sumdewd

Scroll all the way down for my questions... This is just back story.

I live in Florida. Summers get way too hot here to go without A/C, so I fixed it and retrofitted. Turns out the retrofit sucked.. I wasn't surprised, so I managed to upgrade to a parallel flow condenser in my '90 Si. The A/C got better but would still do only 64f at the vents at a stoplight with R-134a. The car is white and has tinted windows. Both fans work and the condenser is sealed to the radiator on all sides except for the bottom.

The entire system is brand new and was assembled by a master technician. It has exactly 5 ounces of BVA auto 100 oil (R-12 compatible I think) TOTAL and refrigerant charge was played with until best vent temperature was achieved. (Has to be done this way on a custom system)

I also remember reading a thread a while ago about people searching for a way to use a stock parallel flow condenser... I can also shed some light on my install. I had to do NO custom piping, just bending the living crap out of the existing Receiver Drier piping because the fittings were the same on both condensers.

This condenser will work in our cars with alot of Receiver drier pipe negotiating (bending):
https://www.ackits.com/pc/12-0439D/P...+%2812+X+23%29

The fittings are the same on the OEM condenser and the Parallel flow. No need to change the fittings with a Matsushita system. I am not sure on a Sanden.
BEND THE RECEIVER PIPES AT YOUR OWN RISK!! BEND THE PIPING OVER SOMETHING ROUND OR IT WILL CRUSH ON ITSELF

I don't have any install pics, but I can get pictures of how my pipes are routed if somebody wants them the next time I take my bumper off.

As for mounting the condenser, it is mounted easily using the universal brackets included. It's mounted fairly solid. Once again, I will get better pics when I take my bumper off.

So finally, my questions for you R-12 peoples:

Is your stock system with the serpentine condenser great with R-12?

Should I bite the bullet and upgrade to R-12 combined with my parallel flow condenser and have awesome A/C?

Would high speed Spal fans help my A/C greatly even without R12? My condenser fans seem weak compared to my friend's Spal fan. A/C only sucks at idle (64f) and gets down to 48f while driving.

Install fans, swap to R-12, AND use parallel flow?

P.S. I can find R-12 for 20$ a can on CL. Any input is appreciated!

steeltoe

i have a 91 civic and I redid my entire ac system recently with new oem replacement parts and a rebuilt compressor. I'm using 134a. now that the temp outside is 100 it doesnt blow cool enough (especially at idle) and I need to do something about it.

did you do the changes you were inquiring about and how is it working for you?

I wonder if the oem 94-97 civic parallel flow condensers has a better fit than the ackit universal one that you used.

like this one:

http://www.stylintrucks.com/parts/pr...i7014540-.aspx


I was going also consider using envirosafe hydrocarbon refrigerants, particularly the Industrial 12a from here:

http://autorefrigerants.com/co00033.htm

it's supposed to be cooler than 134a.

hope someone can chime in as well thx

sumdewd

I don't know what to say dude. This system hasn't been working very well at all. My friend's sunfire will do 40f at the vent all day and we rebuilt that from scratch. Meanwhile, my Si only does 50f while cruising and creeps up to 65f at a stop. That's with the PF condenser and R12 which really pissed me off because I did all of that to make it cool.

I have yet to put my gauges back on it. I believe my fans are shitting out and running slow, though. School and work has been very hectic. When I figure it out, though, I will post back here with my results. Which will be soon because I can't take it lol.

I will mention that you need to adjust your heater valve. I was able to cool 5-6 degrees better at the vent when I adjusted the heater valve off when the **** is all the way cold.

Edit: Don't bother with the alternative refrigerants. They blatantly say to underfill or overfill systems. I think they're all full of it.

Double edit: I am running R12 with this system and parallel flow. I did not upgrade the fans. But I didn't check the pressures to see how it was doing either. I charged it in march when it was only 84f ish out. Now that it's 96, it's not working so great. I will update this when I get the chance to look at it.

94eg!

iTrader: (2)

I just installed an aftermarket parralel flow condenser yesterday. Got it on ebay for $40 shipped. It was made to be a direct replacment for the stock EF unit. Only problem is the little tube curving out to the bottom pipe fitting sticks out and hits a bit of the core support running right in front of it. I had to bend the support a little bit out of the way (the side running vertical up to the headlight). After that mod, it dropped right in. I didn't have to monkey with the pipes hardly. The one that mounted to the bottom required only a little tweak to meet up, but it wasn't too bad. I won't be charging the system till this evening so I'll get back to you on performance



As for fans, I've had to replace BOTH my fan motors in the rex several years ago. On one, I swapped in a used fan. On the other, I went with an aftermarket fan motor that I spliced into the old harness cord. Both seem to be good & strong now.

