DukecityWarrior

Hi, I am currently in the market for redoing my stock and dead AC system in my 1987 Trans Am. I was going to do a Murray AC compressor from O'Reillys and before purchasing I did some research saying the brand is a hit or miss. My question is, is there an alternative upgrade to a whole new system. I know that Classic Auto Care has come out with a system. Anyone have any input on how to get the AC in a third gen reliable and ICE COLD?

OdieTurbo

iTrader: (1)

I'm interested in this as well. In my research, I found this writeup: thirdgen.org/retrofitac

Lots of good info!

ternandes

iTrader: (7)

I would recommend that you consider upgrading your radiator and cooling fans as part of the job, if you have not already done so. Using a radiator with increased cooling capacity and configuring the fans to come on at lower temps will make a difference.

camaro_V6_Tuner

This is bull. the car had factory A/C and the condenser is in front of the rad. You won't have any cooling problems.

ternandes

iTrader: (7)

I speak from experience. The condenser being in front of the rad will heat the air passing through the radiator, and thus it helps to have extra cooling capacity.

DukecityWarrior

Thanks guys for all the information. I have heard different things such as upgrading radiator and fans and have also heard different things being said about the CHAMPION radiator brand. Any solid user feedback about these. If i was going to do such an upgrade it would be to a 3 core aluminum with dual fans. And how would you go about the fan configuration and making them come on sooner? Thanks again!

DukecityWarrior

After doing a little bit of research I have come across a Low Temp Fan Switch. Any suggestions about this application?
http://www.parts123.com/parts123/yb....ort~A2~cadefib
Part #: 244198

ternandes

iTrader: (7)

That's one option. I have used fan temp controllers that are available at local auto parts stores (Advance in my case).

They turn the fans on at lower temps and in my bird there is a significant difference in engine temp, especially at low speed and idle.

I had a Blazer some years ago with factory air that needed a radiator. It had always run a little too hot in the summer. When I upgraded from a 3-tube to a four, my cooling problems vanished, and YES, my AC ran colder.

My friend Justin (Justin98Formy) has the champion. Everyone who buys it says it is great. Justin says his engine temp NEVER went above 195 since he installed it, and he had a pretty awesome motor in that car (he's in the middle of an LS1 swap now).

You won't necessarily have any problems if you don't make these changes, but you stand to gain if you do.

zenish

i understand that 134a has smaller molecules and leaks out of r12 systems.also our cars condenser is too small for 134a to cool properly.maybe just hearsay...

topradman

If the engine is stock or not much more than, I would do as follows. Go with what ever compressor and receiver dryer at your local parts store that had a lifetime warranty. From a consumer stand point, this is the most reliable situation you can put yourself in as a "do it yourselfer". I would also change out the orifice tube to a "self adjusting" type. They are considerably more money but will help the 134 Freon behave better. When you go to put the 134 fittings on, remove the Schrader valve core from the original fittings if possible. We have had the most trouble with leaks when we depend on the conversion fitting stem to depress accurately on the old r12 stem. Many time they get "cockeyed" and bend the tip turning the whole job into a small pain in the a##. If your system has been out of use for a while or the compressor locked up, flush the system or have it flushed before you put the new parts on. Most warranties will require that you do this and replace the receiver/dryer/accumulator as well as the orifice tube. Do all this, fill your system with the same amount of r134 as what the capacity it for r12 and you should be fine. Oh, don't forget to put in refrigerant oil at the recommended capacity for your car as well if you do the flush. If you only do the components, follow compressor instructions for oil and also add about 2 ounces for the receiver/dryer/accumulator as well. Put the 2 ounces directly into this piece before assembly and of course, evacuate the system before attempting to recharge or it will not cool ( but I'm sure you know that ). The condenser will work ok with r134 however, if you end up replacing it, unless it is old inventory, the replacement will probably be more 134 compatible in that it will more than likely be a parallel flow instead of a serpentine flow. This does help make r134 work better but not absolutely required to get you back on the road.

