E39 LSx a/c thread

[modular93fox]

Didnt see a thread on the parts needed to DIY on the a/c side of the swap so here we are, a new thread. So what have you guys done to get the a/c connected... taken it to a shop and have them piece it together? if so post up how much that particular shop charged so others could get an idea on the cost. I am working up a parts list to use pieces that can be ordered online, mocked up, marked up and the taken to the a/c shop to get crimped. I would imagine this route would be the cheapest since the a/c shop doesnt have to "think" bout the how to get this to work.
One shop that had everything for the swap and closed its doors, Doc's Block. I did find another company that sells a/c fittings and adapters, but still cant find an exact match to the compressor manifold... the block has a raised face and both pilots are 5/8.
Anyway, I found various parts fittings, adapters and weld on parts.. just havent made an order yet. I need to cut my factory block in half and drill out the tube so I can do some mock up before the order.

Till then, theres a few people who have gotten a/c lines hooked up, post up the pictures if you have them and your solution.
clint

[James39]

You need all the GM ends for the GM equipment, and all the BMW ends for the BMW equipment.

Then braze on beadlock fittings to the BMW and GM ends to make the connection. The biggest problem I have is the aluminum pipe size on one end is always different than the size on the other end.

I can't find any #12 beadlock barbs that go to 5/8 pipe. Seems like #12 is 3/4", #8 is 1/2", etc... would be nice if there were options for the pipe end and hose end so you could mix and match.

They make what they call repair ferrules where you could probably put the bigger beadlock ferrule on a smaller aluminum pipe end, but I think my workaround will get the job done.

I ended up hacking braze on ends to fit the wrong size pipe. I know somebody out there knows how to do it properly, I just can't find them.

[modular93fox]

https://www.action-ac.com/AC-Part/35-B6605-A.html has the 12 hose to 5/8 hardline. I was building my a/c hose assembly to #8 and #10... the bmw compressor hoses and lines seem to be #10 and #12. The aftermarket compressor block that I found and might try uses #8 and #10... so either I can make it bigger hose and neck it down at the compressor, or just neck it down at the fitting thats gonna get brazed onto the BMW lines.
I have the discharge line on my truck a #12 fitting to a #10 hose.. ac works just fine..
clint

[James39]

[URL]
I have the discharge line on my truck a #12 fitting to a #10 hose.. ac works just fine..
clint

I was hoping it would too, although I'm sure there are reasons they designed the systems with various sizes. Those action AC fittings look good, they would have saved me some time, and reduced the amount of creative connections I used, but oh well

[modular93fox]

I seen your pictures and was like what did you use on..seemed to look stream line v.s. spliced. Once I order the fittings on my list, I will post up what is confirmed to work (on e39's) to eliminate the guesswork for the next guy that wants a/c.
clint

[modular93fox]

I had a few a/c fittings laying around, one happened to be a #8 tube to #8 beadlock. #8 is 1/2" and the BMW discharge line is .4XX the #8 would probably solder on no problem, but on a scrap piece of #8 tubing, that fitting was a real snug fit. So I thought about getting that splice fitting, cutting the end off and making a tool to press in to open it up. First go round involved a bolt, piece of wood and a sledge hammer. I opened the hole up, but the threads and hammer action left the inside less than desirable as metal shavings and compressor dont mix. So I took a scrap piece of that #8 tube to work and found a bolt that had a shoulder on it, was just the right size.. .46 or .47" and cut the threads off and put bolt in my dewalt drill and chucked it up and put it to the grinding wheel. This helped getting the tip even and smooth. I used a break line flairing tool to hold the tube in place, used a press to push this modified bolt and made my the tube expand like it was factory like! Took it home and test fitted it and sure enough, it was a damn perfect snug fit! I'l be honest, didnt think it was gonna fit... but damn! So that will take care of the "loose" discharge #8 fitting. I will do something similar to the suction line if the fitting is really too loose.
clint

[modular93fox]

