Operation: I want Air Conditioning in my LS!
 

Found this little gem on Craigslist for $260.00! Complete car with a spun bearing.
https://www.v8miata.net/attachment.p...ine=1440972686

Started to gut it and harvest the AC system
https://www.v8miata.net/attachment.p...ine=1440972686

My LS car sure has a rats nest to deal with!
https://www.v8miata.net/attachment.p...ine=1440972686

Here is engine bay before:
https://www.v8miata.net/attachment.p...ine=1440972686

I'll post more as I deal with the wiring.........

Its nice to have a car side by side to compare things to. I'm working on getting the harness all back on the same mounts and along the same path. New components dropped in nice after some wire redirection. Need to figure out best mounting for computer and fuses now. Looks like passenger foot well will be best option.
https://www.v8miata.net/attachment.p...ine=1440975927

Used factory Miata lines and cleaned up engine bay. Had to bend them around headers a bit.
https://www.v8miata.net/attachment.p...ine=1441064683
Attached condenser to radiator. I hope those puller fans draw some serious air.
https://www.v8miata.net/attachment.p...ine=1441064683

I was surprised to see that the GTO crank pulley uses the same 4 rib pulley that the Miata compressor uses. I tried to come up with a way to get it to work, but since it is on the opposite side of the motor, fittings were not working well. Gonna hook up a GTO compressor and find a shop that can finalize the connections for me.

Just bought this little gem off e-bay. Plugs into the GTO LS2 ac compressor and turns the fittings 90 degrees and coverts them to standard AC threaded fittings. This should make fabricating lines to attach the Miata hard lines to the compressor easy (hopefully). Next steps: double check fitment of compressor and figure out electrical. I figure all I need is to connect power button on AC controller to the compressor? I believe in the 1996 model, the AC power was connected to the computer which in turn sent a signal to the compressor. All other controls are direct connected to the components (fan speed, temp control, and duct select).

https://www.v8miata.net/attachment.p...ine=1441140131

Loving this thread! I'd really like to get mine working too but can't get hoses made anywhere around here. Big surprise in a town of 1200 in the tundra.

On the wiring you have to put a relay in it because Mazda uses ground to close the AC relay and GM uses hot. So the button on the dash closes the relay using the ground side to switch it and sends B+ to the computer telling it you want AC. The other way you can do it is to tap into the signal from the little blue AC light in the dash and just jumper that off to the ECM. You have to take the controls apart a little but that's the way Shannon did his and it's still working. I used the relay method and but with no hoses have no idea if it works.

Side note a lot of swaps just bypass the computer and let it be manual control via the Mazda wiring that kicks on the fans and compressor.

So how would you feel about having your AC shop whip up a 2nd set of hoses that match yours and drop them in the mail to me?

Unfortunately, compressor adapter won't be here till after weekend so I won't be able to get lines done then. I will do wiring though. Think I will direct wire button to compressor. Push button, send power to compressor. If I need a relay in there, I will ad it. If I figure out AC line issue, I'll let you know.

You still have to have a relay in there because you don't want that little blue light circuit powering the compressor but Mazda already has one on the pass shock tower by the overflow bottle. It's in a bracket next to the 2nd fan relay.

The stock F body compressor manifold worked fine in mine but it is tight in there. LS2 could be different though.

No hurry for me they would not go in till next year anyway. I just thought if you wouldn't mind it would be a handy way to get them made and know they will work. Without driving to Omaha or Kansas City that is. I should have had Shannon do it when he did his but at the time it didn't dawn on me that custom AC lines would be as hard to get made here as snow plows are in Houston!

holy cheap ....for a complete car too !!??
u can get your $$ back in like 1 hr

i am here for the AC, following

Right! Keeping the donor around for a bit as I rob parts off of it to bring the LS car back to how it should be. I find I'm missing small brackets, fasteners, etc. This makes it real easy to make things right. PO changed out the 1996 dash with a 1990 dash to make it look clean with no airbag lines. Found he was missing a few fasteners. Not anymore! Should have wiring done this weekend and Ill let everyone know what my compressor connection plan ends up being and how it works out and cost of custom lines.

