direct the flow better when I find some time. Good time for you to look into this while access is easy.
-Steve
On the advice of someone before me, I put in an elbow in the driver's side footbox (half of one anyway, trimmed it some to clear the clutch pedal). Seems to do the trick nicely. It's an ABS elbow from Home Depot.
On another note, as for the butterflies (again from someone before me) I rarely close them, if ever. They stay open pretty much 100% of the time. So I wired the push-pull knob so that when pushed, it's open, and when pulled, it's closed. That way the knob is pushed in and out of the way. Again, works pretty good for me.
If Brute Force doesn't work, you're not using enough of it. Basic Stuff: MK4 Complete Kit #8439, Wilwood's, 17" Halibrands. Extra Stuff: Stainless brake and fuel lines, Breeze cooling, Battery mount, SS Roll Bar. Old Fart Stuff: Heater, Seat Heaters, Footbox Fresh Air, Stereo, Keyless ignition, Power Steering, Hyd Clutch. Young & Dumb Stuff: 427w Dart, TKO600, 3 link Moser M9/Ford 9", 3.5:1, Eaton TruTrac Posi. Graduation Thread
Curious. Has anyone thought about making a "box" that would surround part of the header to draw heat off the header instead of using the in dash heater. Waiting for my kit to show up in about a month and was just curious. That would put the blowers under the hood instead of in the dash to lower the sound a bit. Am I even making any sense to anyone?
Curious. Has anyone thought about making a "box" that would surround part of the header to draw heat off the header instead of using the in dash heater. Waiting for my kit to show up in about a month and was just curious. That would put the blowers under the hood instead of in the dash to lower the sound a bit. Am I even making any sense to anyone?
Some small single engine piston airplanes do this for heat. A metal box or tube installed around an exhaust stack has air fed into it that would then be routed into the cabin. A simple push/pull cable would open/close a butterfly to control on/off. They used the same thing for carb heat to prevent venturi icing.
We dont have the ram air that even a baby Cessna does, so a small fan in the engine compartment would work... interesting idea.
Curious. Has anyone thought about making a "box" that would surround part of the header to draw heat off the header instead of using the in dash heater. Waiting for my kit to show up in about a month and was just curious. That would put the blowers under the hood instead of in the dash to lower the sound a bit. Am I even making any sense to anyone?
Kind of like a Model T manifold heater. The danger is an exhaust leak COULD allow carbon monoxide to enter the passenger compartment. A fresh air intake is essential. You could duct from the small brake duct openings in the nose.
I like the idea of the exhaust cut of valves that Avalanche suggested as they look more air tight than the duct damper valve. Also like the idea of having a hidden switch to electronically open and close them.
Every V-Dub Beetle ever made used the "box around the exhaust" for passenger compartment heat. The engine cooling fan flow was diverted into the box and blew (somewhat) warm air into the cabin.
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I am going to try this for my fresh air solution to the foot boxes. This also provided fresh air to my heater blower. I flipped the blower part of the heater upside down so the intake is to the outside (there is room for the wiper motor). I connected a 3" adapter to the blower and attached a 3" brake-duct vent, which I will route to the front. I will be installing the butterfly valve...thanks for the Dickenson Marine option.
I did not like the way the blower connected to the heater box with self-tappinig screws into plastic so I cut a couple of aluminum strips, drilled, and tapped the strips then glued them to the inside of the heater box. Now the blower and heater box are bolted together with 10x24 cap-head bolts.
I am going to try this for my fresh air solution to the foot boxes. This also provided fresh air to my heater blower. I flipped the blower part of the heater upside down so the intake is to the outside (there is room for the wiper motor). I connected a 3" adapter to the blower and attached a 3" brake-duct vent, which I will route to the front. I will be installing the butterfly valve...thanks for the Dickenson Marine option.
I did not like the way the blower connected to the heater box with self-tappinig screws into plastic so I cut a couple of aluminum strips, drilled, and tapped the strips then glued them to the inside of the heater box. Now the blower and heater box are bolted together with 10x24 cap-head bolts.
