328 A/C Compressor

Just empty your compressor first then you can start to use R13.......Why stay with R12?

 

get a Sanden 508 rotary compressor.

JFrazar has been installing them on 308's, 328's, Mondials and as of last week, a local BB512i.

They work great!

Pic of mine getting installed in March during my major:
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Guess you dont live here in the tropics, eh?

 

Several options:
The stock a/c works OK with the original compressor and R12 if everything is in good order.
Maybe you could just put it all back and charge it...or maybe not.

It would be nice to know why your old system quit (compressor failure vs. major leaks vs. slow leak, over years, of R12).

R12 is pricey and destroys the ozone: you don't want to put it in a system that leaks.

If you convert to r134A you will lose performance unless you upgrade to a larger condenser, which probably means putting one in front of the radiator.

The Sanden compressor is better in some ways, but the York is "original" for what that's worth, and entirely adequate.

 

The Sanden is smoother and takes less power to run; the York can move more refrigerant. If the original compressor was missing or not fixable, I would rather have the Sanden. But if the York is OK, replacing it with a Sanden will not improve cooling.

 

You have this backwards; the stock York is a R206R, with the 06 indicating 6 in^3 displacement (the smallest of the York compressors), which is 98 cm^3. The Sanden typically used for retrofit is the SD7H15 model 4627, which displaces 154.7 cc's. The Sanden is slightly more efficient and definitely smoother in operation thanks to the 7 stage compression versus the two of the York. The Sanden reaches two tons of cooling capacity (the rating of the externally equalized TXV valve used in the later 308 and 328 A/C systems) at just under 3000 shaft RPM; the York only reaches this capacity at over 4500 RPM.

Edit, a note on R-12 vs R-124a: the TXV valve is rated 2 tons with R-12; it's R-134a rating is lower (but I'm too lazy to calculate the de-rated value). The Sanden cooling capacity rating is based on R-134a (just over 1 ton at 1500 RPM, 2 tons at 3000 RPM); running R-12 in the Sanden will yield larger cooling capacity at the same RPM, or a lower RPM required for a given capacity. (But be sure to check on the oil compatability!) The OEM York compressor running R-12 reaches 2 tons of capacity at over 4500 RPM; switching the OEM York to R-134a requires more RPM to reach 2 tons of capacity, but I'm too lazy to calculate it right now. Then again, the TXV doesn't have a full 2 ton rated capacity when using R-134a.

-frank

 

First time I have ever heard that claim. But if you are sure they are correct (and they differ from all the specs I have read prior to your post ) then perhaps the Sanden does not suffer in comparison capacity-wise. But the fact remains that the York has adequately cooled far larger cars than these 3x8s...

 

Sanden 509 also works on 3x8's according to JFrazar.

 

Absolutely sure about the York; I'm very familiar with the York compressors as I've added them as air compressors to several off-road trucks (a big Bronco and an IH S-2, and a parade of Jeeps). These small Yorks are actually fairly uncommon; the large American sedans used the 10 in^3 displacement Yorks (which are also much better as on-board air compressors).

Someone mentioned the SD508 in this thread; that unit is a 5 stage compressor designed for R-12 and displaces 138cc. I don't see an SD509 on my list, but the SD709 (7 stages) is designed for R-12 and displaces 155cc: this is just about the largest capacity compressor that you could justify stuffing into the 3x8 A/C system (it's essentially an SD7H15 designed for R-12: so if you are sticking with R-12, the SD709 is a much better choice than the SD7H15).

In experimenting with and analyzing the 3x8 A/C system, I think the primary issue is performance at/near idle, at low engine RPM. At highway speeds, with the vents set correctly and the electrical system working right, I've had great performance from the stock system - and the performance is backed by the theory based on the component sizes.

But idling in traffic on a 100 degree high humidity day is a different story! Some people may feel the stock system running R-12 is acceptable, but capacity at idle is really minimal at best and not sufficient for really hot/humid days. Switch the system to R-134a and idle performance will suffer greatly, generally putting the system into unacceptable territory.

The best solution to the performance at idle problem really is to upsize the compressor: definitely upsize if you are switching to R-134a, but you may want to upsize even if you are sticking with R-12. R-134a conversions are constrained to less than 2 tons of capacity if you stick with the OEM TXV valve, as it can't flow enough refrigerant even if the compressor is capable of delivering it - but this won't affect performance at/near idle (as no compressor is capable of delivering 2 tons of capacity at idle). Unfortunately I have not been able to find a drop-in replacement TXV that is sized for 2 tons on R-134a.

Of course, another solution would be the hack that some American cars have used: kick the idle higher when the A/C is on. This could be readily added to the K-jet system (I think), but it's quite the bad hack, IMHO, as really messes with drivability....

-frank

 

Is there a Sanden unit that is good for R134 that fits like the 508?

 

It also turns out that we neeed the proper thermal expansion valve for R134

 

I would sum up the compressor alternates like this:
- If you want max capacity and are willing to stick with R-12, go with the Sanden SD709
- If you want to switch to R-134a, go with the SD7H15 (which fits like the SD508, if you compare similar models of each)
- If you must have an OEM look for the compressor and want increased capacity and/or are switching to R-134a, find a York R210R (good luck with that) [I believe it will fit, but have never looked at this option with any seriousness]

If you have the externally equalized TXV used on the later systems (late QV onwards), then it will work with R-134a, but will have two issues: it will not flow enough refrigerant to deliver 2 tons of cooling capacity, and it will run at a lower superheat. The reduction in capacity is a significant negative issue, but the lower superheat is actually a net positive: a lower superheat means more effective use of the whole length of the evaporator, which is a good thing. In most systems, a lower superheat is undesirable as it increases the liklihood of the compressor drawing in liquid (a killer for compressors), but as the 308 has such a huge run of hose from the evaporator back to the compressor, and as this hose has virtually zero insulation from the hot discharge hose, there's effectively no possibility of the compressor drawing in any liquid even with zero or negative superheat at the evaporator refrigerant exit. In fact, you can get a little better performance out of the stock system if you move the sensing bulb for the TXV as far as possible downstream, at/on the fitting to the hose (but be sure to insulate the whole connection/bulb well); this causes the TXV to run the evaporator with a bit more liquid, resulting in more complete use of the whole surface.