BTW: The CRX system holds a lot more refrigerant than most honda systems. According to Sanden, a R134A conversion should use 5% less refrigerant (by weight) than R12. With R12, the system holds 900g +/- 50g. So with R134A, your looking at ~850g +/- 50g. That's 2.5 cans of refrigerant. I never knew this so I'm quite sure I was always under charging (only using 2 cans).

As for oil, the Sanden compressor system uses 120cc total. Matsushita compressor system uses 130cc total. If you've retrofitted R134A, Sanden says to use PAG-46 instead of Ester. Just be sure to get the premium kind that advertises being Double End Capped. Otherwise it's just crap PAG that reacts with water and becomes useless.

sumdewd

An update would be much appreciated with that condenser. I need to slap the gauges on my Civic sometime and get pressures. Only then will I know what it's missing.

steeltoe

wow thx for that info 94! cant wait to see how it works for you.

sumdewd, here are some things to consider:

did you have all the hard ac lines cleaned out well? if they're dirty it may cause issues.

I would question the R12 source, that price does seem way too low, could it possibly be counterfeit?

would a parallel flow condenser make the r12 run worse than the original design?

did you have the ac lines rebuilt with barrier hoses? if not your 134 would leak out in the long run if not sooner than later.

here's a getto mod idea I've had for awhile: when i was charging my ac system it said to spray down the condenser with water to get the temps down to able to add more freon quicker...it gave me the idea of rigging a way to be able to spray a mist of water while at idle..when the condenser fan blows it'll release more heat when its wet rather than dry. of course this will be done from the inside of your car with a push of a button

i wouldn't dismiss the hydrocarbons just yet..i had a really great article posted somewhere on some guys with rx7's that lived in the south and nothing worked better than the hydrocarbons...i'll post the link when i find it.

zrickety

iTrader: (1)

I have the envirosafe industrial 12a, though I have not tried it yet. Still running on 134a and only one radiator fan. I haven't measured vent temps, but it does get cold. The dash and interior get pretty hot in the Georgia sun, and it takes awhile before the dash itself is cool to touch. I have a B16 and newer Denso compressor designed for r134a. Your friend's sunfire was probably designed for r134a as well. I wonder if the older compressor can't sustain the higher pressures needed?

sumdewd

My whole system was rebuilt and I'm still running R12. The little bastard can put out pretty high pressure if it wants to.. Trust me

Edit: Cans were rusted and were old dupont cans of R12. I don't need barrier hose for R12. Every line was flushed clean and the system has a new evap, expansion valve, condenser, compressor, drier and thermostat. Oil was weighed in. Dunno if the PF condenser could make it worse. I would think that better heat exchange overall would work better no matter what... And the only problem with the water idea is eventually rusting/corroding the condenser I guess. Then again, I do drive in the rain alot and my condenser doesn't care.

94eg!

iTrader: (2)

Put the vacuum on it last night, held for the required time in the manual. Then I let usual amount in through the high side with the engine off (per the manual). Shut the valves off and wen to fire up the AC, and the clutch & condenser fan won't run.

Looks like I've got to track down some electrical bugs.

BTW: More condensing capacity "should" lower the high side pressure since it makes the charge cooler.

91 EF DX

check the relay

94eg!

iTrader: (2)

It's a blown #38 fuse. I hope new fuse fixes problem. Can't test till this evening.

steeltoe

okay i found the link:

http://www.rx7club.com/3rd-generatio...e-12-a-664882/

i also just found this:

"you might want to think about adding a small electric fan on the condenser, wired in so that it kicks in when you press the a/c button. This should help should you be caught in stop and go traffic. My father did to his GSL, and the a/c is ICE COLD even in the Texas heat, and Florida humidity.... the windshield develops condensation lol"

i got the above info from here:

http://www.rx7club.com/1st-generatio...gerant-849574/

so it seems like a great idea to get the biggest pull fan you can fit and rig it so that it is ALWAYS ON and should help at idle like mentioned above.


btw sumdewd i found your thread, great idea on sealing the condenser!

http://www.autoacforum.com/messagevi...AR_MSGDBTABLE=

what i'm doing:
before i attempt to use a parallel flow condenser I'm going to upgrade the pull fan and rig it to stay on and seal my condenser to the radiator. then i may change freon to r12 or industrial 12a.

btw i did insulate my suction line when i put everything together..maybe thats why i get slightly better vent temps than you?

the search continues.........

sumdewd

I believe I know where I went wrong. I stopped right at 2 cans to clear the sightglass and didn't follow up with checking the low and high side pressures afterward. I was rushed and headed out to work. I seriously need to slap gauges on and check. I still don't have any leaks because I have the UV BVA auto 100 oil and a blacklight search reveals nothing.

And yes, the condenser sealing helped a whole crapload at idle. So did the heater valve adjustment. But i'm still not at good vent temps here in Florida.