Has anyone wires the gm PCM with the BMW high pressure switch. Tomorrow I will look at the e39 high psi switch and see what kind of info it says. If the schematic is like the gm.. Maybe give it a try and see what happens.
Clint

[James39]

Has anyone wires the gm PCM with the BMW high pressure switch. Tomorrow I will look at the e39 high psi switch and see what kind of info it says. If the schematic is like the gm.. Maybe give it a try and see what happens.
Clint

No, but after I already brazed in a new port I realized the switch I was using was different from the Camaro style fitting that seems popular. Wondering if a 2004 Cadillac CTS (which I'm pretty sure is what I am using) sensor might thread right into the port on the BMW line.

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Seems odd that different cars with the same engine would use different components...

[Quicksilver328i]

The F-body cars and the C5's use a sensor that (as far as I know) is exactly the same. It is a 0-5V sensor that provides an actual high-side pressure reading to the PCM. The BMW switch is a cut-off along the compressor signal wire. The two systems are not compatible.

The Chevy systems are actually quite easy to make work, but its worth mentioning a few of the differences - I plan to convert more of my system than most because in FL I want the AC to be as close to optimal as possible.

The AC system on the Chevy's run an orifice tube instead of an expansion valve. There are "mock" expansion valve orifice tubes sold as upgrades - but the orifice tube is much easier to service (engine bay instead of behind/under dash). Further, the chevy compressors are variable displacement, while the BMW's are fixed displacement. A variable displacement compressor with a moving valve may work - but I'm going to avoid finding out (CNCing a block to replace the expansion valve and putting the chevy orifice tube in).

The PCM controls all of the chevy functions, so you only need a signal to activate and deactivate the "AC request." On the BMW there is a lot of communication between the two modules, as a result I'm leaving the systems separate and wiring a simple switch for AC on/off (that will feed the chevy PCM) and using the BMW system unmodified for HVAC control (including the heater valve functions...).

The Chevy condenser looks bigger to me, but I haven't bought one yet or compared that closely. I anticipate comparing the two side by side and choosing the larger. The Chevy system has one more notable difference - the dryer is between the evaporator and the compressor. I don't know if its significant (it will catch debris if the compressor chunks - before it goes through the expansion valve or evaporator - as a pro BMW point) - but I'm expecting to only retain the BMW evaporator in the end, and chevy the rest of the system up to keep parts readily available (I mean, my autozone always has a 2000 camaro part....but a 1998 BMW 528i...)

[James39]

The F-body cars and the C5's use a sensor that (as far as I know) is exactly the same. It is a 0-5V sensor that provides an actual high-side pressure reading to the PCM. The BMW switch is a cut-off along the compressor signal wire. The two systems are not compatible.

The Chevy systems are actually quite easy to make work, but its worth mentioning a few of the differences - I plan to convert more of my system than most because in FL I want the AC to be as close to optimal as possible.

The AC system on the Chevy's run an orifice tube instead of an expansion valve. There are "mock" expansion valve orifice tubes sold as upgrades - but the orifice tube is much easier to service (engine bay instead of behind/under dash). Further, the chevy compressors are variable displacement, while the BMW's are fixed displacement. A variable displacement compressor with a moving valve may work - but I'm going to avoid finding out (CNCing a block to replace the expansion valve and putting the chevy orifice tube in).

The PCM controls all of the chevy functions, so you only need a signal to activate and deactivate the "AC request." On the BMW there is a lot of communication between the two modules, as a result I'm leaving the systems separate and wiring a simple switch for AC on/off (that will feed the chevy PCM) and using the BMW system unmodified for HVAC control (including the heater valve functions...).

The Chevy condenser looks bigger to me, but I haven't bought one yet or compared that closely. I anticipate comparing the two side by side and choosing the larger. The Chevy system has one more notable difference - the dryer is between the evaporator and the compressor. I don't know if its significant (it will catch debris if the compressor chunks - before it goes through the expansion valve or evaporator - as a pro BMW point) - but I'm expecting to only retain the BMW evaporator in the end, and chevy the rest of the system up to keep parts readily available (I mean, my autozone always has a 2000 camaro part....but a 1998 BMW 528i...)