I think the advantage to having the engine computer in the mix is that it knows the A/C has been turned on and compensates for the additional load the compressor puts on the engine. When I cold start the engine for example with the A/C already on the EEC actually delays the clutch engagement a few seconds. It also turns off the A/C clutch at wide open throttle, etc. The EEC "manages" the clutch engagement based on the environment so to speak.

I've been researching using the GTO LS2 PCM, but the pinout is confusing. I found on connector 3 pin 51 sends signal to compressor relay, but can not find out what connector and pin receives the signal from HVAC controls (push the blue button). Also, I will not be running high and low psi switches, so I need to figure out how to send those a signal to let the compressor turn on. More to follow when I get a few beers in me and study the papers all over the shop! LOL. It will all make sense.

Ok, after a couple hours research, found out LS1 and LS2 PCMs are different. My LS2 gets AC request signal through a BCM, which I don't use in this swap. So I'm gonna use a relay to send signal direct to compressor from Miata HVAC controls. Done

So that's why guys by pass the computer for it! Makes sense to me.

I'm tuned into this thread as well. When I can find the time this Fall, I plan to take the same path as Gunpilot. LOVE the white NA purchase. You, sir, are certifiable Miata aholic now. Great buy.

Once you have a length let me know. The fittings you'll have are not the same as a Ford compressor which means I could have a custom set of lines made for you. I'll have them done at cost so I can make up a kit for the LS using that adapter.

-Jason

Jason- for sure. The adapter creates a 3/4-16 and 7/8-14 threaded nipple. Im hoping I can somehow use a mix of the few lines laying around to work, but most likely will need custom lines.

It's strange the LS1 PCM has an AC request signal in the wiring diagram, but LS2 does not. It was frustrating me until I came across an article about the LS2 BCM (body control module) that integrates with the PCM on a CAN bus. For AC, the signal from the car control goes to the BCM first, then to the PCMwhich sends out a compressor on signal. Without BCM, you can't trigger the compressor on signal. Only option is to use a relay to send 12v to compressor. From swaps I read about, a manual tranny car has no issues with change in engine load. Auto cars do have issues. Anyway, only way to know is DO IT!

Originally I would just wire up the AC systems as "dumb" systems where I would just jump the wire that came from the HVAC controls to the original ECU to the wire that left the original ECU and ran to the rest of the AC system. I would then just swap out the Miata AC compressor plug with a Ford one and be done with it. On a 1990-93 car the stock Fan relay was tripped by the thermo switch or the AC system so they actually needed no further mods to work. On a 1994+ car I had to jump an additional wire at the old ECU plug to trip the AC fan relay.
While this caused a slight drop in RPMs it was not enough to stall the car and was not that big of a deal. If it did become a problem I planned to wire a canister purge valve into the compressor trigger wire and then plumb it to the manifold to create a controlled vacuum leak whenever the AC compressor cycled on. I experimented with this and found that a standard vacuum hose diameter leak was just enough to bump the idle just under 500 rpms.

I now include AC control in my harnesses that allow the A9L to detect compressor activity and bump the idle accordingly as well as shut the compressor off during WOT and cranking. I'm still running a system like described above since a MegaSquirt 2 does not have the outputs to wire in a AC shut off relay. When I build my MS3 harness and ECU I'll probably use an input and output to mimic the A9L function.

The point of my long-winded reply is that you should be able to trip the compressor completely independent of the GM ECU without to much of an idle drop. If you do get one then creating a controlled vacuum leak (I guess "dedicated Idle Air Bypass" sounds better) should take care of it.

-Jason

Don't you have AC on yours Pat?

+1 on the NA buy! Gunpilot has knack for finding the deals out there!