Fast355

iTrader: (2)

Nope that is not hearsay at all. R134a creates less heat than R12 for a give high side pressure. Makes it more difficult to shed heat from the condenser in high ambient temperatures. If you want to run R134a you need as much airflow as humanly possible through the condenser and a blue or red ford orifice tube. Both will work to lower the head pressure which allows the suction pressure to decrease and the a/c to get colder. I prefer LS1 fans and motors in a dual setup with a full shroud. The LS1 setup is a fairly easy upgrade that makes for a very nice cooling improvement.

Fast355

iTrader: (2)

My experience with those variable orifices are they are JUNK. I had one come apart and get stuck in the evaporator. Unable to remove it from the evaporator inlet, I had to replace the evaporator.

As for the amount of refridgerant you specifiy, that sounds like a good way to nuke a compressor or at the very least blow a high side hose in hot weather. I start about 80% of the R134a charge and it works quite well. My brothers 1980 Corvette was cold with the stock system with R134a with only a blue oval orifice tube, but has a direct drive flex fan and factory electric puller fan and very little interior space. I would recomeend installing an aftermarket high pressure cutout switch into the control system to disable the compressor if the head pressure rises too much.

gp90gta

iTrader: (1)

Some good info here but I'd like to add.

One of the most overlooked ac problems is oil type and capacity, don't buy cheap oil, the right stuff is worth every penny.

I agree with not using a variable orffice.
Agree, use red or blue orffice.
Agree, flush system if contaminated, or just change everything.
Agree, get the best compressor and change dryer.
Don't agree better rad will help ac, I mean think of it, if a rad by its self no other changes to car or engine, if it lowers engine temp it's removing more heat from engine which means more heat radiating off of rad, that can't help ac BUT if you change things like fan on time, that would help engine and ac, by the way my car has stock rad and condensor and fans and even on 100* days I never go past 200*, fans set to come on at 170, ac blow just as cold as any of my new cars.
Agree a better condensor like a crossflow will help remove more heat from evaporator.

On a side note, I'm adding a large crossflow to a customers thirdgen, he has march pulley setup with a small sanden compressor, it's very small and very inefficient at rpms under 2000, it only pumps out 6cfm at rpms above 2000rpm, the stock r-4 I pumps out 10cfm, I'll post up some results when it's done.

topradman

I have installed variable office tubes in retrofits for years and never had a problem, in fact ac worked much better. Sorry you had a problem with your install, I never have. Never " nuked a compressor or a high side line either though i have replaced these parts from customer errors "AC Pro!" Do approx 50 - 100 ac jobs every year time permitting ( not all retrofits of course ) . Doesn't 87 have a high side cut out anyway?

Fast355

iTrader: (2)

Everything I have touched has ice cold air at roughly 80% of the R12 charge. More refrigerant and the compressor is going to start getting liquid returning to it. GM even reduced the charge amount on carryover systems when they starting going to R134a.

I don't quite do that many a/c jobs but I do know if you tried that here in Texas it would either open the 440 valve or constantly be cutting out on the high pressure cut out. The 91 Firebird I was around had a fan switch but no high side cutout.

I have used blue, red, and even smaller orifices for retrofits where lack of idle cooling is an issue.

topradman

Guess I'm lucky. Glad you have had so much success. Thanks for the info on the blue and red orifice tubes.

rusty vango

no,sadly r-134a SUCKS and mightily. and yes it has smaller molecules or whatever .and it WILL go away along with your not so cold AC. I have found that if you buy a receiver/dryer it has the 134 specific dissicant in it that is not compatible with r12. I have heard that r 406a is a replacement for r12 but I cant find anyone who has done the conversion. bottom line ...converting our 12 systems to run on 134 does NOT give satisfactory results

sjgrimsley

https://www.thirdgen.org/forums/cool...say-r134a.html

rusty vango

both are true,this is one reason a conversion to 134 never works well or for long.look at R406-A as a viable alternate