E30 + R134 = not impressed

[LJ851]

There are people with E30s that have acceptable A/C systems and that is all i would like. Im not expecting meat locker conditions, My car does not cool when stationary and that has to be fixable cause it cools somewhat at speed. The tech that did the A/C work recommended a larger parallel flow condenser as an area that could make an improvement. The car has 200k on it, would a new compressor help ? Is it wise to add a larger more efficient cond. without changing other components like the evap?

[expressfish]

my vert is converted R134 also and it wasn't blowing as cold as it should at idle either. I busted out the gauges and found the refrigerant low. I topped it off with a full can at about 30psi low side and 250 high and it helped out alot. On that note I dont think any r134 system is going to blow too cold at idle, they seem to like 1800rpms and up.

[StereoInstaller1]

As a side note to all of this: I worked on a TON of E30s straight off the showroom floor, often before the new owner saw it.

The A/C was insanely cold, even at idle, even on a 100 degree day.

These cars were near $30K back when that was a fairly impressive annual income.

[bmwstephen]

As a side note to all of this: I worked on a TON of E30s straight off the showroom floor, often before the new owner saw it.

The A/C was insanely cold, even at idle, even on a 100 degree day.

These cars were near $30K back when that was a fairly impressive annual income.

so adjusted for inflation, we can safely say that the materials used on modern bimmers to maintain $30,000 in present day dollars is pretty crappy

[bimmerteck]

My e30s A/C puts out 34 degree air and cools my 'vert cold enough I often can't stand to leave it on any longer at times. e30s also convert to 134a just fine if the tech is good with german car conversions you shouldn't have any problem getting the car to cool well.

I change the dryer, the aux fan resistor out to increase aux fan's low speed, and draw a long vacuum before charging. if the vent's don't go sub 40 degrees inside 5min. on fan speed 2 in ac with recirculation on it's time to start finding the failed components.

[hoveringuy]

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?

Mine was converted to r134 and sucked, too. In D.C., no less.

I switched to Duracool and noticed a nice drop in vent temps. No shop will work on it with Duracool because it will contaminate their equipment but the stuff works.

[nrubenstein]

R134a can give you adequate performance. I'm now running HC-12a which is much even better.

The key to getting good r134a performance is that you absolutely must fill by weight. If you're slightly low, or more than two ounces high, performance will suck ass. And my observation was that the gauges read pretty much the same thing across a wide array of fill levels, so they don't really tell you a lot. Also, you want to bypass the aux fan resistor so it always runs on high.

[LJ851]

Thanks for the replies guys. Does anyone have actual experience with the installation of a larger, modern condenser and a real fan ?

[TwoJ's]

It wouldn't be the easiest thing to do with the on/off clutch that is on the pulley, but overdriving the compressor would improve the functionality. I thought that it was only my AC that worked shitty at low RPM, but hearing that that is very common makes me think that it's inherent in the design.

[CorvallisBMW]

R134a can give you adequate performance. I'm now running HC-12a which is much even better.

The key to getting good r134a performance is that you absolutely must fill by weight. If you're slightly low, or more than two ounces high, performance will suck ass. And my observation was that the gauges read pretty much the same thing across a wide array of fill levels, so they don't really tell you a lot. Also, you want to bypass the aux fan resistor so it always runs on high.

r134a has a different density than r12 along with other different characteristics. If the system was designed for 22oz of r12 (for example), then shouldn't it require a slightly larger amount of r134a? That's my understanding. Also, unless you've had the system evacuated by vacuum there is bound to be some leftover oil and water in the drier and other low spots. Keep that in mind.

[bimmerteck]

r134a has a different density than r12 along with other different characteristics. If the system was designed for 22oz of r12 (for example), then shouldn't it require a slightly larger amount of r134a? That's my understanding. Also, unless you've had the system evacuated by vacuum there is bound to be some leftover oil and water in the drier and other low spots. Keep that in mind.

Yes they do have different density, it takes less r134a to equal r12. I usually multiply by .8 to get my base charge. Systems should always be drawn down by vacuum to be able to accurately measure the charge.

[325ix]

Mine is not that great either. It doesn't bother me though. I just use the windows! Last summer when I was back visiting friends and family in Georgia I never used a/c once, we jsut opened the windows and if it got extra bad we would turn on the fan.

[BeirBrennerE30]

My a/c sucks too. Subscribed to the thread to see if anyone comes up with anything. I just thought it was because I had a hodgepodge of a/c components, e46 compressor, custom lines, e30 everything else converted to 134a.

[nrubenstein]

Yes they do have different density, it takes less r134a to equal r12. I usually multiply by .8 to get my base charge. Systems should always be drawn down by vacuum to be able to accurately measure the charge.

IIRC, the E30 takes 27.5 ounces of R134a. You can be a couple ounces over that. I fill to 29.5 to account for hose losses.

That said, Duracool/ES-12a/HC-12a works a lot better. My vent temps have been pegged at 32 degrees since I switched (no matter what fan speed - which suggests headroom). It hasn't been hot here yet, but I'm really looking forward to seeing how the system does then. Ironically, I found that you have to fill with HC-12a by pressure. I tried by weight and was WAY high on pressure.

[badvibrations]

Another thing to keep in mind is that r12 is much more efficient than r134a. And really just a better refrigerant(IMO). If you compare condensers from r12 designed systems and r134a designed systems, you will notice a big difference in size. r12 being more efficient, require a much smaller condenser than r134a. So when converting to r134a, the current condenser may not have the surface area to cool enough of the refer to cool your vent temperature to a more desireable degree.