?'s for the a/c guru's

[bigchillcar]

scott,
thanks. do you know of anyone who simply performed a single, direct replacement of their old r/d unit with a procooler and documented what the effect of this single upgrade was? i know i've read about upgrades including a procooler when other things were done as well..you know what i'm asking..
ryan

[scottb]

That's always been the unanswered question. I did a lot of other upgrades, so the PC was just one piece of a bigger picture. I'm happy with the results, but can't document how much of a role the PC played in the improvement.

Scott

[patkeefe]

BTW, Jim, that is a nice install you did on the return fan setup for the evap.
What is this precooler, or subcooler, being mentioned above. Is this just another condenser?

[scottb]

Pat: It's a subcooler. It replaces the receiver/drier.

Scott

[Hugh R]

This thread has pics of Jim Sims subcooler. I made one following his directions and the hardest part was figuring out where to stick it. I put it just outside the back of the skid plate. You have to measure carefully when making the hoses. Here's the link Barrier vs Non-Barrier A/C hoses

[bigchillcar]

yeah, that's the thread i was referring to..thanks, hugh. btw, what are your own impressions of the job it's doing? i seem to recall you making several component upgrades at the same time though, right?
ryan

[Kemo]

Right now...my SC is down at Rennaire getting the new Evaporator and Barrier Hoses like Mark Wilson.

When completed, I will have just the stock rear condenser, Pro-Cooler, upgraded evaporator, new barrier hoses with a sanden compressor.

I will post the final results in the TEXAS heat, >95 degrees in full sunlight on a hot road in Dallas traffic. That should be a good indication of the cooling power of this affordable combination.

[bigchillcar]

kemo,
that will be interesting data..new hoses shouldn't affect vent temps, but we do know it will save refrigerant charges for sure..can't say what a new evap will do (anything about the new evap an upgrade over the original?). i have the same sanden and stock rear condenser as well..i'm anxious to hear your results. did you take baseline vent temps by any chance before leaving the car at rennaire?
ryan

[Hugh R]

Bigchillcar

I'm not where I want to be. My car is an ROW without factory air, and has very different ventilation plumbing behind the dash than a US car with factory air. So first off, I'm not getting the blow that I want out of the vents.

Second, I'm probably going to take out the fan-powered condensor next to the catalytic converter. When stopped, that condensor see over 120 degree air and it can't be cooling, in fact, I think its adding heat to the R134a in the system. I may or may not put that condensor in the front left wheel well, I have to see how much room I have in there with the washer bottle romoved, the condensor is 12" by 12" by about 3" thick with the fan.

Three, I tried using a couple of computer fans in lieu of the real Behr front condensor fan. I may spring for the $250 new one if I can't find a good used one. When I'm driving at speed I get around 40 degrees at the vents, when its 85 outside. The problem I have is in traffic when vent temps go up to 60 degrees.

How well does the subcooler work? I don't know since I don't have a "before" and "after" Jim Sims says it only works if you have excess condensor capacity, I'm not sure what constitutes "excess" perhaps more than just the original two condensors. Jim Sims recommends that I get a REAL vacuum pump and not one of the venturi air compressor types and run it for several hours with the car out in the sun. I may try that as well. $250 for a front condensor fan, $210 for a vacuum pump, about $100 for 134a gauges versus paying someone to do the pump and recharge, hmmmm.... the wifey is (not) going to be pleased.

[bigchillcar]

hugh,
trying to recall..are you the one with the thread about putting a condenser in the driver's side rear wheelwell? you tried computer fans but now considering the fan typically used in front wheelwell condensers as i understand it? do you have a fan for the rear deck condenser? i know if you have cis, you must have modded the airbox for fit. what's jim's story with vacuuming the system out? starting over fresh?

as for the wife..what she must understand is that this is not only an important upgrade for your car (can't have hubby having a heatstroke while driving), but this is important research for your fellow man and p-car connoisseur..
ryan

[Hugh R]

Ryan

I had some computer fans on the rear condensor when I had a non-stock really small condensor, but not since I bought a full sized condensor, I may put some back on, they helped in traffic. I do have computer fans on front condensor, but may buy a real squirrel cage unit ($250 new), I have an 84, so no cis. Pulling a vacuum is to start fresh, but Jim thinks that the cheap ($20) venturi-type vacuum pumps that work off of a compressor don't pull enough vacuum and that you'll get better performance (colder temps) using a two stage vacuum pump.

I may put a condensor in the l/f wheel well, if the one that is currently next to the cat. have fits.

[Kemo]

Originally posted by bigchillcar
did you take baseline vent temps by any chance before leaving the car at rennaire?
ryan

unfortunately I did not. Im sure someone out there will have a stock A/C system out there to compare to. If I can have 30-something temps comming from the vents in traffic during a Dallas heat wave, I will be very happy.

[Jim Sims]

Subcooler doesn't replace a receiver/drier but can be combined with it (as in a Procooler). I estimate I am gaining 10 to 15 degrees temperature drop over system without subcooler. I just took my car on a 3100 mile trip and A/C worked well everywhere (down I5 from Davis to LA - there was plenty of humidity), in downtown Hollywood traffic and charging up Cajon pass out of San Bernardino, in Needles, CA in mid afternoon and across AZ and NM. Jim

[bigchillcar]

jim,
b4 i renovate this fall by replacing hoses and r/d (maybe adding subcooler)..i guess you would still highly recommend vacuuming everything first b4 taking apart, then performing the upgrades? even replacing the r/d and hoses it would probably be benificial for the condenser, compressor and evap i'm guessing. i know where to mount the subcooler, but again, between what components inline do you put it?
ryan
ryan

[Hugh R]

If you have R12 have it pulled out and recovered at a shop. You pull vacuum just after you've connected everything together. Keep the new r/d sealed until just before you connect. Subcooler has two pipes with four openings. You connect the two big ends to the big hose between the evaporator and compressor, and the two small ones between the r/d and the expansion valve on the evaporator. you'll need a flaring tool that can accept a big enough piece of copper tubing 1/2" or 9/16" I don't remember, you get the flare fittings at Home Depot, Loews, etc. in the little speciality fittings drawers. You have to use flares on the subcooler, because you can't find o-ring copper male fittings to hard solder to the subcooler.

[Hugh R]

Just got loaned a real vacuum pump, gauges and a big jug of R134a, for free (actually a dozen donuts)!!

[bigchillcar]

good buy for donuts.. thanks for the info, hugh..i can see i'll need to do a little more studying and figuring where addition of a subcooler would be involved.
ryan

[Hugh R]

Rats, gotta buy a 134a fitting for the vacuum pump. Gotta find an A/C parts supply shop tomorrow.

[bigchillcar]

shoulda bought chocolate instead of glazed, hugh! penny-wise and dollar foolish..
ryan

[Border911Dude]

I'm going down this trail to upgrade the a/c in my '79 SC. The front condenser blower requires at least a new motor.



I'm considering enlarging the penetrations in the front of my tub to accommodate a 9" fan. It's specs are 3.5 amp, and 1400 cfm


Questions are:
a) would this be an improvement?
b) would such a modification "damage" my car? (Non-stock kludge!!!)

Thanks