slicky rick

This is also something i wondered why porsche did not have on the 997's, interior recirculation filter. Bmws, mercedes, toyotas, the whole lot of cars had it since as far as 1996 if i recall right. Purpose of course is easier maintenace and it protects evap from getting dirty from recirculated air. My 09 mitsubishi did not have the filter but there was a retrofit item available if owner wants to install one. Anyone knows if its possible for our 997.2 ac's. The 991's already have it.

StormRune

I think you are way too over-concerned about this one. If your interior has that much stuff flying around in the air you have bigger problems.

You don't normally want to use recirculation anyway since it drys out the air too much... bad for your sinuses, nose, etc. Only in the very hottest climates is it really useful and even then for a limited time.

slicky rick

hi storm. firstly i am not from the US where the air is dry. in addition, my car is almost always on recirculation because having it on vent mode allows very hot air to get into system, im in a hot tropical country my friend, where the air is humid and hot. not to mention dusty

slicky rick

and i have to admit, a bit polluted. i think you can imagine how it would be following a smoke belching public bus with your vent open...i guess you get the drift. my car is a daily driver. stuff flying around stays outside if you keep the vent closed.

wwest

First, the only period of time, climate wise, that "recirculate" can be used safely, or should be used at all, is during hot/warm periods that "require" A/C use. That should also mean windows and doors tightly closed, no source for incoming airflow other than the "Fresh", filtered, airflow path.

wwest

In extreme conditions, HOT climates, you could easily run the system in maximum cooling mode. The reheat/remix door/vane will be fully closed, no system airflow through the heater core.

That might well result in airflow that is so cold as to be discomforting, and possibly an "Ice Box" cabin atmosphere. To prevent both effects I use the blower motor speed adjustment to control the level of COLD airflow entering the cabin, plus allowing airflow only from the footwell ducts.

A side benefit is a slight FE improvement due to lower compressor cycling periods. Plus in HOT climates a lower heat load on the engine coolant radiators.

wwest

Some folks have complained of the discomfort from radiant heating of the console area due to the still HOT heater core just inside. You can abate this issue via a manually operated water flow shutoff valve in the coolant line to the heater core. Close it throughout the A/C use period, open only for COLD climate periods.

slicky rick

Hi west, i agree with the idea of the manual valve with the heater core, used to do that with my old ac systems.
In tropical countries, the ac is almost always on when you use the car. In less than clean air areas, the ventilation is almost always in recirculation. I do not understand your ice box explain, but our porsches have a climate control system where it regulates the temp. All we need to do is set the temp and oulets.
Nevertheless, in the interest of this topic, the question is is there an easy way to retrofit a internal recirculated air pollen filter. I hope our brothers who read this post would contrivute their ideas on how this could be done rather than stating why it should not be done.
As an additional note, if this should not be done, why is it, the porshce 991, now included, that the recirculated air filter is now a standard feature in almost all cars! If recirculated air should not be regularly used, why did all these manufacturers now decide it should be standard on all their cars and trucks and....
For me, when car manufacturers start making something a standard item on a car, it means there is a huge benefit to it, usually.

Chaos

Beano or Gas X should help!