Accumulators go on the low pressure side, and keep liquid from getting into the compressor. Receiver driers go on the high pressure side, and basically store the liquid that's metered by the expansion valve. Orifice tube systems flow a constant rate of refrigerant through the evaporator, TXV / receiver drier systems rely on the TXV to meter the liquid going into the evaporator.

The TXV system seems like it would be a little more forgiving in terms of system design, over charging problems, etc. My AC seems to be working very well with a C6 vette compressor, C5 condenser, and the rest BMW. Every time I've looked at the vent temps, they are generally more than 40 degrees less than ambient temps, and it doesn't need to work to hard when I set it to 65 degrees on the IHKA.

I wired my 12v+ off the AC led button in the IHKA. Press snowflake button, AC is activated. Climate control seems to work as intended this way.

[modular93fox]

I have placed a seocnd order of fitings and out of all of the fittings ordered, #10 and #8 inside fit weld on barb fits great. With the OE suction line removed and the furrel cut of and then used a tubing cutter right htere at the nurled part of the tube. There was no defect with the end of the pipe, but I was impatient and used a drill bit a hair larger than the standard 1/2" to open up the ID of the tube (since I didnt have a 1/2" on hand) and the fitting was a little loose. So with the tubing cutter kind of deforms the inside a slight amount due to the pressure of the cutting wheel .. its normal to debur the inside, but the # 10 fitting fits like a champ - ready to get brazed on.
The OE line at the condenser was preparied the same time and the # 8 fitting wouldnt fit inside. A 5/16 bit was used by hand to open up the line and the #8 fitting fits in there snugly and is ready to be soldered:


zewz.jpg
pic shows the suction line with the slightly larger than 1/2 bit used to open line up. didnt take a picture after cutting off the nurled portion.

once the a/c lines have been crimped, I will update with what worked for me so the next person wont order a ton of fittings like i did.
clint

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Any update?

[modular93fox]

Any update?

yep, as of today I have most of the fittings brazed up and ready to for mockup... just lacking the a/c compressor fittings that will be done tomarrow. He wanted to tig weld the adapters. over all pleased with the results thus far.

I have a parts list of the fittings used but one i cant find.. its a 90º barbed on both ends that uses ferrels on both ends.. but cant find one in the catalog. I brought him all the fittings I had, and he recommended using #12 on the suction side when I brought him # 10 fittings and all was setup for #10.
So he brazed on a #12 outside fit barb to the evap line going to the compressor.. thats going to about a foot or so of hose, then there is a 90º with a low side charge port brazed on to it, and then a small 4" or so piece of hose to the compressor adapter (modified) - picture will show the mod.
on the discharge side, its the a/c adatper that was modified with a brazed on #8 90º fitting to #8 hose to a #8 braze on outside fit fitting (on the BMW hardline). I also had the high pressure switch adapter brazed onto the bmw hard line aswell. Just need to pickup the a/c compressor adatpers tomarrow, do a final fit and mark the hoses for crimping and that the end of the a/c hose chaper. Need to add wiring for the a/c pressure switch and interior a/c on signal to PCM.
clint

[modular93fox]

[modular93fox]

Hoses mocked up, lined up and marked an ready for crimping

[modular93fox]

well somethings incorrect... my sensor could be faulty or the 3 wires I just wired up are incorrect.... but the a/c does not come on when the a/c request 12v is applied. I can use efilive to activate the compressor which means the PCM can turn the compressor on so that relay circuit is correct.