I still need to do a before and after test for insulating the low side lines. Once again, I have no time.

steeltoe

yeah the factory manual calls for 30.1 - 33.6 oz of R12

cant wait to see

zrickety

iTrader: (1)

2 cans won't be nearly enough, especially with the extra condenser.

94eg!

iTrader: (2)

Well I just got my CRX charged and working. According to the manual, the stock system needs 900g +/- 50g. Then according to Sanden, you want 5% less by weight when using R134A. That means ~850g. So that's exactly what I put in. I used a digital scale to weigh the cans during the process. It literally took ALL 3 cans to get 850g into the system. And that was using a pan of hot tap water to force the can to empty faster. Once finished, two of the cans were dry and the third only had a splash still inside. Seems you don't always get what you pay for (they advertise 340g each can).

The parallel flow condenser I pictured above seems to be working great, but I haven't taken the car for a drive yet. Here are my measurements taken at idle sitting in my garage (doors open, AC on max):

- High - 175psi
- Low - 30psi
- Outside temp - 95*f
- Outside Humidity - 8%
- Vent temp - 41*f

According to the manual I was supposed to get measurements at 1500rpm. So I plan on re-doing them another day and checking against the specs in the chart.

I can't wait to get real-world reading tomorrow afternoon. Should be over 100 here in Reno.

94eg!

iTrader: (2)

If your talking about the sight glass on the gauge-manifold: If you are charging through the low-side with the compressor running, and properly keeping the can facing up (gas only), you will never see anything appear in the sight glass whatsoever. With the compressor running, the low side does not enough pressure to make liquid refrigerant. This is why it draws everything out of the can.

It's not a good idea to fast-fill the system by tipping the can and forcing liquid refrigerant into the low-side. If you get too much at once, it can damage the compressor. The trick is to get a shallow pan with hot tap water and sit the charging can in it. This will keep pressure up in the can as it tries to get cold. Pressures only rise slightly when you do this, but you will find your can empties quiet fast and doesn't create any dangerously high pressures. The funny thing is your water will be totally cold by the time the can is empty.

I added all 3 cans of 134a (850g), and never saw a single liquid drop show up inside the manifold sight glass while charging the low-side (compressor on).

Now if your talking about a sight glass on top of an OEM receiver/drier, that is another story. On the high side AFTER the condenser, the refrigerant should be completely liquid with zero bubbles. Of course aftermarket receiver/driers don't have a sight glass (cheaper). This goes for my 4-seasons drier.

94eg!

iTrader: (2)

Tested today....

System wags between 40 and 44 degrees. Evaporator core thermo-switch shuts the compressor off when vent temps drop to 40, and clicks back on once it rises to 44 again. Vent temp won't get down to 40 unless the car is actually moving though (only ~42). It's nice because the system cycles on the freeway now even at max fan speed. It would never do that before. In fact, it wouldn't even cycle at 3 before. This should help save some fuel now. I don't know if it's because of the parallel-flow condenser or the full 3-can charge though. Maybe both.

All in all I'm happy. Hope it all stays inside from now on.

DCRB

damn. most of this is over my head, but i'm book marking this for my accord, which currently the ac doesn't work in

sumdewd

The receiver sightglass, yes. And those are some excellent temperatures. Mine would only do 45 in the morning while cruising. Lowest during a sunny 95f day is 56 while cruising. AFTER the car cools down.

And to top it off, I believe the evap switch shuts it off at 50 on mine. Just what I need lol

94eg!

iTrader: (2)

Oh... Maybe you need to replace that switch. It's just so lame that you have to remove the core to install the thing. Another thing you could try is simply pulling the plug from it and sticking a paper clip in it. This will trick the system into running continuously. See if that brings your vent temps down towards 40. Also be sure the paper clip won't short out on anything while it's dangling there exposed.

Also double check your thermometer is working properly.

James89DX

sumdewd, I didn't realize you had made a thread over here. Sucks to hear you're not getting very good performance. Mine is still working pretty well.

94eg! - could you clarify those temps some? A little background on mine - completely rebuilt my system earlier this year, even got new rubber lines and pressure switch, everything. I installed two Hayden fans in front of the condenser (I posted pics/more details here http://www.autoacforum.com/messagevi...threadid=23479).

Anyway, mine will get down near 40 degrees while driving, even on HOT days. However, let's say it's 100 degrees out and I go out to my car and start it up and turn on the AC. It can't cool itself down below 60 it idle. However, once I start driving, it will within a few minutes get down to 50, and after about 7-8 minutes will get down to 40 while driving. Once I stop at a stoplight, though, it climbs up to 50 and will maintain that for several minutes. If I sit idle for 10-15 minutes or so, it will eventually climb up to 60 and sit there until I start driving it again.

