OJ GTS

Hi all,

Is there something wrong with my car, or does the lower centre vent seems to have very little flow reaching it, meaning that it's difficult to get an even amount of flow to both front seat passengers.

i.e. Whoever has the top vent pointing towards them gets blasted, and the other get's sweaty!

Alan

Unfortunately this is normal - of course the top vent is the drivers vent (you can tell your wife I said so...)

Also the flow from the left 1/4 of the vent just hits the side of the pod and disturbs the rest of the flow directed at you - not realy useful.

Alan

blown 87

Make sure all the vacuum pods are doing what they are supposed to do.
That made a huge difference in mine.
I went from just what you described to some thing that is pretty nice.

Alan

Well even under the best of conditions its not balanced - but agreed if you have comb flap issues or sensor or weak AC issues this will be a bigger issue still for whoever get only the botttom vent.

Greg - feel the flow difference. Full fan - direct the top vents away from you and the bottom vents to you - now swap - you will feel a big difference (bigger still if the manual vent contol is partially shut). So make sure the vent door opens fully (really 100% horizontal)

I believe this is basically the same for all years - not just GTS.

The earliest cars had a different vent with no outlets on the left 1/4 - That is where the vent control **** used to be - I don't think it made any difference to the max flow and probably even had a more laminar flow to the face...

Alan

OJ GTS

Yep, had all of the vacuum system checked and repaired where necessary last year by a chap who knows the 928 system very well.

Oh well, nevermind, sounds like a 'feature'!

blown 87

I agree that there is a difference, heck there is even a difference in the temps at different spots in the center vents when not at full cold.
I was just shocked by how much of a difference it made having all the flaps working right.
Sounds like he has that covered though.

shmark

Not to be controversial, but I have a nice even flow coming from both top and bottom vents, damn near hurricane force. And temps from both are right above 32 as measured at the vent. In other words, of 4 cars I have the 928 a/c is by far the best and will freeze out both driver and passenger. I don't think unbalanced flow is correct, but it is common.

Alan

Well there must be some difference by year because my system is perfectly functional and extremely cold but does not have a balaced flow between top and bottom vents. I have seen this in other S4 cars too.

Your '83 has a different vent flap mechanism and has no comb flap so that may make a difference to the flow conditioning before the vents...

Alan

shmark

Certainly possible. I have not ridden in a later car with the a/c on so I can't confirm, but I am very happy with the a/c vents in my car. The only thing I wish were different is a later control head with the discrete a/c button.

the flyin' scotsman

The 'comb' behind the centre vent is supposed to help mix the output of the system. I personally find this more trouble than its worth so I deleted it.

Make sure you understand when this comb should and should not be retracked with a normal operating system before following my opinion.

After living in the frozen North for the best part of the last 30 yrs I prefer the default of the entire HVAC system to be cold..............the reverse of the Porsche design.