BACooke

I'm thinking of upgrading to R134A using RennAire's system but I know nothing about their ProCooler re: effectiveness & installation. I have an '88 Carrera with the Nippondensa compressor that I'd swap with their Sanden 507 compressor. Any thoughts/comments?

1986 Targa

We installed both the ProCooler and the High flow evaporator in our '86 R12 many years ago,

Can't say enough good things about RennAire.

We have center vent temps of 45-50F on the freeway on a 95F day.

I would encourage you to keep the R12.

Hope this helps.

Gerry

rusnak

the Pro-Cooler is ingenious, and works very well.

However, I would caution against converting to 134a. I would probably spring the extra bucks for good hose, and have it re-filled with R12.

Ed Hughes

I have no personal experience, but I knew guys in TX, who had good luck with their stuff. You may also want to look at Griffiths, who is a sponser here, about upgrades. They know their stuff too.

Ed Hughes

Wait, Vancouver?

How bad do you need a/c?!

griffiths

The Denso 10P15C (stock, factory) has a greater displacement than the 507, so
that part of you choice is not an upgrade. If your compressor is shot, I'd just drop in another 10P15C Denso.

If you have a SC with a York, then my first choice would be the 507 simply because of ease of fit.

You can use a 507 in your 88... but 'someone' is marketing you a downgrade simply because of their cost.

wwest

The ProCooler is only functionally operative(***) once the cabin has cooled down to your satisfactory temperature comfort level. The ProCooler works via using EXCESS refrigerant cooling capacity downstream of the evaporator to "pre-cool" the liquid refrigernat before it reaches the expansion valve. If the entire cooling capacity of the refrigerant is used up in the process of keeping the evaporator CHILLED (ALWAYS the case during initial cabin cooldown) then the ProCooler is simply additional weight.

Once the cabin has been cooled down to your comfort level you are most likely to retard the compressor dutycycle yourself(***) and thereby reduce the need, usefulness of the ProCooler.

You may wish to note that the compressor highly recommend by the aftermarket "snake docters" has a lower pumping capacity vs your OEM compressor. Just yet another way to insure you will be buying additional upgrades.

The base question you must ask yourself is this:

"Does the OEM system cool the cabin down to your temperature comfort level reasonably quickly and then adequately keep it at that level on a hot and humid day during a long highway drive with the engine RPM consistently high, and good airflow over the front condensor?"

On my '88 Special Edition, Diamond gray in/out, the very first thing I did in this regard was side and rear window tinting.

I next followed Porsche's lead in that they added additional refrigerant condensor capacity (front condensor & fan) as one of their first efforts in improving the A/C cooling capacity.

Oh, sidebar: It cost me less than $200.00 to have the system converted to R134a by a professional A/C specialist shop.

Following Porsche's "lead" I looked first at methods for improving the refrigernat condensing capacity. That led me directly to the fact that the OEM capability is significantly limited by the amount of airflow through the rear lid condensor when the engine RPM is consistently low or even mostly idling.

After a few trial and error efforts I ended up with a quite satisfactory system. More prone to freezing up the evaporator in certain situations, traveling over >3000 ft mountain passes, than I would like, but certainly more than adequate cooling.

I have two 12" radiator cooling fans mounted under the rear lid condensor along with a tri-function high side refrigerant pressure switch.

The 2 primary functions of the pressure sensor switch is to prevent the compressor from operating at all with a low refrigerant charge, and second, to limit the high side pressure level to which the compressor might otherwise drive the factory system.

The 2 fans are wired to run in series ("half" speed) unless the third switch function indicates that the rear lid condensor requires a cooling BOOST, in which case the fans are switched to run in parallel, FULL speed.

The fans will continue to run at full speed even with the ignition switched off provided the condensor pressure remains, or become, elevated.

