E30 + R134 = not impressed

[Schnitzer318is]

Well, I used to think that e30 systems were just sub par as well with 134a in them until I had my cars recharged at the shop I work at now. They have done so many r134a conversions it's ridiculous.

They recommended to not change a thing from the system... not even the drier. I was surprised... then they hooked up the refrig. machine to the car, knew exactly how much 134a to put in. Within a few minutes the vent temp was in the 20's in 90 degree weather at idle. I couldn't believe it.

My final question to the guys was why do most e30 ac systems blow sub par with 134a. The answer was that it was usually incorrect charge and the rest of the times usually clogged expansion valve or other component operating at less than full capacity.

[glucklich21]

So what about us 24v people? I'm still not sure how I'm going to set up mine. It needs to be cold in 5 o'clock traffic in Houston with 80% humidity and 95 degrees outside.

I was thinking, since I'm replacing everything, something like this:

E36 R134 compressor -> aftermarket condenser with Spal 14" mounted on front with a 2 volt resistor (10 volts with AC on) -> E23 (or something larger*) dryer -> E30 evaporator


*to combat high humidity, what this means is I'm looking for the largest possible, to remove the most moisture.

The E32/E34 dryer are the same unit. The 850i is a modified E34 unit. The E36 is tiny to say the least and is its own design. The E38/E39 unit and basically all BMW models after that generation are the same size, but different shape. The later style also brings along a different design. The E30 design, the hoses screw on. In everything basically post 80s BMW AC use a fitting like the compressor does. So to even try to run one of those would require a butt load of modifying hoses. Older would be better in this sense. An older Mercedes would also be a good alternative.

The evaporator we can't really change because of size restraints of the stock box, but the condenser we can to an extent.

The condenser for the E28 has two versions, the 528e version, and the TD, 535i, and M5 version. The latter being slightly larger and is the same size as the late model E23/E24. Early model E23/E24's are similar to the 528e.

That would work, but there's the slight problem of R-134 likes a parallel condenser which none of the stock 80's models are. So the aftermarket way has been kind to the E28 guys, so there's no reason we couldn't go that route.

They're using a 14x19.5 unit where their stock size is roughly 13x16. E30s radiator core support has an opening of roughly 23X14.5 (I don't have an E30 condenser handy at the moment to measure). I think a 12x21 would be a good size for us. This is leaving enough room for fittings/mounting and allows some room for air to go around to the radiator. Combine that with the Spal fan I mentioned earlier, it should keep it fairly cool.

But we shall see....

[g.ruff561]

I have a 92 MT2 vert that originally had 112. A/c worked like crap. Not from the 112 but from system faults. After finding several leaks and replacing hoses and fittings and tightening a/c belt, I decided to do 134. New reciever drier, vacumned the system and I now have 42 degree vent temp at idle and 36 at 80mph in 93 degree outside temp. My factory system now works great. Same expension valve, compressor, condensor and fan. I think the key is getting a good total vacumn of the system and getting the right mix of oil + refrigerant. Call Joe at Polar Bear A/c. He is in Ft. Lauderdale, Fl. His number is 954-463-6610. He sells new and rebuilt compressors. He does all his own work. Tell him Gary up in West Palm Beach referred you. Good Luck.

[Dominic49]

http://www.e30tech.com/forum/showthread.php?t=92614

[/thread]

[Dominic49]

p.s. OP if you dont want to do it yourself, bring it to AUTOCOOL in smyrna they do great work.

[TrentW]

Well, I used to think that e30 systems were just sub par as well with 134a in them until I had my cars recharged at the shop I work at now. They have done so many r134a conversions it's ridiculous.

They recommended to not change a thing from the system... not even the drier. I was surprised... then they hooked up the refrig. machine to the car, knew exactly how much 134a to put in. Within a few minutes the vent temp was in the 20's in 90 degree weather at idle. I couldn't believe it.

My final question to the guys was why do most e30 ac systems blow sub par with 134a. The answer was that it was usually incorrect charge and the rest of the times usually clogged expansion valve or other component operating at less than full capacity.

