MGExp

MGA Forum

Footwell Ventilation System

Moss Motors
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor

MGARuss Avatar
MGARuss Silver Member Russ Sharples
New Jersey, USA   USA
1960 MG MGA 1600 "Bonnie"
1993 Mazda MX-5 "Bombita"
The worst aspect of driving my MGA in the summer months is dealing with the heat in the footwells. I have measured temps of 110dF down there on days when it is 90dF outside. I'm not sure if running the heater fan helps. The air coming out of the heater (set to cold) on a really hot day is pretty warm. I don't think my heater valve is leaking as per Barney's suggested test of comparing the temp of the hose from the valve to the heater vs. the top radiator hose while the engine is warming up - the heater hose does not get hot. My theory is that on a 90 degree day it is hot enough in the engine compartment that just routing the air from the grill through the hoses and heater box will warm it up considerably. I plan to test this theory someday but a recent drive back from a car show convinced me I had to do something now. So this is what I did:









This is made of an oil funnel, two shopvac elbows (one was an actual elbow, the other is a brush that I removed the bristles from), and a length of shopvac hose. The essential part is the wooden bracket - it holds it all in place at the right height and not touching the body. It is secured everywhere by velcro straps so it is trivial to remove. The hose is routed behind the heater box and comes out just above the accelerator pedal:



The hose and intake don't interfere with the passenger's legs and don't interfere with the door.

On the drive to the Hellertown show it worked well, the footwell never got hot, though it was just a mid-eighties day. I still have to try it on a mid-nineties day.

I think the two elbows probably slow the airflow down a bit. A smooth bend in the hose might work better but the elbows are essential for support. So I need to figure out a better support bracket. I'm thinking of a larger piece of wood that has a slot to grab the windshield frame and then a slot to grab the handle. If I can get more airflow, I might create some outlets for the passenger as well (though there usually isn't a passenger so that could be a waste. Having a fan in the rig could be good too. Finally, I've wondered if it would be possible to put an ice chest in the passenger footwell, fill it with ice, and blow the air through that. They use these kinds of coolers to cool the cockpits of small airplanes before takeoff.

Russ

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
Aridgerunner Avatar
Aridgerunner Silver Member Bill Bussler
Montoursville, PA, USA   USA
1956 MG MGA 1500 "The A"
1959 Triumph TR3A "The Mistress"
Cool idea. Pun intended. Did the judges take off points for that?smiling smiley

Tbird Avatar
Tbird Eric Taylor
Land O Sky, NC, USA   USA
If it were a coupe you could use the Thermador Car cooler (popular just before the far out concept of auto A/C became a reality).




Guess you could call yours the "Sharples Happy Feet"

Better get a patent on it - somebody will copy it and make a fortune!

thumbs upthumbs up

Eric

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
Gary E Avatar
Gary E Silver Member Gary Edwards
Kernersville, ,N.C., USA   USA
Another method.



Gary


Attachments:
IMG_1800.JPG    46.8 KB
IMG_1800.JPG

Jeff in Iowa Avatar
Jeff in Iowa Jeffrey J
Iowa City, Iowa, USA   USA
1970 MG MGB
Hope you don't suck up a bee!

58twincam Avatar
58twincam Charlie K
Allentown, USA   USA
Hi Russ, pretty cool idea. Do you think that you can rig a fan up in the tube like the NASCAR guys do with their brake duct cooling hoses?
When I saw it Sunday at the show I thought that Lucas just introduced their new "adaptive cruise control" and the air tube was some sort of wave guide antenna for the cruise control system! LOL
My ride to the show wasn't that bad either. I could actually feel a slight draft of cooler air from the heater vent. I am happy with the results of my insulation project.


Attachments:
image.jpg    65.5 KB
image.jpg

mgageoff Avatar
mgageoff Geoff Howard
Ashburn, VA, USA   USA
Well, this is interesting. The whole reason I'm planning on replacing my heater valve (current thread happening asking for advice) is because the air coming out of the footwell air supply with the valve shut off and properly adjusted for "full off" according to Barney's instructions is still hot. While the valve is not leaking, I've assumed the heat means that my valve is passing at least some coolant when shut off and is therefore "leaking" internally". If you and others are observing that the air through the heater box is always hot no matter what (very different from what some people including Barney seem to experience) now I'm questioning what is really the issue. Maybe I'll rig up a few spot temperature monitors in the fresh air supply hose and the output after the heater to see what I can figure out in addition to trying to measure the temp of the input/output hoses as you did. How did you measure the hose temps?

I've also flirted with making a poor man's AC with a cheap cooler and ice with antifreeze circulating through a makeshift heat exchanger. Some people call that a swamp cooler, but that is really an evaporative cooler setup.



Geoff Howard
http://mgaexperiment.blogspot.com
Now Playing on the Blog (8/8/2013): Don't Blow Your Top

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
MGARuss Avatar
MGARuss Silver Member Russ Sharples
New Jersey, USA   USA
1960 MG MGA 1600 "Bonnie"
1993 Mazda MX-5 "Bombita"
Geoff,

My temperature experiment was to use these three thermometers and put one probe in the grill, one just before the heater (at the flap) and one in the heater outlet in the footwell and then drive the car hard. My hypothesis is that it is heat in the engine compartment that makes the air hot, not circulating water. So, my expected result is that for the first 20 min or so, while the water is up to 180dF, the air will be the same temp on all three because the hot water is not the source of the heat. Then I get out on the highway and drive 65~70 for a while and get the engine compartment hot and I think I will see the latter two temp readings rise but the first will stay lower. Regardless of the result, I will also run the test with the heater bypassed (hoses connected together).

