AC unit in 308/328

Seems that most of the guys attack the problem of inadequate Air conditioning with mechanical/electrical fixes, yet engine heat is alway mentioned. How about eliminating some of this heat with a heat barrier in the compartment, such as Dyna mat extreme.
I have the engine out in my 308 and intend to install this material before the engine goes back in the hole. Only my input and it appears to make sense to me. Cheers, Ken

 

The ac in my 328 worked reasonably well in my cross-country trip in August. I had to turn it down (warmer) in the morning and eve. But in the middle of the day (if sunny) it was bearable but not comfortable. I noticed that the compressor would cycle on-off even with the temp control fully clockwise. So basically what would happen is it would cycle on, after a short period the cabin would start becoming comfortable, then it would cycle off and the cabin would heat up again. In the middle of the day, this cycling could not keep up.

I was under the impression that if the control was fully clockwise, the compressor should stay on constantly. Is that how it is supposed to work? I have thought about "hard-wiring" the compressor to be on constantly but that may just cause the evaporator to ice up.

It seemed to me that the problem is that the air is quite cold right at the outlet/in the plenum. The temp sensor is in the plenum. So perhaps it cycles off because the air in the plenum gets cold enough to shut off the compressor but the VOLUME of air moving is insufficient to cool the car cabin. If that's the case, then, as others have suggested, greater airflow might be the answer. Has anyone yet found a reasonable way to increase blower speed that doesn't require reworking the entire unit? Seems that it might be possible to install a higher speed motor of the same external configuration that would just replace/bolt right in.

Anyone know if an elec motor shop could modify/rewind the motor to increase it's speed?

The car has a York compressor but since these same compressors were used in BIG US cars whose ac could freeze you out under any conditions, clearly the compressor itself is capable of freezing meat in this tiny cabin.

 

Further if it really is an air volume issue, I don't know anything about elec motors to know if this would work or not but my understanding of motors for different voltages performing the same function/rpm is that it's a matter of internal windings.

FOr example, bilge pumps for boats are commonly made in 12, 24, and 32v configurations. You can buy them in the same pump capacity - say 3700 Gallons per hour. They are exactly the same size. So is it the windings that make them the different voltages? If so, then changing the windings at the same voltage should change the motor's operating RPM.

If the oem motor could be speeded up, it might resolve, or at least, improve cooling without needing any "exotic" mods. ???

 

Does anyone have the physical dimensions of the oem ac evaporator blower motor and the RPM rating? ANyone have a pic of it?

I've been discussing this via email with an elec motor rebuilder guy in Annapolis. His opinion is that while rewinding the motor could be useful, he thinks that it should not be difficult to find a 12v motor with the same physical dimensions/setup but with a much higher RPM. I told him I would bring in my motor to physically match up but can't do that until mid Dec when I'm in the area.

Might be able to be done with dimensions/specs alone.

 

If, on a hot day, the compressor keeps cycling at idle it is likely that your system is undercharged. If fully charged, the cycle switch my be off spec. Having never seen a 308 Ferrari cycle switch, I do not know if it is adjustable, but many OEM GM cycle switches are. In an R-12 system, the compressor should switch off around 32psi thus keeping the evaporator just above freezing. 134A will need to cycle off at a higher pressure (I have a chart around here somewhere) but the end result will be the same, the evaporator should be kept right around 32*-33* so that it won't ice.

Shiny Side Up!
Bill

 

There was another F-chatter who was refabricating various parts of the 308 a/c system. Actually had some really nice drawings and specs for an over-sized condenser. He also got a beefier blower motor replacement (from SPAL) for the evaportator. Last I messaged with him he said he was going to produce some of the condensers for sale.

 

Any updates on this??

 

I have a thread I started on my "308 AC refurbishment". Search this and it has my progress so far. I found a larger blower motor that gives me one additional higher speed. (middle speed equals my old hi-speed). Also used Nick's Forza Al radiator and new aluminum cross-flow condenser. Still need to take vent temps. Also need to come up with a better way to vent from the outlet underneath radio. That blocks WAY too much airflow. But so far a great improvement.