Can the high pressure switch/sensor not work if installed on the liquid line? i didnt even think of that as a problem when i had the a/c shop solder it together.. never seen on on the liquid line... didnt even think about it being a liquid line untill i already had the fitting soldered on.

other thing is since im not using the bmw system to operate it and the a/c will be on all the time once activate since the compressor gets cut off with the ihka reading from the evap temp sensor.... does anyone have any evap freezing problems?

just tired of sweating in the 5 after buying a new a/c delco compressor and the system charged and ready to cool once the electronic is squared... not sure what the problem is..

maybe i will try and the BMW high pressure switch and tap into it and see if the system operates then.. BMW schematic calls it a switch, the gm calls it a sensor... think its both a switch... think I have the conversion schematic from BMW to GM pressure switch pins thought out.. atleast visually it looks correct.

fresh eyes is the ticket here and anyone have em'

[Quicksilver328i]

The BMW is a switch, the GM is a sensor. ***** I have tested the BMW switch for continuity/resistance and verified it as a switch, I have not tested the GM sensor but am basing it off technical literature from GM.

The sensor provides a reading that needs to be between certain pressure ranges for the AC compressor to engage. I would assume that it should at least momentarily engage your compressor wherever it is located, even if only for a couple seconds as - with the system off - all locations in the system will have the same pressure.

If your compressor engages for a moment and then shuts off its possibly just that the sensor is on the wrong side of the orifice tube.

Something I had concern with was how the expansion valve would interact with a variable displacement compressor.

[modular93fox]

how much refrigerant have you guys used when charging the system. I charged my system up to 1.65 which is what the e39 system says to run... anyone know the a/c pressure of a factory ls1 system run?

[James39]

well somethings incorrect... my sensor could be faulty or the 3 wires I just wired up are incorrect.... but the a/c does not come on when the a/c request 12v is applied. I can use efilive to activate the compressor which means the PCM can turn the compressor on so that relay circuit is correct.

Can the high pressure switch/sensor not work if installed on the liquid line? i didnt even think of that as a problem when i had the a/c shop solder it together.. never seen on on the liquid line... didnt even think about it being a liquid line untill i already had the fitting soldered on.

other thing is since im not using the bmw system to operate it and the a/c will be on all the time once activate since the compressor gets cut off with the ihka reading from the evap temp sensor.... does anyone have any evap freezing problems?

just tired of sweating in the 5 after buying a new a/c delco compressor and the system charged and ready to cool once the electronic is squared... not sure what the problem is..

maybe i will try and the BMW high pressure switch and tap into it and see if the system operates then.. BMW schematic calls it a switch, the gm calls it a sensor... think its both a switch... think I have the conversion schematic from BMW to GM pressure switch pins thought out.. atleast visually it looks correct.

fresh eyes is the ticket here and anyone have em'

You can log the AC request state (on/off) and the high pressure switch to see what they say. That would be the first place to look.

[rao]

I have never had the evaporator ice up and I have run a full tank of gas through the car with the ac on in one shot.

The service manual for the donor car will have an AC performance chart, set up the manifold gauges vacuum the system and then fill it until it is in the sweet spot on the chart. For my system it was a lot less refrigerant than the BMW system used.

[modular93fox]

Doh, the cigarette adapter I had used had a blown fuse... After wire testing the sensor and all that nonsense. Ac is cold, center vent at cruise is 40... I will check on the ac pressures later on in the week.
I also will check the voltage displayed in efi live for the ac pressure sensor and inpa for the BMW one.. At ambient temperature ac off they were both read 1.3v... Later in the week I'll see if I can have efi and inpa open at the same time and read each values both at the same time and see if they correlate to one another... maybe no need to braze in that gm sensor firing... just a simple rewire of the BMW sensor connector...

[Schitzo]

Clint, here are some pressure vs. volt numbers for various A/C pressure sensors. The LS1 F-body sensor is MT1339 and the E39 sensor is MT1205. Here is a fun fact, the GM sensor uses a metric thread and the BMW a standard inch thread

[modular93fox]

the BMW a standard inch thread

Sounds about like BMW..

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It's getting mighty warm around here...