I have a feeling you could sell a bunch of these Jason. If there is an LS car close to you it wouldn't be hard to measure one up. I have a bunch of photos of Shannons lines somewhere and I'm sure he would be glad to measure or take photos whatever for us.

After hauling around a compressor that does nothing for 3 years and 18,000 miles I'm really excited about the possibility of having working AC! Thanks for posting this Rawn!

A couple shots of Shannons
https://www.v8miata.net/attachment.p...ine=1441375406
https://www.v8miata.net/attachment.p...ine=1441375406

Just picked up a LS2 compressor and was disappointed to find it was way too large for the space. Pulley was hitting the radiator hose and outlets were too close to frame to accept adapter I bought.
https://www.v8miata.net/attachment.p...ine=1441407530

https://www.v8miata.net/attachment.p...ine=1441407530

I did not want to rework the radiator mounting, so I went back to the Miata compressor. Using parts off the donor, I was able to do this:
https://www.v8miata.net/attachment.p...ine=1441407530

https://www.v8miata.net/attachment.p...ine=1441407530

Everything is not fully tightened down yet, but with some slight shimming I was able to mount up the Miata bracket and Miata compressor in line with the LS2 crank. There is no tensioner, so I will have to install the belt, and then the compressor to the bracket. Hopefully the LS motor does not over rev the Miata compressor! Im sure it will take a few trials in shimming to ensure the belt is straight, but looks good with naked eye. Best part is, I should be able to use Miata connections. Putting kids to bed now, and back in Garage I go.

Wow didn't see that one coming. I wish I would have looked at that before I sold my Miata compressor! Red line on the 1.8 is higher than the LS so if the crank pulley is about the same size you should be fine.

Anyone want swap an LS1 compressor with 49,000 miles on it for an NA one? :)

Lol. Well, it's on the opposite side of the motor and upside down in the LS, so there is still some fabrication ahead. I'll keep you posted.

Ahhh you might not be able to run that puppy upside down. I'm not sure about radial ones but the old piston compressors had an oil reservoir in them and had to be reasonably level.

Way to rain on my parade! lol. Did some research, and you appear to be correct. Max "clocking" recommended seems to be 90 degrees. It is recommended discharge line be on top. Back to the drawing board. Seems like I have 3 options now:

1. Find an AC compressor that will fit in that space with correct line placement
2. Move radiator forward so pulley clears hose
3. Switch to a Sanden compressor and bracket to move it up higher on the engine. This is assuming I would still have hood clearance.

I heard rumors that an early LS1 compressor has the AC line fittings coming out of the back instead of the side. I'll look into that today.

At least I got all the controls installed and the fans working as advertised. JUST NEED A COMPRESSOR THAT WORKS!!

LOL always glad to help! ;) Check out Shannons photos up there ^. F-body LS1 compressor and lines fit like an ass on a pot on mine too. I don't have my hard lines on mine now but they do come straight out the back and clear the headers fine. I'll get some shots and post them up for you this morning.

Tried to get some pics on mine but not happening with it on the ground, sorry.

Any F-body? So what year and model vehicle would I try when asking at a parts place? Older Camero?

I know for sure 99 to 02 Firebird or Camaro will work and they are all the same. Not sure on 98 but probably the same. Nothing older as 98 was the first year of LS in the F bodies.

Ref Shannons is a 99 Firebird and mine is an 02 Camaro and I know nothing but the intake manifold and cam changed between those years.

I looked through my photos and don't have squat on how it fits really. Here is one in the air that shows the Fbody hoses with the Miata headers.
https://www.v8miata.net/attachment.p...ine=1441472938

These are old Sanderson headers though so yours might look a bit different.