So, are you saying you can start your car up (outside, not in a garage), turn on the AC, and sitting at idle (not having driven it), it can sit there and cool itself down to 40? If so, that is crazy!

94eg!

iTrader: (2)

No that's not what I was saying. Temps were about 85-90*f outside when I went driving yesterday. I think the thermometer read 105-110 when I sat down in the car (sitting in the sun @ 9am). Had the vent set to fresh air, with the fan on level 2. The road outside my work is 50mph. I think I went ~45mph and it only took about a mile for the AC to start cycling at 40*. Keep in mind the lower the fan speed, the faster the condenser cools and the quicker it reaches minimum temp.

When I leave work this evening, it should be ~100*f today. The car will have sat in the shade for about an hour (vent temp is usually 120*f). I'll a similar test to yours. What was your fan setting at idle? That should give you a good comparison of performance. I also still need to re-do the original book performance test at 1500rpm instead of idle. The increased rpm makes the high pressure higher, and the low pressure lower.

BTW: If you are idling on MAX-AC, the evaporator core CANNOT get cold enough to start cycling the system. And how cold it gets depends on all the external factors (sun, ambient temp, ambient humidity, etc). Mine would hit 42-43*f idling in the shade @ 97*f with 8% humidity during the charging process. The entire time it did not get all the way down to 40 and start cycling the system. This is with the two stock fans (used replacement condenser fan and aftermarket OE-style radiator fan motor).

For outside temp & humidity I used google. For vent temp I used a thermometer from Autozone:

James89DX

Mine is at speed setting 4. I guess I don't understand how that affects temperature, though.

For example, you said that having it on the highest fan setting doesn't allow the evaporator to get cold enough to cycle the system. But why would you want the system to cycle if you're sitting at idle and the car will struggle to even cool below 60? I don't understand why it would cycle if it never reached a low enough temperature to cause it to cycle off in the first place. And, I also don't understand why cycling would be beneficial temperature wise. When it cycles off it just gets hotter so what benefit would that have at idle? I guess I'm fundamentally misunderstanding something here.

Anyway, so, at idle with the fan speed on, say 2, my vent temps should be cooler than at idle on vent speed 4? That's kind of a catch-22. With the fan speed low, I'm insta-sweating because there's no airflow hardly and the air is also super hot. At least with the fan up high there's enough flow to keep me from sweating until I can get driving and get it to cool down.

And I haven't even done all those book performance tests because they seem pointless to me. Heck, for all I know mine may pass those with flying colors. But it's moot because when I'm sitting in traffic in direct sun in the noon heat in my office attire, I couldn't care less what the system will do in the shade revving up to 1500 rpm and with all the doors open, because that's not remotely a real world scenario. :p

94eg!

iTrader: (2)

The AC system is not bringing "cold" to you. The system works by removing heat from the cabin and radiating that heat out of the front condenser. The more heat you can radiate, the more cooling capacity you have. Conversely, the higher the fan speed in the cabin, the greater the thermal load your putting on the system.

This means a couple things:
- low blower speed = low thermal load = colder vent temps
- high blower speed = higher thermal load = hotter vent temps
- low condenser air flow = low thermal capacity = hotter vent temps
- high condenser air flow = high thermal capacity = colder vent temps

These are all variables. And as we all know, to gauge performance of any system we must eliminate variables. Therefore the book performance test outlnes very specific conditions:

- high load (high fan speed)
- low thermal capacity (sitting still)
- given compressor speed (1500rpm)
- no engine heat source (recirculate)
- no radiant heat source (sitting in shade)
- ambient intake temp (doors open)

This leaves you with only two variables for the chart that you must record separately:

- Ambient temp
- Ambient humidity

If your system passes the test and all specs are good, yet your still sweating ***** and unsatisfied, the only thing your left with is.......THE EF AC SYSTEM and/or YOUR GEOGRAPHIC LOCATION SUCKS! Get a different car or move (or both). lol j/k

Cycling: The system only cycles to keep the moisture build up on the evaporator from freezing and turning the entire thing into a non-functional block of ice. It can't transfer heat if it's frozen. The good thing about it cycling is that you KNOW your evap-core is getting as cold as it possibly can (Thermostat cycles off @ 36-33*f surface temp). There are still variables at this point though. You "could" have a bad thermostat switch. You could also have an evap-core with considerable blockage of air-flow passages. When I pulled my evap core out to replace all o-rings, I spent an entire evening picking 24-years of dust/fuzz buildup out of the incoming air fins. I would say it had at least 40% of the face completely plugged up. I guarantee that makes a measurable difference in it's ability to transfer heat from the warm intake air to the cold refrigerant. Greater area of air flow = slower air flow through core = increased heat transfer = colder vent temps. If you have a new core, I don't know what to tell you.