If my hypothesis is right, there's not much to be done to improve the temp of the ventilation air meaning a new source of air, not coming through the engine compartment, is needed. I don't think it is practical to insulate the hoses.

Have you tried Barney's test to see if water is circulating through the heater core - e.g. feeling the heater hoses to see if they get warm as the engine warms up?

Russ


Attachments:
IMG_7575.jpg    35.1 KB
IMG_7575.jpg

Tbird Avatar
Tbird Eric Taylor
Land O Sky, NC, USA   USA
I wonder if with only one shut off valve on the system - the water in the heater core will become hot partially due to natural circulation. I would think that the flow near the waterpump at the water branch pipe would only aid the natural circulation. I'm talking about fluid flow inside the same pipe because of different fluid temps top to bottom (with the control valve shut off). Same thing happens on my '60 Tbird and 2012 truck - the heater core gets hot even with the valve shut off.

Russ - your bypass method will tell the story on that theory. Good point also that a very poorly insulated metal heater box will only aid in heat transfer.

Eric

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
mgageoff Avatar
mgageoff Geoff Howard
Ashburn, VA, USA   USA
OK, I see your over-engineering and raise you one. I've just ordered a 5 pack of waterproof temp sensors for $8 (incl. shipping: http://www.ebay.com/itm/301659541715?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT) and will wire them up to an Arduino micro processor (have several on hand) to capture data at 30s or 1min intervals as I drive and will graph it all. I'll measure the three positions you mention, and then just because I'll have two more I'll measure just outside the heater box and maybe somewhere else in the cockpit - up by the speaker grille or something, or maybe just to the side of the windscreen where you have your funnel set up.

The parts arrive next week, and I'll have off recovering from surgery. Hopefully I'll be feeling well enough to solder but not well enough to work...



Geoff Howard
http://mgaexperiment.blogspot.com
Now Playing on the Blog (8/8/2013): Don't Blow Your Top

MGARuss Avatar
MGARuss Silver Member Russ Sharples
New Jersey, USA   USA
1960 MG MGA 1600 "Bonnie"
1993 Mazda MX-5 "Bombita"
Oh sheesh - an arduino? You sound like my 23 year old son. Ok, you got me on the technology front. What is the arduino going to do? Measure a varying resistance from each sensor and then write it out to some storage? I was going to use a camera to record the temp readouts during the drive. Low tech but within my skill set. Maybe I need to upgrade my skills and learn this tech. Ok, so let's see who gets results first!

mgageoff Avatar
mgageoff Geoff Howard
Ashburn, VA, USA   USA
The arduino acts like a small cheap computer. A little program on it will sample the temp from each of the 5 sensors and then probably dump it out to my laptop riding shotgun. Sounds harder than it is, but still harder than taking pictures. It will be safer (unless you put a co pilot on the camera) and I'll get a lot more data and a pretty graph. Your approach is more sensible but those sensors looked expensive and I thought it would be good to get info from two different cars. You will finish first no doubt!



Geoff Howard
http://mgaexperiment.blogspot.com
Now Playing on the Blog (8/8/2013): Don't Blow Your Top

MGARuss Avatar
MGARuss Silver Member Russ Sharples
New Jersey, USA   USA
1960 MG MGA 1600 "Bonnie"
1993 Mazda MX-5 "Bombita"
Geoff,

I'd be interested to see one probe taped to a carb float bowl and another located in the transmission tunnel. Maybe I'll do that test too later. The working theory is that all of the heat in the engine compartment exhausts through the tunnel. Also, I'd video the whole test so you can easily correlate the temp readings with what the car is doing. I plan to video it using a camera mounted on a suction cup mount so I don't have to hold it.

Russ

DavidMGA1600 Avatar
DavidMGA1600 Silver Member David Lake
Gold Coast, Queensland, Australia   AUS
1960 MG MGA "Dads Car"
1961 CycleKart Race Car "Team Ferrari"
Geoff,

I like the idea of your test.
Be very interesting to see the heat more through the car as the heat is generated.
cannot wait to see the graph and the debate begin.

Next test is to test air pressures in the engine bay. Is there a cheap probe to record this.

Russ,
I like your setup. Fresh air from outside has gotta be better than drawing through a tube via the engine bay.



David

1960 MGA 1600 Convertible,
Gold Coast, Australia.
The 5,791 Day Restoration

The CycleKart Club - Forums and more for builders & racers of home-built 200cc vintage-styled karts.

Stevieg Avatar
Stevieg Steve Gyles
Church Crookham, Fleet, Hampshire, UK   GBR
1958 MG MGA
I fitted an Attwood 3" Bilge pump in the trunking to the heater box. It displaces 4 cu m air per minute. It certainly increases the throughput of outside air significantly.

Steve


Attachments:
Bilge pump.jpg    20 KB
Bilge pump.jpg

. Hide banner ads & support this website by becoming a > Gold Supporting Member <

To add your reply, or post your own questions

Members Sign In   or   Create an Account

Registration is FREE and takes less than a minute!


Having trouble posting or changing forum settings?
Read the Forum Help (FAQ) or contact the webmaster