OK got some pix for you. Not sure why your radiator hose is in the way, it's the sway bar that is usually the issue. I took the hoses off this spring but you can see them in the prior post.

https://www.v8miata.net/attachment.p...ine=1441500553[/URL]https://www.v8miata.net/attachment.p...ine=1441500553[/URL]
https://www.v8miata.net/attachment.p...ine=1441500553
https://www.v8miata.net/attachment.p...ine=1441500553
https://www.v8miata.net/attachment.p...ine=1441500553
https://www.v8miata.net/attachment.p...ine=1441500553

I did not assemble this car, so not sure how the radiator is supposed to mount. Looks like the factory brackets were used. It is not very forward in the car, and could possibly be move about 2 inches forward if needed. I'm starting to evaluate the Sanden high mount AC kit with the Sanden mini ac compressor

Well, just swapped the 2006 LS2 GTO compressor for a 2000 LS1 Camero compressor with fittings in the back.
https://www.v8miata.net/attachment.p...ine=1441821829

Looks like I will go this route and try to relocate my radiator forward to clear the hose.
Now I need to determine if I want that adapter to have straight threaded fittings coming out, or the 90 degree bends like I ordered?

Installed the new F-Body compressor, and it still hits the radiator hose like the GTO compressor.

After seeing Jim's pictures, I'm wondering:
1. Is my radiator installed to far back, or
2. Is my engine installed too far forward?
+
I remember when I posted a picture of my oil psi switch, someone made a comment about how I was able to get that picture because on their car it was all up against the firewall.

Is the V8R subframe notched to allow the engine to be slide back and forward? With exhaust done, this may not be an option.

To move radiator forward, I will have to drop it about 1.5inches and cut away the front core support like I did on the 302 car to push it forward about 2 inches. Always something.

Nope, never got it all put together. I do have the CTSV front drive accessories on my LS2 with the the compressor just sitting there, bolted against the block with the V8Roadsters adapter block bolted onto the rear of the compressor. Sorta got lazy and haven't worried about AC until now I guess...

In reading thru what Gunpilot is going through now, he and I have different set of clearances in that area under the hood. I believe I had to tilt my radiator forward at the bottom to make it more vertical than the original Mazda one was, but the top of my radiator is in regular location. ...if anybody can figure it out, GP can! (And Jim too!)

Decided I'm gonna drop the radiator down and forward like Jason did (and I followed) on our Ford builds. This should give me plenty of room. Found this website that had some good mounting ideas: Nathan's LS1 Miatahttps://www.v8miata.net/attachment.p...ine=1441976955

Sometimes to go forward, you have to take a step (or 2) back. LOL
https://www.v8miata.net/attachment.p...ine=1442007159

Got it mounted under the core support lip now. Used stock mounts reversed sides. Had to do some cutting and grinding, but seems to be solid. Still need a support on bottom, but at least radiator hose is off compressor. I will work on mounting up the condenser Saturday night. Once it is all mounted and sturdy, I will take it all out and paint everything.
https://www.v8miata.net/attachment.p...ine=1442007159
https://www.v8miata.net/attachment.p...ine=1442007159

So when did radiator hoses get so expensive? One of these was 15.00 and the other was 49.95!
https://www.v8miata.net/attachment.p...ine=1442103275

Holy crap batman! Think I'm a bit over whelmed here. Had the weekend to think about it.

So, I pulled out every AC line I ever hoarded in my garage. Laid them out to try and make this work without too much fab work. Think I have the condenser finally mounted to the radiator with some custom bracket work. Most of lines ran, and waiting for new AC compressor adapter in the mail today. Have a bit of time today to stare it down and make it work. Hopefully pictures to follow later this evening.

So close. Here is a picture of the brackets I made using some scrap aluminum and the stock radiator brackets:
https://www.v8miata.net/attachment.p...ine=1442256298

And assembled:
https://www.v8miata.net/attachment.p...ine=1442256298
http://i447.photobucket.com/albums/q...pshd1uexim.jpg

And installed:
https://www.v8miata.net/attachment.p...ine=1442256298

Need one spot weld on lower brace I made for radiator, and it should be good. New hose clears compressor. Now I am just waiting for the post man! lol.

