Mathius

Ok, I know most of the mods you guys do to these cars have more to do with performance and speed, rather than comfort, but I'm interested in learning how the stock dash vents, a/c, heater system works, and how you could relocate and/or add vents to the system.

I'm particularly interested in knowing how the vents open and close, and how the switch works to activate whatever it is that opens or closes the vents.

I don't have a particular project in mind, but I've thought in the past of adding vents to the rear of the car to aid in heating the car quicker. I've also wondered about the posibility of using different vents and/or relocating them if I were to build a custom dash.

Fabricating the ventilation system wouldn't be too difficult I don't think, aluminum tubing could be used I think, but as stated, I'm not really certain how the vents are opened and closed, and how the switches work as they seem to be mechanical and not electrical.

Also, maybe there's a better or at least a different way than stock that might accompilsh the same task?

Mathius

bnoon

Since most of these cars ar so well worn by now, the first couple of things you can do to get your car warmer/quicker is to first make sure everything is in proper working order.

Many times the heater core can become clogged. Clean/replace as needed.

The foam seals in the ducting are almost certainly rotten if it's been a daily driver all of it's life. You can get new stick on foam at most auto parts stores.

Also, if your car is not so equipped, get a heater core bypass valve installed. Many thirdgens have them, but many don't (mine doesn't). When you first start the car, leave the heater turned off for the first few minutes until it starts to warm up on the temp needle. The bypass valve helps the car warm up a bit quicker by not allowing water to flow through the heater core (small radiator) when the heater is not turned on (vacum operated). Every little bit helps.

Also, if you're running a cooler temp thermostat, it will help to switch back to a hotter one for winter. I have to do this in my car, otherwise it never sees the high side of 160 in the cold winter months and the fan never runs, even in traffic. I'm going to go back to the 200* stat this weekend.

Mathius

Bnoon,

All very very good information thank you, but not really what I was looking for. My current car (92 six banger) is looking like it's going to become a parts car any day now, so your suggestions aren't really relevant for me. As I said, I don't have a specific project in mind. I really want to learn more about how the ventilation system works, and how I could make minor changes to the system like updating my HVAC controls, or moving vents around.

Mathius

JeremyNYR

iTrader: (2)

I'm not trying to avoid the question, but the best way to learn how it technically works is to look through a service manual and possibly take apart the dash and check it out for yourself. I have a service manual for my 84 TA and I'm pretty sure it has a breakdown of the HVAC system with diagrams and all that. I also got a good idea of how it functioned when I stripped down the body to sheetmetal.

onebinky

iTrader: (1)

The control head is basically a vacuum controller and a cable controller.

The vacuum controller applies manifold vacuum to the blenddoors at the ducts, which then open or close and direct the airflow to where it needs to go. The blenddoors are basically just vacuum actuators and little flaps.

example: You select def/floor on the controller. It will open the blenddoors for the floor vents and the defroster duct.

The cable controls one larger door that will allow only a certain amount of air to pass thru the heater core and into the cabin.

example: You set temp to 3/4 hot. The door will direct 3/4 of the airflow thru the heater core, and 1/4 will be fresh air from outside the vehicle.

You also have a blenddoor for max A/C which will only allow recirculation of cabin air, and not allow any outside air in.

Like Jeremy said though, most shop manuals will have a routing of all the ducts and vacuum lines.

Rage13

i'm going to start working on the a/c and air passages for a custom dash near the end of this winter. i was thinking the best way to go about the air passages would be to make them out of fiberglass. its would be light and you could mold it into just about any shape you'd need. also planing on using servo motors to move the doors instead of vac.

onebinky

iTrader: (1)

Hope you plan on doing it outside of the car and allowing it plenty of time to cure, the smell of that stuff permiates everything and doesn't go away for a while

If you could form a mold out of foam and do it outside though, It would probably work out pretty good.

Rage13

thats the idea

911rsq

Mathius

if you want vents in the rear of the car, look down by your right knee when you are sitting in the car. those vents are connected to the heater system just behind the radio. if you have ever taken the top of your console out, it is pretty straight forward. behind where the radio sits is where the in dash vents connect to the vents in your console. disonnect it there and fab up some small tubing and route it thru your console back to where the rear ash tray is on the back side of the console. take out the ash tray and find you a vent from another car that will fit in its place and you are set. this rear vent will work when you have the heater on....but dont forget, your knees are gonna get cold now!!!