87 Suburban 5.3 AC Setup Advice

[nobox351y]

Current budget minded plan:

Holley 20-160 Compressor kit w low mount
Stock 87 oem evap
02 condenser (87 condenser is available as well)
87 or 02 accumulator

Currently planning to run the wiring off of the 87 ac wiring, I have the ac plugs in the harness still, but do not have electric fans and the only issue I can see would be wanting to raise the idle w/ac on.

Biggest issue Im having with this hodge podge of parts is the different fittings that all these parts have.

Please poke holes in the plan, share pics of your set ups etc. Compressor should be here this week.

[Wgesnerjr]

I have been looking at this Holley kit for a while. I am starting to plan my install and have weighed out this kit or buying separately. For sure it will be mounted down low on passenger side with the Sanden SD7 compressor. (or an aftermarket equivalent) When you get your kit, please let us know and post pictures!!

for my set up, I am using the 1985 condenser, Receiver/Drier and evap core. Since my PCM is a 2003, it needs a serial data signal to work the compressor. So i will just be using the 85 wiring set up since I have an engine driven fan.

[nobox351y]

wge- Ill be sure to take pics. Have you looked at the wiring side? I have limited experience with ac and heat. Typically have stuck to trying to go fast and deleted all this stuff. Now its time to go on power tour with my dad, and its my daily, so AC would be nice.

[Wgesnerjr]

I was lucky that my wiring harness is in good shape. The only issues mine had was the green wires that comes off the plug at the firewall and went to the A/C compressor and the Idle Kick up Solenoid. Those were "cooked" from years of sitting on top of the old 305. So I will be re-creating a wire from that firewall plug down to the new Sanden compressor.

My thought is that it will kick the compressor on and off just like original. The only issue is the Idle Kick up, but others have said they did not have a problem running without it. I will give it a try and see how it goes.

If it doesen't work out, there is a very expensive little box that can alert the PCM data wire of the request for A/C, but i will wait to see if I need it before buying.
http://www.rpmextreme.com/Product/23...st-Module.aspx

[nobox351y]

Ill have to take a look at it and see if I still have that wiring or not. I am guessing it was still there before I pulled the 454, but I might have clipped it when I pulled it.

[rennat_2006]

I finished up a ls swap for a customer on a 72 c10 and didnt bother to hook up the ls ecm to the stock 72 ac system. The compressor would engage and kick down the idle rpm like 100rpm for a split second and the iac would counteract it and get it back where its desired was.

Now if your running electric fans i would definetely hook it up to kick the fans on automatically with the compressor.

[ls1nova71]

What year is your engine/PCM? That will dictate how easy it will be to incorporate the A/C into the PCM.

[nobox351y]

Nova- thanks for chiming in. 01 engine and pcm.

This is what I have for the 87 side of the wiring. Not sure where the compressor engage signal should come from.

[ls1nova71]

Well, I looked and cant find a schematic on an '87 Chevy truck. But basically what you would do is reuse the low pressure switch on the accumulator, and the wires on it would be wired differently. One wire would go to ground and the other would go to the C2 connector pin 55. The A/C request wire should run through a high pressure switch, but you can go without it, but you wont have any over pressure protection (Not recommended). The A/C request would come from the switch under the dash somewhere, but it will be one of the two wires that are on the low pressure switch now. You could use a test light to figure out which one it is, but I suspect it will be the light green wire. The request would go to C2 pin 17. Then you would need an A/C clutch relay which would be powered up by the ignition terminal 86 on the relay, and controlled by C2 pin 43 which would go to terminal 85. The remainder of the relay would be constant hot on terminal 30 and terminal 87 would go to the compressor. It sounds harder than it actually is, I think once you started it, it would make more sense. Hope this helps.

[nobox351y]

-Nova thanks for the help with the wiring. I will take a look at it. That may be simpler as I think I deleted some of the stock wiring when I removed the tbi.

Any one have any suggestions on the size of hose to run?

Evap accumulator has a -12 male fitting going to -10 compressor fitting

Compressor discharge is -8 to condenser -6

Ease of the layout, -12 to -10 fitting off accumulator to -10 at the compressor


Compressor discharge -8 to condenser with a -8 to -6 fitting

This is what I was thinking, but I know very little about AC theory and what would be more efficient.

[nobox351y]

Well, getting closer to getting this project rolling. New evap, condenser, and accumulator. Came in today. Just waiting on the compressor.

Does anyone have a source for the condenser mounting isolators, or part numbers? LMC brothers dont have them listed, struggling to find the ac delco number.

[87chevy.com]

I ran stock 87 evap, condenser and accumulator with the stock LS compressor with zero problems. Cooled fine. They make a stack plate type of condenser that is supposed to be better for r134 than a stock tube fin condenser.
Clint