E30 + R134 = not impressed

[LJ851]

Its starting to warm up here in Atlanta and i would like to have a car with working A/C this summer. When the car was purchased it had a couple small leaks which were repaired last year. It had already been converted to R134 by the original owner . The expansion valve was deemed sluggish so a new one was installed along with a new receiver dryer. The A/C is not very effective in its current state, It never blows very cold and with the car stopped or going slow the air is barely cool. It would not be possible the start the car and turn on the A/C to cool the car before driving. The aux. fan is functional. What is holding my system back?

[bmwstephen]

low refrigerant levels?

[trackjunkie21]

If you want cool A/C, you have the wrong car, it only works well when driving at higher speeds. I just got rid of mine.

[redsubdivisions]

the fact that system was designed for R-12 efficiency in mind. I didn't expect a brand new cooling system when I did mine, but it definitely beats having no A/C. I read that you can always get a bigger condenser and that might help.

[bmwstephen]

definitely check for leaks again OP by a professional too. I was in the same situation as you. my first retrofit with r134 didnt go as plan. as it turns there was a small leak discovered via UV light, when I installed my new evaporator. patched that up and it still wasn't working... turns out the initial HVAC guy didnt load the proper oil to refrigerant level ratio. Now I have ice cold AC that is no differ than r12

[bmwstephen]

the fact that system was designed for R-12 efficiency in mind. I didn't expect a brand new cooling system when I did mine, but it definitely beats having no A/C. I read that you can always get a bigger condenser and that might help.

not without modification, I recommend a bigger aux fan before that.

[CorvallisBMW]

The entire e30 system is undersized for r134a because it was designed to work with r12. The compressor, condensor, evaporator and EV are all designed to work with r12 which has a lower vapor pressure (more efficient) and carries more energy (btu/lb or J/kg). Yes you can put r134a in an e30 and it will work, sort of. The biggest upgrade you could make would be an oversized condensor from, say, an e32 or something. That will help with the issue of higher vapor pressure and ensure that more of the superheated gas coming out of the compressor is being turned in to subcooled liquid before hitting the R/D. A higher-flow aftermarket aux fan (Spal for instance) would also help, but only so much.

[woodisgood]

What about a bigger compressor? I have been wondering about this lately myself....also, now that all the leaks are cured in my system, what about going back to r12?

[LJ851]

I dont have A/C equipment (one of the few tools i dont own) so all the work has been done by a tech with many years of experience on both german cars and A/C systems. I trust his work and im not trying to hang sides of beef in the car, but i am pretty sure it can be better than what it is now.

[StereoInstaller1]

There is a huge thread somewhere regarding "Parallel Flow" condensers, there is a bunch of info on that particular upgrade.

My plan was all about DuraCool, until I read this: http://www.epa.gov/ozone/snap/refrigerants/hc-12a.html

[StereoInstaller1]

If you do the beef thing, get some pics, OK?

[bmwstephen]

What about a bigger compressor? I have been wondering about this lately myself....also, now that all the leaks are cured in my system, what about going back to r12?

if you replaced your expansion valve, chances are you can't. newer expansion valves are designed for r134a and not backwards compatible

[CorvallisBMW]

What about a bigger compressor? I have been wondering about this lately myself....also, now that all the leaks are cured in my system, what about going back to r12?

Without enlarging the rest of the system components (especially the condensor) you could end up blowing up the system due to too-high pressure. You'll also increase the risk of leaks as high side pressure will be much higher, as well as risk running the low-side in a vacuum (air infiltration=efficiency loss), freezing up the expansion valve and even slugging the compressor.

[mikeedler]

I have never been in an e30 with working AC, but I will put out there that BMW AC is nothing like US car AC by any standards. I have always thought my wifes E46 since new sucked compared to my old Chevy truck. have it charged and deal with it I guess....

[Kershaw]

^ this.