manila3

Hi,
May I know if the 1987 3.2 carrera has fresh air going inside the cabin all the time through the front vents? I am comparing it to cars with a switch that can control the recirculation of air in the cabin. The fumes in front of me always goes inside the car.
Thanks

theiceman

I have a 78 SC ( no AC ) and the front dash vents are fresh air only. Ian has a great pictorial for this on the Carrera.

I hope Ian doesn't mind .. here is the link to his site , your answer is in there .. it is a really good site.


http://members.rennlist.com/imcarthur/

AJ88CAB

The top two levers on the dash control the fresh air amount (left lever) and fan speed (right lever). With both of these levers pushed to the left, the fresh air is as "off" as it can be. In reality it is not an "air-tight" seal and the forward motion of the car will force some air (and fumes) into the car. Also, there is no activated charcoal filter like in some newer cars. So, stopping the fume odor entirely is probably not possible.

RL911

air really only blows into my 86 front vents when I have the ac or heat on. Not much fresh air flow otherwise, except to windshield and floor only, just a trickle out the others.

ron mcatee

If the front air box assembly (plenum) in the trunk doesn't have the cables adjusted properly, you will get ambient air in the car, regardless of the lever position. You need to push the levers to the far left and check to make sure the flapper valves in the front air box are closing all the way. Until they do, you will get ambient air in the cabin. You'll have to remove the cover and hoses to expose the flappers.

rusnak

I'm pretty sure there is a some passive air circulation. No, not enough to blow in your face, but there is some circulation due to air pressure generated by the scoop facing forward and the extraction vents facing backward at the top of the rear window.

manila3

Thank you all for your posts. Its a fantastic car but with just a different orientation to me.

imcarthur

Blue is Fresh Air
Red is Heated Air
AC not shown for simplicity.

The heated air system is drawn from the rear.

The fresh air ventilation system is drawn from the hood grill.

Ian

rusnak

Wow!! I have to "right click, save as" again. Two of my computers are on the fritz, dangit.

The owner's manual calls it a "flow through" fresh air system that does not produce a draft.

manila3

Thanks Ian. Great site by the way c/o theiceman.

manila3

What about the rear part? do we need to check the heat control valve? does it affect the cold air in anyway even with the a/c on? Thanks

imcarthur

No. There are 3 separate systems in the 911.

Hot air from heat exchangers in the rear.
Fresh air via front vents.
AC from the front (with the cooling system sprinkled front & rear)

The only time they intersect is in the ducting in the dash.

Ian

RL911

Yep, that's how mine works...no fresh air from the vents along the middle of the dash, only from windshield and floor vents, heat and ac air flow as noted in pic...whew, I'm not crazy and my hvac controls work fine.