Complete A/C system swap possible?
I'm looking at getting a complete LM7 pullout from an '02 Silverado and making all of my own brackets to squeeze all of the accessories in. What would it take to go ahead and get the evaporator, condenser, accumulator and expansion valve from the donor and fit them into the car and working with the stock C3 controls?
So for the sake of argument lets say everything fits. Besides the lines and blower motor, am I missing any parts? What else would it take to make it work with the stock controls? I'm sourcing everything I listed from the junkyard to be a little under $200, so call it $300 for lines, fittings and blower motor etc. From what I've seen Vintage air it looks like $1400. So besides possibly size, why can't it work?
I know just enough about AC systems to really screw things up. But it seems to me you could wire a truck fixed displacement compressor from the original AC request line. The early 70 GM cars just ran the AC clutch wire through a thermostat and a binary switch.
Does that mean I wouldn't need the BCM or would that be going in line?
Trending Topics
I still have the variable compressor, which I really should replace with a fixed one. But the only problem I have is that it doesn't cool well after sitting in bumper to bumper traffic.. but all of times it blow 48 dregee. A new condenser would also help.
I still have the old Chevelle SBC compressor, which was a rebuilt unit that worked well...
BC
The Best V8 Stories One Small Block at Time
I'm not sure if converting to R134a requires a new expansion valve/orifice tube, but you could try to transfer over the compressor, lines, condenser, dryer, and pressure valves from the truck. Blow out your evaporator. And let us know if it works.
I'm not sure if converting to R134a requires a new expansion valve/orifice tube, but you could try to transfer over the compressor, lines, condenser, dryer, and pressure valves from the truck. Blow out your evaporator. And let us know if it works.
And then I found this thread. . .
https://ls1tech.com/forums/conversio...-solution.html
Been digging around all day when I came across that. I'll cut and paste some of the highlights for easy future reference:
#1
the car is a 1980 malibu 2 door(but this will work for every G-body 78-88) with factory heat/ac. i got the holley R4 bracket part number 20-133 ($130 from summit) and the install kit for the f-body/GTO accessories part number 21-2($60 from summit - comes with a spacer and hardware). the R4 compressor GM part number 88964863 (was used on TBI v8 camaros) i actually had but it runs @ $150-200. went to the U-pull it junkyard and got a condenser from an 87 cutlass($20), suction line($10) and high side line($10) - the 78-87 cutlass came with this style compressor mounted passenger side so it seemed like it was meant to be, and with a little tweaking here and there it fits great! it all bolts right in, i had to bend the line off the accumulator to get a better angle for the low-side hose. also had to bend the high side line a little (and have a high pressure switch port welded in).
i need to grab a belt tomorrow(according to my measurement it should take a 6PK2448) and modify the camaro radiator by cutting off the tabs for the factory condenser so it fits better. also need to move my trans cooler.
for the compressor control im going to wire it like it was a 2002 f-body (have the a/c request go through the pcm) so itll bump the idle up, turn on the fans, turn the compressor off @ WOT.
this morning i wired everything up permanently to be controlled by the ECM. basically 9 wires in a little stand-alone harness i made and tucked away since all the wiring was done 6 months ago -maybe this winter ill open it all back up and re-do it but for now its functional and not a show car by any means. the factory LS1 diagram has a diode in-line with the compressor clutch wiring so i put one it, fired it up and popped the fuse... so after some head scratching i ditched the diode and it worked fine (not sure if its the different compressor or whatever - the diode is supposed to stop voltage spiking back into the circuit). anyway, drove the car all day (it was 90* here today with high humidity) and it worked great. ECM controls everything, bumps the idle up when the compressor comes on, turns the fans on, yadda yadda yadda. overall very happy with how it works so far lol
p.s. FWIW I'm sure I came across this before and didn't click on it, but I found it when I googled "c3 corvette a/c request line"
Last edited by I Hates Rabbits; Sep 28, 2013 at 04:45 PM.
1. I have a full factory A/C setup from a 76 Nova. It is a VIR system and you have a POA system. You can choose to convert your evaporator, poa valve, or try to find one that fits into your existing box. My direction is to get a newer orifice tube system evaporator that fits since I believe I can do it for less than $100. If you choose to convert you will pay about $100 for an accumulator and a conversion that runs two tubes into one.
2. The next step is to match a newer condenser to the evaporator system, with an accumulator and orifice tube. The older systems again will work but this is just a preference. When you do this also get the lines.
3. Wire it with the newer pressure sensor, as a modern system along with the older stuff. A/C request, fans, etc. Since this is an 02 setup you can run a normal A/C request and you do not need a BCM to control this but you may have to program your PCM depending on the compressor setting.
Bottom line an original factory A/C system running modern internals for the A/C including the wiring where needed and the rest is original -vents, fan, heater core, etc. I got the idea from one of the guys here on the forum that did a 72 truck but he changed the box to fit his evaporator. I think his handle is 72 ls nova or something like that. I will look up his handle or link to his build it was a beautiful truck that he sold when he was done.
Basically I just blended the two HVAC boxes together and sealed it up. Then it was just a matter of hooking things up. My HVAC controls are stand alone, so it just takes the PCM a/c request signal and goes from there.
The smaller line was able to be tweaked to fit where I needed it.



This is an in progress shot when I was modifying the box.

One of the fun side effects... I can remove the entire system from the car without cracking a line. Its been out of the car for a few years, and I just put it back in. Started the car for the first time and the a/c still worked!

Im not sure if that gives you any motivation or not haha. But its def possible...depending on your car's engine bay.
J.
In other news we should have the "shop" done this weekend and ready to pull the engine Monday, getting reeeealy anxious!
I'm looking at getting a complete LM7 pullout from an '02 Silverado and making all of my own brackets to squeeze all of the accessories in. What would it take to go ahead and get the evaporator, condenser, accumulator and expansion valve from the donor and fit them into the car and working with the stock C3 controls?
ave to make hose lines to your vents and he said he used insulated dryer vent to make the vents with and that was biggest issue I already have a LS3 with the air conditioner compressor and I want to take the wiring harness for the AC system out of this Chevy truck but I am installing a new computer in wiring harness in my c3 I have even used the transmission out of the truck and I thought I was going to have to shorten the drive shaft but I didn't it fit perfect I had to make a lip for the crossmember for the transmission to set on the back of it besides that work perfe
c
ave to make hose lines to your vents and he said he used insulated dryer vent to make the vents with and that was biggest issue I already have a LS3 with the air conditioner compressor and I want to take the wiring harness for the AC system out of this Chevy truck but I am installing a new computer in wiring harness in my c3 I have even used the transmission out of the truck and I thought I was going to have to shorten the drive shaft but I didn't it fit perfect I had to make a lip for the crossmember for the transmission to set on the back of it besides that work perfect
The OP hasn't been here for 7 of them. Pay more attention to post dates











