Another A/C for SBC Swap thread (1 Viewer)

[Elbert]

The pusher fan I did on mine really did make a big difference.

My engine temps are no different with the AC running than with it off.

Yeah...that's next on the magic list. Ac is functional, I got the truck back this evening, drove it around a little bit...seems to sit on 200F with a/c running. I have to work tomorrow but over the weekend we'll see what she does regarding vent temps and radiator temps. May make some headway on getting pusher fan installed too.

 

[djawahir]

Elbert, I've got a v8 swap that I've been meaning to get A/C hooked up to. I've got GM compressor and Toyota everything else.

Do you need the relay to trigger the compressor? Do you have a wiring diagram for the tach signal to the coil, etc.?

I've got some GM manuals and I'll look to see if there is such a thing as an "idle up" switch for a/c (or other).

 

[Elbert]

Elbert, I've got a v8 swap that I've been meaning to get A/C hooked up to. I've got GM compressor and Toyota everything else.

Do you need the relay to trigger the compressor? Do you have a wiring diagram for the tach signal to the coil, etc.?

I've got some GM manuals and I'll look to see if there is such a thing as an "idle up" switch for a/c (or other).

SOme of my comments are based on reading the forum over time and taking their experiences into consideration.

I used a relay triggered by the factory toytoa a/c clutch wire to tirgger a relay that energizes the GM A/c compressor.

I don't have a wiring diagram. When I swapped engines I marked all of the main toyota wires that were important (a/c, coil, alt...etc) and so when this stuff comes up I know what wire was what just by that. A toyota manual should have the same reference. I can look to see what wire colors the specific toyota wire are if that would help?

On the A/C idle up... without digging into my gm shop manual...the PCM knows when A/C is requested via the controls on the dash....so it then increases the idle by a few hundred rpm... say from 600rpm to 800rpm. I'm paraphrasing but thats generally how it works on ECM controlled car. There is "some" a/c on signal which the ECM in turn increases the idle rpm.

So the idea on the ac idle up, is to figure out given my specific engine / ECM combination as to which wire the ECM is looking for to signal A/C on. Since I have a custom stand alone wiring harness that may be an issue since the harness may not allow for that, which would require that I establish a connection to the appropriate pin on the ECM itself.

 

[Elbert]

A/C Pics

see additonal pics of functional system. If anyone needs better pics let me know.

First pic is showing a relay that is on the passenger side firewall that feeds the compressor. Wiring is still under revision but functional.
2nd pic shows red wire tach signal from PCM feeding - negative side of coil.
3rd pic shows new GM compressor, you can't read in the pic but its a DENSO

 

[Elbert]

A/C Stuff

see 2nd group of pics.

1st pic shows the modified GM A/C hose mated with the evap core connection. OEM fitting removed, new fitting installed on hose, same for fiting that mates with the condensor from the other side of the compressor.
2nd pic (hard to see) but shows the black wire that controls the toyota OEM Ac compressor, and see where whire mates with it and then feeds back to relay.

Observations after having A/C for two days now...

Temp at the vent pull down to low 40's, I'm running R-12, engine temp runs between 200F and 215F, ambient temps last two days...low to mid 90'sF.

Issue...I need to control engine temp better at road speed (may need to modify fan shroud).

Given the present description and notes above...the a/c is entirely controlled from the Toyota dash. I do plan to install an aux electric pusher fan on drivers side of the radiator.

 

[Elbert]

another follow up...

The compressor does cycle...confirmed that over the weekend as temps cooled down around where I live. A/C is nice and was not that hard to do (once I was able to verify the path fwd). Appreciate those who offered insight and advice.

 

[Elbert]

I don't have a clue why older pics dont show up in this thread....they were posted to the forum and not linked from other hosting sites...