I'm not sure if my heater blower is the same as yours, but the intake for the squirrel cage/fan is on each side of the fan. In my case I made a shroud to go around the blower fan (in addition to ditching the sheet metal screws as well). So you may have to block off the other side of your blower, but that may hinder the air intake/air flow as well. Here's my setup https://thefactoryfiveforum.com/show...g-modification
If Brute Force doesn't work, you're not using enough of it. Basic Stuff: MK4 Complete Kit #8439, Wilwood's, 17" Halibrands. Extra Stuff: Stainless brake and fuel lines, Breeze cooling, Battery mount, SS Roll Bar. Old Fart Stuff: Heater, Seat Heaters, Footbox Fresh Air, Stereo, Keyless ignition, Power Steering, Hyd Clutch. Young & Dumb Stuff: 427w Dart, TKO600, 3 link Moser M9/Ford 9", 3.5:1, Eaton TruTrac Posi. Graduation Thread
Zots: This is an interesting idea for getting fresh air into the footbox. By the way, the damper in the Dickenson Marine product doesn't completely close off the tube so I glued a disc of rubber of the appropriate diameter to the valve to make it more air tight.
-Bruce
I'm not sure if my heater blower is the same as yours, but the intake for the squirrel cage/fan is on each side of the fan. In my case I made a shroud to go around the blower fan (in addition to ditching the sheet metal screws as well). So you may have to block off the other side of your blower, but that may hinder the air intake/air flow as well. Here's my setup https://thefactoryfiveforum.com/show...g-modification
Exactly what I was going to say. The fan also pulls air from the motor side.
BTW, the Dickenson Marine flue dampers (https://www.amazon.com/Dickinson-Mar...SIN=B007PS2BX4) are only $130 for the pair. But then you have to buy cable pulls (which most likely won't have the cool period-correct knob).
And don't get me started on the "customer service" from Finish Line...
BTW, the Dickenson Marine flue dampers (https://www.amazon.com/Dickinson-Mar...SIN=B007PS2BX4) are only $130 for the pair. But then you have to buy cable pulls (which most likely won't have the cool period-correct knob).
John
ah, makes sense... are the blowers really needed? I guess if you're sitting in traffic you'll get no airflow, but at speed - if plumbed into the mesh ducts at the nose of the car, you should get nice airflow
Necessary? No. Plenty of guys have the vents without the blowers, and I'm sure you'll get plenty of opinions either way. But at $40 it's an easy add at build time. It would be much less fun to run the wiring for power on a completed car.
FWIW. I skipped the dampers all together. Have the booster fans to move air when riding slow or stopped for any longtime. Have found that not having the dampers was not an issue as I don't drive the car much below 40 degrees due to the tires.
One of the rare occasions for a cold weather run was after the FvF movie last Sunday. We did a 3:15 showing & I came home in the dark. Temp dropped quickly without the Southern sun shining down, was in the low 50's during sunlight.
I run with a tonneau cover when I expect it to be cold & with a sweatshirt, B2 jacket, nomex track gloves & baseball hat never even turned on the heater fan. Most of the 35 minute trip was on I-520 at 80MPH. Only wished I had my flight hat to keep the back of my neck warm temp since it dropped to the low 40's.
John added the last part when I saw your post. Don't think the just the tubes without the booster fans move much air. Used to put plugs over the vents for the winter & no longer bother. Maybe up North dampers would be necessary with a closed car driven in the winter but not in NC. Don't even know anyone who has a roof. I am the only one with a Tonneau cover & we meet every month year round for our C&C.
Last edited by BEAR-AvHistory; 11-28-2019 at 01:40 PM.
Kevin
MKIV #8234
Coyote '14/TKO-600/3-Link 3:55 Rear I love the smell of 100 octane in the morning.
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Delivered 2/7/14 - Plate "COYOTE NC1965" 3/25/15
I used plastic blast gates, 'cuz that's what Cobra Earl provided in the kits he used to sell. They work OK, and take a bit of thought & effort to get operating; they have never been what I call smooth. Also, to fit the blast gate at the front of the foot box, you have to trim the gate pretty aggressively. The damper solution appears to be a smoother operating solution and appears to avoid the modification (but I haven't ever used or seen one, so I don't know for sure).
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Originally Posted by BDHoneyman
