VA Trinary to Low or Hi Fan?

[Shoeless]

Hey guys,

I've done a little research on this, but since my setup is a little different I'm having issues finding exactly what I'm looking for. I'm wondering if I should hook the ground signal wire from the VA Trinary switch to my Low or High fan. I'm running an LS3 with a standalone ECU that allows me to set 2 dimensional tables for the turn on temps for each of my fans separately. I plan one at a lower temp and another at a bit higher, or at least that is my plan. So I'm wondering if the low fan is already running, and the trinary switch activates the ground signal because it wants more cooling, would this work properly if I attach this ground signal to the high fan or should I put this ground wire to the low fan as well?

[KGTM]

One set is use for clutch, so in series with clutch, even though my controller still controls the clutch ,so safety.

The other when it hits pressure is getting high( I call this Mid pressure) and should turn fast to max otherwise next step is too high pressure ant will be too late and the clutch will be forced off until pressure drops.

In my car, when AC is turn on I force both fans on to about 1/3 speed, and will be at least at this speed as long as the AC is on, if the Mid pressure hits then I go to full speed. cool thing about his is is very quite and drops speed on highway as the fan is not needed at full speed most of the time.

Mostafa

[Shoeless]

Thanks for the response Mostafa. I would have to think this through a little going this path with my setup, but not impossible. I think I have a few spare inputs on the ECU that I could run the Trinary ground signal switch into and then have the ECU kick out the ground signal to the Infinitybox to turn the fans on and off. I'm pretty sure I can PWM my fans as well from my ECU and set up tables to back off fans at vehicle speed.

If I didn't go this path, it sounds like I should run the Trinary switch ground signal to my high (medium as you state) fan.

[KGTM]

no problem.

if your infinity box was easy to program, then when AC is on turn both fan to PWM at X speed and when mid pressure hits then turn both fans at full speed.

In my car the fan speed is totally relative to engine temp as hotter it get faster it goes and because of that my engine temp does not change much at all.

Mostafa

[jamesfr58]

Sean

I am using a Dakota Digital fan controller that turn on both fans when the compressor is turned on hooked to trinary switch. The thing I liked about the separate controller was the ability to set the temperature I want one fan to come on and then the second fan to come on as well as how long if any I wanted the fans to run after shutting the car off. If I were to use the circuit from the stand alone ECU I could not adjust the on off temperature or the after run and both fans would run then they come on so no high low fan option. However I am sure there is a way to program the ECU to perform the same duty and control the on off temperatures. :)

[KGTM]

I think the intent for turning fans on is not for engine temp as it for the AC unit to work properly and removed heat from condenser, unless you are talking about AC condenser temp. that is why the trinity wants full speed on when the mid pressure hit, only lower the speed or off once that condition is removed.

Mostafa

[Shoeless]

After digging into my AEM Infinity tuning software, and a couple emails to Jay at InfinityBox, I've got this all figured out. This was a great exercise in navigating the tuning software I've got for my standalone ECU, integrating it with the other systems in the GTM, and getting it to do exactly what I intend.

Likely not very relevant to the masses as this is very specific to my setup, but I'm pretty happy I was able to navigate everything so I'll share. I know there is a AEM Tuning thread on the MkIV thread as I popped over there to follow along with what those guys did.

These are the three states where fans will be required:
1. When A/C is turned on
2. Engine temp increases (2 sets of temps for low and hi fan)
3. If Trinary Switch trips in a high pressure (medium as Mostafa outlines) situation

Here is how they will be controlled:
1. The AEM Infinity has an A/C Request Input (likely similar to the OEM computer) that I can tap into in order to let the ECU know when the A/C is on and to adjust engine controls (RPM at idle - side note I can set a delay in the ECU in ms for when the signal is sent to the compressor before the engine makes adjustments since the compressor engagement isn't instantaneous). I have elected to use a digital input that I can set to ground on or +12V on. I'll tap into the +12V wire that is coming out of the Vintage Air compressor relay to feed into the AEM. So when the VA compressor relay kicks on to turn the compressor on, a +12V signal will feed into a the digital input on the AEM and now the ECU will know the A/C is on. Once the AEM knows the A/C is on, I have a nice little box to check for the AEM to turn the low fan on. The nice thing is I can also set up a general purpose high side output (+12V) to send a signal to the VA Full throttle switch to shut the AC off at whatever parameter I want (engine speed, throttle position,...). This fan request on signal will use the same lowside output listed in 2 below.

2. This one is the easiest. The ECU will have two lowside outputs that go into two separate inputs on the InfinityBox (low fan and high fan). I set temps for on and off and the ECU simply sends the ground signal to the InfinityBox master cell inputs. I will set the on and off temps at least 3-4 degrees from each other so they are not cycling on and off constantly.

3. After sharing a few emails with Jay and getting a better understanding on the programming of the master cell inputs, I can wire the trinary switch to an open master cell input that is programmed to turn both fans on to 100% if the trinary switch trips.

Thanks for the input guys.