e-fans that turn on at 250 psi

[gearheadnate]

Check out this fitting I made. I hooked up my fans to operate on a/c presure. I don't have the pin in the pcm turned on to operate the fans, so I made another fitting to go in line with the heater hose, that turns the fans on at 195. I still need a bigger alt.

home made a/c fitting $30
home made coolant fitting $5
250 psi a/c switch $30 part # redot 71r6230
coolant switch 195 $40 part # jet 60600
34" radiator $260 from the Radiator Barn.com
e-fans $175 ebay
rocker switch $5 radio shack

total out of poket $545

[Hit Man X]

Badass!!! This is what another member and I have been discussing in the background.

Few questions, do your fans come on at 50% power then switch to 100%?

High side AC pressure vaires from climates, system capacity, etc. Is 250psi the best choice for an average pressure?

Are fans off at freeway speeds provided motor is below 195°F? Or could you run a harness to control fans for 50/100% speeds and use the pressure setup to dictate when the fans kick on and off?



Thanks, I may have to hit you up for some of this!

[rosscob]

IT'S A BEAUTIFUL FITTING!!!!!!

What, I'm sure, we really want is some more detailed instructions on the specifics of how this fitting was fabricated.

This is sweet!!!!! With Allen's harness and this pressure switch the fans would no longer activate at highway speeds when they are not needed, unless you were overheating in which case you have bigger problems.

Sitting in traffic the fans would not cycle with the A/C and would remain on while pressure is above 250.

[gearheadnate]

Hitman,

I wired it to operate only # 2 fan on high for the a/c and it only runs in stop and go trafic. I could not find a presure switch lower than 250 psi, the fans turn off at 240 psi, 225 psi would be best. I can not find a dual stage switch to make the fans operate at 50% and then 100%. To make the fans turn off at a certain presure you would need to create a latching circuit and run it though a aux. low presure switch. I am leaving on vacation for a week and will give more detail when I get back.

Thanks Nate

[Hit Man X]

Give us the low down when you return.

I don't mind fans on at 100% when needed in town, on the freeway is another matter.

[SlammaDingdong]

Originally posted by Hit Man X@Sep 29 2005, 01:39 AM
Badass!!! This is what another member and I have been discussing in the background.
.....

Thanks, I may have to hit you up for some of this!

One of the next mods on my slate when time allows it. Thanks Nate!

[gearheadnate]

Well I'm back from vacation, hit me with your questions

[GMCwantsLS1]

Here is your high/low pressure fan switch! http://www.oldairproducts.com/shop/product...fce3a69a48b0fc2

[Hit Man X]

Here's what I was thinking on doing...

Running a relay harness (either from Allen or build my own). That way fans run at 50/100% power dependant on temperature.

Take the lead wire from that harness to the AC compressor and hook that to the 250psi pressure switch. It appears it works via a ground...



Am I totally off base here?

[gearheadnate]

So you thinking of running the fans on low with engine temp and switch to high speed when there is a demand for fans from the a/c and with engine temp?


That old air products switch is a trianary switch.
If I remember right trianary switches operate off of the low side.