*** Then why do ProCoolers even exist..??!!

To know that you need to understand why/how modern day automotive climate control systems operate the A/C compressor's cooling capability 24/7. In that (unique?) situation the ProCooler might well yeild a 10-15% compressor dutycycle reduction, thereby a not insignificant FE improvement.

wwest

The issue of non-barrier hose vs otherwise might well prove to be an oxymoron. The refrigerant leakage might well be the result of high side pressures rising higher than the design specifications of the non-barrier hose or even the seals or hose couplings.

Considering the factory design: Should the thermostatic switch controlling the compressor cycling be mal-adusted such that the compressor continues to be cycled on even with the TXV mostly closed the high side pressure might well exceed the system sealing design criteria.

1.) You MUST be careful that the thermostatic control switch is adjusted to keep the compressor cycled OFF once the evaporator core temperature is below 34F. The TXV (expansion valve) design/setting is such that the refrigerant flow into the evaporator will be SEVERELY restricted if the evaporatior outlet is CHILLED below 34F. Should the compressor continue to cycle on in that situation then the high side pressure might well exceed the system sealing limit.

Yet another reason why everyone most heartedly recommends at least a binary pressure switch to disable the compressor should the high side pressure reach the high side pressure switch limit.

2.) There is a fairly unique, possibly rare, situation that might result in excessive high side pressures. Turn off the ignition on a hot and humid day with the TXV already restricting evaporator flow (the evaporator core FULLY CHILLED, <34F) and the heat rising from a HOT engine might well result in high side pressures exceeding the design limit. These decidedly rare situations might well result in a long duration period, ~2 years, for loss of enough refrigerant to require a recharge.

Nothing I have said really rebutes the idea that converting to modern design barrier hoses, and incidentally new seals and couplings, would not also be a satisfactory solution. But keep in mind that these same hoses that seem to leak in the Porsche application were also used throughout the industry during that same period with absolutely NO indication of this type of problem.

wwest

HUMIDITY...!!

And just barely stateside you only need to drive EAST about 100 miles to reach HIGH DESERT climate.

griffiths

LMAO....LMAO

rusnak

I would think that a desire to increase the cooling capacity of the condensors would lead one to move said evaporators into an airflow away from a heat source. The engine and exhaust turn the back of the car into a 1,000 lb heat sink, and pretty much render the condensor ineffective. Not to mention pre-heating the cooling air and intake air, resulting in much higher yet engine and oil temps. All that heat....talk about pressure.

Anyway, the ProCooler does work up until the point where the condensors simply can not reject enough heat. It uses wasted cold to send less (LESS) HEAT back to the condensor. Just think on that for a second.

wwest

Took more than a second....

My understanding of the ProCooler is that it uses EXCESS cooling capacity to "pre-cool" the LIQUID refrigerant before it enters the evaporator via the TXV opening. EXCESS cooling capacity being that leftover in the refrigerant OUTFLOW from the evaporator. So, with these system designs WHEN is there leftover cooling capacity downstream of the evaporator...?

Certainly NOT during initial cabin cooldown with the TXV fully open due to the HEAT load on the evaporator..!

But what about after the cabin has reached the desired comfort level? In that case isn't the proper method for managing the system is to retard the compressor duty cycle? Turn down, effectively, the cooling capacity of the evaporator thereby forcing the TXV to remain mostly open..

And FINALLY....

In actual useful environments the ProCooler serves to add MORE HEAT to the gaseous refrigerant entering the compressor, actually ADDING load on the compressor. In A/C environments

rusnak

I just noticed that my edit never made it to the board. I meant to say that you would move the condensors, not the evaporators, into a clean air stream. I have always thought that a front mounted condensor would be the ultimate way to go.

BACooke

I don't text so I have no idea what LMAO means. I'd like to thank everybody for their input. I have bitten the bullet and have ordered the complete upgrade kit with new Nippondenso compressor from Griffiths. I might not get a chance to install it till May but I'll post the results. Someone mentioned the temperatures in Vancouver and I must admit to being a bit of a West Coast wimp BUT I only have to drive 150 miles and the temperature does get into the 90's. Thx again

User 123

Griffith's install on my 89 Coupe is about to begin.... stay tuned for update this summer when temps pick back up.