Quote:
Originally Posted by Zipforia
That's what I'm talking about. No matter how I position the vents, it can't seem to reach the head area; whereas my other cars can (including a minivan). At the same time, the AC howls like an Arctic blizzard.
Z.
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I study automotive engineering. I'm a physicist that has studied every make and model cars worldwide for 40 years (hobby). I have a BMW 335, 2008. It has a great air conditioner! They don't make them like this anymore, but MAX definitely helps (in addition it as head pointing vents in the upper dash that cools wonderfully and cools the dash which prevents IR from reflecting back in your face from a hot dash). I am looking at a 2015 X5. Unfortunately, the AC there is much weaker. Not terrible if you use MAX to get to initial coolness (could take up to 30 minutes, but usually 15, still too damn long). Car AC's to be effective requires the manufacturer to devote serious resources to designing it from the start into the vehicle and cover all needs from desert to 120 F in humid climates. I live in Austin, Texas, which is somewhere in-between. The fact is, an air conditioner at idle waiting in traffic is a poor cooler. With our congestion, that's where I spend most of my time. Compressor rpm's are low and airflow over the condenser is low. A bad combination. The only way to make an air conditioner adapted to that extreme environment is to design it from scratch to handle that. That requires properly sizing compressor output (needs to be able to control is rpm's independently of the engine, i.e. a compressor transmission). And the condenser and evaporators have to be design optimally for all conditions, idle/stop to full highway speed to cool even in 120 F humid environments. The only car I know ever specifically design to do that from scratch is the VW Phaeton (not available in the US). It was specifically designed to keep the car at 72 degrees even in 122 F humid environments (tested in Dubai, which is humid because of sea proximity). This was done only because the VW CEO Ferdinand Pieche personally required it. I'm sure it was remarkably expensive to make! So outside of that, all you can do is tint ALL windows. Including windshield and the moonroof. Solar radiation puts about 1000 watts of heat (equivalent to a 1000 watt space heater) in the car for each square yard of window (depending on the sun's position relative to the window). But maximum IR rejection is the most import criteria, not darkness (you can choose that as suits you, except the windshield must be clear). This will probably make the X5 OK. Still deciding whether to risk that. I HATE being hot when driving! Oh, the vents, yes there is a design defect in the wooden trim piece that covers over the front vents. The upper most vent louver in the upper most position directs airflow directly into a lip extending out from the front wooden trim piece. This causes air to be directed horizontally from the trim piece thus colliding with any upward pointing air from the vents. Technically, it could be fixed by increasing the angle of the taper on the trim piece over the central vent on a router table. Not sure the trim piece is solid wood, so if not then it wouldn't look right unless stained/painted to match. Kind of a pain. No, BMW will not declare this to be a defect. Anyway, hope this helps someone.
Again, I HATE being hot when driving!