Interesting. I've seen others who have said that their R134a conversion cooled fine also, so it has to be that something wasn't done properly or that there was something else malfunctioning in the system. Curious about not changing the receiver/dryer though, and here's my question. I had my R12 recharged two seasons ago and it blew cold as ice all summer, but then last year there was green dye ALL OVER my compressor and it blew warm, so now I need to get a rebuilt unit. Isn't it true that whenever you open the system you need to replace the receiver/dryer?

Also, what's the best rebuilt compressor to buy?

[samiam3356]

p.s. OP if you dont want to do it yourself, bring it to AUTOCOOL in smyrna they do great work.

Autocool is awesome. We use them a good bit and they do good work at decent prices.

[g.ruff561]

Anybody had any experience with jumping the high speed relay so that the condenser fan runs high all the time? Any down side to this? I realize that the fan motor will have to be replaced sooner but several E30 owners here in Fla are doing this. Especially if you made the convert to 134. My a/c is real cold right now but I might try this in the future. More air over the coils = cooler air. Please advise......There is nothing more important to an E30 vert owner than cold a/c and a booming stereo system. Amen.....................G.

[HarryPotter]

I am currently switching over my fan to run on highspeed all the time. It's set to run on low speed all the time right now, but that isn't enough in a stand still. My a/c gets quite cold when driving but the lack luster performance at idle is frustrating.

I will try the high speed aux and see if that helps. If not, then I'll just

[badvibrations]

Just be happy the e30's cooling system is so low tech.
The modern BMW systems will completely stop blowing cold with a simple electrical problem, that may take a very long time to find. They can be extremely difficult to diagnose even for well seasoned techs.

[Van Westervelt]

So what did you guys use when replacing the expansion valve? All I have seen are r134a replacement units? I personally was planning on keeping it r12

[Wh33lhop]

Interesting. I've seen others who have said that their R134a conversion cooled fine also, so it has to be that something wasn't done properly or that there was something else malfunctioning in the system. Curious about not changing the receiver/dryer though, and here's my question. I had my R12 recharged two seasons ago and it blew cold as ice all summer, but then last year there was green dye ALL OVER my compressor and it blew warm, so now I need to get a rebuilt unit. Isn't it true that whenever you open the system you need to replace the receiver/dryer?

Also, what's the best rebuilt compressor to buy?

You are supposed to replace the dryer every time, but sometimes you can get away with not doing so. Basically you just don't want to contaminate the dryer with moisture, and cracking the system has the potential to do so. It is a $20 part, so it's relatively painless.

[Hey_You]

I work at a shop that specializes in Auto A/C (I'm not the one working on the systems all the time, but I am learning a shit load as I go) and if the vent temp is in the 20's...it's too cold. Yes, your A/C system can get too cold and cause problems. Vent temperatures should be about 35-45 degrees F (a tad colder if the ambient temperature is cold, or a little higher if it's hot as balls out) Moisture is easy to get out of the system if you have the right vacuum pump. At 30lb's of vacuum, water evaporates at 40 degrees, so leave your system on vacuum for 15-30 minutes, and that should take care of pretty much all moisture. Also note that contaminates that get into your system either from a failed compressor or whatever can stay there and cause problems later on. They get jammed into your condenser and drier and usually come free at a later point to foul your new compressor up. It's recommended that if you replace the compressor, to replace the condenser and drier at the same time to save from future headaches. Also note that anything over 2% air in your system can cause your A/C system to not perform correctly. It really does pay to take it to a shop after all your repairs you do yourself to have it professionally evacuated and recharged

[Schnitzer318is]

It really does pay to take it to a shop after all your repairs you do yourself to have it professionally evacuated and recharged

Informative post... and I definitely agree with the above 100%. That said, I enjoy my 30+/- degree air. LOL if it's a malfunction causing it... I'm leaving it broken. Today the wife and I had to turn the a/c down on more than one occasion from being too cold.

I should note now that we have seen some 100 degree days I find that at idle stuck in traffic I am seeing closer to 45 degree air at the vents.

I also should have noted before in the first post... I am running a volvo aux fan on high speed puller in front of the engine and an aftermarket 12" electric fan in front of the condenser as pusher. Perhaps the added airflow is helping me out.

[Ryann]

Lots of marginal/bad info in this thread!

OP: Is your compressor clutch short cycling? Are there bubbles in the sight glass on your drier? Both obvious signs of low charge. Also, are you certain your heater valve is shutting off all the way?