Note that on R-134a, for a given low side pressure, the evaporator will run warmer than on R-12; thus, balancing compressor delivery volume and net charge of the system is very important on R-134a: over filling the system and/or a compressor that can't keep up with the load will lead to a huge drop in performance as the evaporator will run too warm (low side pressure too high).

One last note: if you are re-using the original TXV after a refurb of the system and/or a switch to R-134a, BE SURE TO FLUSH THE TXV VERY WELL! These valves are notorious for getting clogged with debris and are a favorite place for incompatible oils to lurk. It really is best to replace these, though.

I have some other ways to improve the performance of the system, but I'm still refining them....

-frank

 

Thank you for this great information. They sell conversion kits that advertize a flush with oil thet has additives to neutralize the bad oil. Doeas this work? And, do you have any part numbers for suggested TXV to do the conversion to R134a? Als, what does downstream mean for the sensing bulb in your disciption?

 

Damn Frank, I wish you weren't across the country.

 

We use a Kia valve, its the same thing. Joe has the numbers.

 

I am a bit of a newbie, who is Joe? Kia year and model? Thanks

 

Let me clear up some of the numbers and names mike is using.

Sanden 508 Compressor with a CB head - The head is the section on the back of the compressor that you can change to match up to your lines. The CB head uses the stock 308 fill ports and matches the connections on the old york compressor. As another note you can also use a sanden 507 compressor same design as a 508 just a shorter body.

The exp valve is very common and any local parts store can match up. Mazda 323 is one that comes to mind. The driers can kick your but a little. I know that the drier we used on the 512 crossed over to a late 90's dodge van you just remove the installed bracked and it is a perfect match.

Condensor, Yes the best ac we ever got from a 308 was a 77 B that had a bad condensor. We made mount tabs and installed a modern 134a condensor inplace of the original, that car trully would freeze you out.

Joe Frazar

 

Thank you. I am gathering the parts to take to my A/C professional to install. Interesting about the different fitting end. Does the longer 508 still fit even though it's longer? Sorry about all the questions but with each answer it seems another variable appears.

 

sorry for the confusion.

 

"I have some other ways to improve the performance of the system, but I'm still refining them...."

You sound as though you have a lot of knowledge re all this which is great. I was not aware that the York compressor in the 3x8 is not the same model York that was in large US cars. However, I would ask that you post some sort of actual data re these improvements. IOW, what is the actual change in the difference between condenser ambient air and cabin air in a 3x8 with these "improvements."

I have been learning a lot about ac in cars because shops have twice degraded the performance of my 328's ac. So I decided to become my own tech. I do all my own ac work now and I have managed to get my 328 to produce 45 degree temp drops at cruise without changing any oem parts (other than new exp valve/drier - which is really just routine maint). The limit as far as I can see, is the limited air volume produced by the oem evaparator. Of course, if the oem evap could move more air, then there might be a subsequent limit on the rest of the system.

 

The A/C performance varies greatly between idle and ~3k RPM cruise. And cruising along at 4k+ RPM delivers even better A/C performance.

If you move more air through the evaporator at idle, you won't deliver much more cooling; instead you need to improve the heat absorbtion capacity of the evaporator / system.

Lastly, mentioning temps is almost pointless without also mentioning humidity: hot humid air improves the efficiency of the condensor slightly, but condensing humidity out of the air at the evaporator takes an enormous amount of heat capacity, more than making up for the small improvement in condenser efficiency.

-frank

 

I understand the importance of humidity, etc.

I guess what I have become quite adamant about is some sort of data as opposed to, "I did X and my ac works great." I have found that one of the biggest issues is that we all have different comfort levels and that one person might be comfortable with the car cabin being at nearly 80 (like my wife) while another (like me) isn't comfortable unless it's down around 70.

So the opinion of whether an ac works well or not is largely an opinion of the person in the car at the time. But without some sort of data there is no way to really determine if a change will actually make a difference and, even if it does, is it worth bothering with.

I have posted here before that my 328 will now produce considerably lower evap temps under the exact same temp/humidity conditions compared to my wife's MB - by nearly 10 degrees. (It never did that when serviced by two different Ferrari "specialist" shops.) But because her car probably pushes out 4-5 times the air volume and directs it better, the cabin can be made much cooler.

There are a ton of posts/threads on this subject - some folks completely revised the entire system. But I'm not sure anyone has so far come up with anything that made a really major improvement in the actual cabin cooling - at least on the 328 which has a different condenser setup than the 308.

 

Mike,

Does your 328 have the exact same evaporator as (my) 308? R U running 12 or 134?

 

I don't know if the evaporator is the same on the 328/08 but I am running the oem 328 evap. I'm using Duracool for refrigerant - it has almost identical cooling characteristics to R12; Duracool is a tiny bit more efficient by specs but can't imagine there would be any noticeable difference between the two. I'm quite pleased with Duracool though it's totally a DIY thing since I don't believe ac shops will deal with anything but 134 and R12. Heck, some won't deal with R12 any more.