Air conditioner condenser vent - 328

Today, for the first time, I actually was looking at the condenser with the system on. With the "hood" open I noticed that a lot of hot air pulled by the condensor fan was blowing up into the hood area. I realized that the louvered vent mounted in the passenger side wheel well behind the condenser doesn't pass very much air. If you remove that vent panel, there is a large increase in airflow.

It seems that a heavy mesh (1/4" or larger screen would be a lot more effective for cooling than the oem vent. Has anyone tried that? I was thinking about running the car without the vent but I'm a little concerned about "large" debris being kicked up and damaging the condenser. I don't know if it would make any difference in cooling capability but it seems to me that a much greater airflow across the condenser might result in better cooling at all speeds.

 

Well, of course there is no way to tell the effect at speed as far as lift/aerodynamics are concerned anywhere around here! But the airflow through the condenser with the vent removed is probably close to double what it is with the vent attached. This AM I ran the a/c with the vent on/off at idle and the air at the center dash vent was noticeably cooler with the condenser vent removed. I don't have a thermometer so I can't say how many degrees that actually was.

Then I drove around with the condenser vent removed. I couldn't tell much difference in the performance but the compressor was short-cycling which normally indicates a low charge. So on Wed I am having the system serviced (vacuumed/recharge) so that will give me a better idea of the actual difference the vent makes, if any.

The system was last serviced in '08 and though I have had US cars that never needed service the entire time I owned them, we all know that 3x8s are not famous for robust ac and I suspect the performance will improve at least a bit after the service and it will give me a better starting point re the vent. It seemed to work better last year, especially when I learned that the ac is most effective with the dash vents pointed at the windshield. But in the last few weeks here with some 90 degree days and high humidity, it is not working well at all.

"shall we trust Pininfarina/Ferrari on this?"
No, I wouldn't. European ac in general was pretty poor performance-wise compared to US ac back then. In Ferrari's 3x8 case, the ac is more like a late 50's US add-on (like the Mark IV Monitor of that era) than an actual engineered-in ac unit. It seems obvious that the system was put in to satisfy the marketers, not to actually run you out of the car due to the cold. When you consider that the same York compressor in the 3x8 was in Chrysler imperials and WOULD run you out of the car, it is clear that the system is very poorly designed from an ac capability point of view.

IMO, (and I'm NOT an ac expert) the lack of flow through the condenser and the lack of flow from the cabin fan is the issue.

 

Today I had the ac system serviced. On the way to the shop (60 miles each way) between 8:30-9:30AM the outside temp was around 80 with a good bit of humidity and it was uncomfortably warm in the car all the way with the compressor cycling on, running for about 20-30 seconds and then off for a while, repeating this all the way. On the way back, between 12:30-1:30 with temps in the mid 90s and worse humidity the compressor stayed on most of the time and the cabin was "not bad." I would have liked it a bit cooler but it was not uncomfortable at all. The ac performed better than it did the last time I had the system serviced and I believe this is due to removing the vent which provides greater airflow through the condenser.

I now believe that the best way to increase ac cooling is to change the oem condensor from a multiple-level coil unit to a larger, single coil unit that could mount in front of the oem coolant radiator. Seems to me this wouldn't be too difficult to do and, at least in the 328, there is plenty of engine cooling capacity to handle a condenser in front of the radiator. The oem condensor has several sets of coils behind each other so it is much less efficient than a larger condensor with a single level of coils.

I don't know if I am interested enough to actually pursue this but IMO, trying to make/find a "better" condenser to fit in the oem spot is pointless. The limited space REQUIRES a condenser with multiple layers of coils which automatically means that only the first set of coils gets "cool" air. I think any custom ac shop could come up with a suitable condenser and mount it nicely in front of the radiators. Or just purchase a condenser for a typical US car and that would probably do the job just fine.

 

"When I redid my AC a few years back with a new compressor, the AC shop told me we had to have the hood closed so the fans would blow through it otherwise it all goes out the top."

The fan pulls it through the condenser so no matter what, air is pulled through. The problem is that because of that louvered vent, the air cannot escape as fast as the fan can pull it so the flow is reduced. Opening the hood actually helps the airflow through the condenser, giving the air a larger outlet that it doesn't have with the louvered vent in place.

The louvered vent is a problem. I did some more testing today and removing the vent makes a noticeable difference. With the vent installed and the car stopped, the cabin starts heating up immediately (condenser fan working fine). With the vent removed, the cabin stays cool when stopped. I then tried running down the road with/without the louvered vent installed. The cabin was able to withstand the direct sun, 95 degree heat and high humidity without becoming uncomfortable. With the louvered vent installed, it became decidedly uncomfortable. As I said, even without the vent it is not going to freeze you out of there but it certainly made the difference between sweating and not.

IMO the most immediate improvement to ac is to remove that louvered vent.

 

I got a PM from someone telling me that I was full of fecal deposits and that removing the vent cannot help and may hurt. So I thought I'd respond to that publicly:

Well, instead of calling me an idiot or whatever, Just remove the 6 screws that hold the vent and try it for yourself. It takes maybe one minute to remove it. Then, with a PROPERLY charged and operating ac system, see if it helps or not. Doesn't cost a penny to try it. However, if your ac system is not fully charged and/or otherwise operating properly, then removing the vent probably won't make any difference.

Also note that my post was about a 328; I have no idea if a 308 is setup the same way and with the same ac components.