Drier mounted using old bracket off of condenser. Finally got my compressor adapter in and mounted. Funny thing is, Jason's Ford lines fit on ends, but were to long for my application. I need to figure out if having this 90 off the compressor is best, or have the connections come straight out will be better. The space is very tight, and just about any routing will end up near the headers.

https://www.v8miata.net/attachment.p...ine=1442266847

I was starting to wonder if you had a boss frog frame with a V8R sticker on it! I guess the radiator was just farther back then. Hope that all goes in there well for you.

So what are you using for lines there?

I may be wrong (probably), but I think the condenser should be a lot closer to the radiator than that. The air should have no choice but to go through the condenser. Unless you have some ducting that is going around it that isn't in place yet.

I have mine spaced out a little too the same. I put one small fan on the front of the condenser pushing air into it to help out which comes on only when the A/C is on. I've learned that it is really important to have air flow through the condenser (like when at a stop light) other wise high pressure goes way way up really fast.

I spaced mine because I had issues with radiator cooling in my 302 when they were stacked. Trying something different on the LS2. I plan on putting a shroud on top and the sides when I have the plumbing all worked out. I'll be taking the car to the AC shop this week to see if I can get some custom lines done.

Took a bit to figure out how I wanted to do this, but have all parts on order. Here is what I'm using:

I have an LS2 motor with GTO accessories.
Using a 2000 Firebird compressor with connections on the rear of the compressor.
Using an adapter to turn up the compressor connection and turn them into threaded connections. One 3/4 and one 7/8.

Custom hoses will be:
Low side - M22 straight adapter to the evaporator, a number 10 hose with inline service port, 7/8 90 degree adapter to compressor
High side - M16 straight adapter , a number 6 hose with inline service port, a 90 degree M16 adapter to the dryer
Condenser - 3/4 90 degree adapter off of compressor with number 8 hose to a M20 straight adapter to the condenser.

All my adapter were from coldhose.com Once I have it all crimped and working, I can post links and part numbers.

I'm also going to put an inline pressure switch in the high side line. Ill be using a relay operated off the stock Miata button on AC controls to turn compressor on and off.

You know if you'd whip up a half dozen sets while you are at it you could pay for your efforts a few times over...

Got the parts in today:
https://www.v8miata.net/attachment.p...ine=1444339825

Once I have it installed and tested, I can definitely get some more sets fabbed up. Had to tackle some wiring issues today, but finally got the factory AC switch to activate the factory relays. Hopefully I will have time next week to get the lines done and installed. I think this will be a good solution as all lines will be soft and routed away from the headers.

New fittings look good and seem to fit.
Here is adapter and 90 degree bends for compressor from the bottom.
https://www.v8miata.net/attachment.p...ine=1444418903

And from the top
https://www.v8miata.net/attachment.p...ine=1444418903

For the wiring, I ran into issues since the PO had removed all the interior Miata harness that originally ran to the Miata ECM. I found some good stuff on Flyin Miata and followed this:

Cut the light green/black wire on A/C high pressure switch (on the aluminum A/C tube). Attach the switch side of the cut wire to the stripe side of a diode. Attach the other side of the diode to the blue/black trigger wire at the A/C clutch relay. Don’t crimp this side yet, see below. Now when you press the A/C button it triggers the AC clutch relay directly, and the diode is in-line to prevent back-feeding.

You must now run a jumper wire with another diode teed between the blue/white trigger wire at the condenser fan relay & the blue/black trigger wire at the AC clutch relay. Install the diode such that the stripe faces the clutch relay. You may now crimp the two that you were leaving for the T connection. Make sure to protect all diodes from shorting. Now the fan will come on with the clutch, but the clutch will not come on with the fan.

This is all under the hood at the factory relays. I have both my radiator fans running off the coolant switch and adding a separate fan for the condenser activated as stated in the instructions above.