Dual Fan With A/C Control

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Raymond_B
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Dual Fan With A/C Control

Post by Raymond_B »

I am working through controlling two fans along with using the A/C related features like idle up, one fan on when A/C is on, RPM based A/C cutoff etc. Can you guys sanity check my thinking? If possible i'd like to reduce the number of I/O pins I am using, but I'm not sure I can.

Pins proposed to use (MS3/3X):

Boost --- fan 1 ground relay trigger. Set in Fan Control to come on at specific temp and on with A/C

Nitrous2 --- fan 2 ground relay trigger Set from Programmable On/Off Outputs 1 for specific temps

Nitrous In --- AC ground side input (Idle Up Input in TS) Is this simply a pin to signal the MS that A/C is active? **Or** is it also a constant pin providing ground that can cut that ground when specified settings are hit (like TPS based A?C shutoff)?
1995 Ford Lightning. Dart based 427 Windsor, Novi 2000, full sequential, E-85, etc. MS3X/v3.57
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Raymond_B
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Re: Dual Fan With A/C Control

Post by Raymond_B »

Bump


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goodysgotacuda
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Re: Dual Fan With A/C Control

Post by goodysgotacuda »

Raymond_B wrote:I am working through controlling two fans along with using the A/C related features like idle up, one fan on when A/C is on, RPM based A/C cutoff etc. Can you guys sanity check my thinking? If possible i'd like to reduce the number of I/O pins I am using, but I'm not sure I can.

Pins proposed to use (MS3/3X):

Boost --- fan 1 ground relay trigger. Set in Fan Control to come on at specific temp and on with A/C

Nitrous2 --- fan 2 ground relay trigger Set from Programmable On/Off Outputs 1 for specific temps

Nitrous In --- AC ground side input (Idle Up Input in TS) Is this simply a pin to signal the MS that A/C is active? **Or** is it also a constant pin providing ground that can cut that ground when specified settings are hit (like TPS based A?C shutoff)?
I can try to help but am not sure.

The ECU is setup to be the controller for the a/c compressor for the features to work correctly.

To do this you need to have an "a/c request" input to the ECU. The ECU will then bump up the idle and use the controls shown in tuner studio to actuate the compressor relay [ground]. This is how you will get it to function right, cutout with tps, etc.

To control two different fans I would use fan 2 as the output of the "fan control" settings. I am not sure how you setup the second fan to run with both a/c and temp with current options in tuner studio. I would probably just setup fan two to run with the a/c compressor(?)


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Matt Cramer
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Re: Dual Fan With A/C Control

Post by Matt Cramer »

The output settings look good, but the nitrous in pin works backwards from other switched inputs - it needs 12 volts. This pin is simply the input to let the MS3 know that the A/C has been commanded to turn on - if the MS3 is controlling the A/C on a separate (third) output, it can decide if it will turn on the A/C or ignore it based on other conditions.
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Re: Dual Fan With A/C Control

Post by Raymond_B »

Matt Cramer wrote:The output settings look good, but the nitrous in pin works backwards from other switched inputs - it needs 12 volts. This pin is simply the input to let the MS3 know that the A/C has been commanded to turn on - if the MS3 is controlling the A/C on a separate (third) output, it can decide if it will turn on the A/C or ignore it based on other conditions.
Gotcha, OK that's easy enough to swap. But where else in TS would I control the AC operation? Like cutting it at WOT? Or would I have to get creative with wiring to accomplish that?
1995 Ford Lightning. Dart based 427 Windsor, Novi 2000, full sequential, E-85, etc. MS3X/v3.57
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goodysgotacuda
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Re: Dual Fan With A/C Control

Post by goodysgotacuda »

Raymond_B wrote:
Matt Cramer wrote:The output settings look good, but the nitrous in pin works backwards from other switched inputs - it needs 12 volts. This pin is simply the input to let the MS3 know that the A/C has been commanded to turn on - if the MS3 is controlling the A/C on a separate (third) output, it can decide if it will turn on the A/C or ignore it based on other conditions.
Gotcha, OK that's easy enough to swap. But where else in TS would I control the AC operation? Like cutting it at WOT? Or would I have to get creative with wiring to accomplish that?

Turn those features on in the "Startup/Idle" drop down. Near the bottom.


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Re: Dual Fan With A/C Control

Post by Raymond_B »

goodysgotacuda wrote:
Raymond_B wrote:
Matt Cramer wrote:The output settings look good, but the nitrous in pin works backwards from other switched inputs - it needs 12 volts. This pin is simply the input to let the MS3 know that the A/C has been commanded to turn on - if the MS3 is controlling the A/C on a separate (third) output, it can decide if it will turn on the A/C or ignore it based on other conditions.
Gotcha, OK that's easy enough to swap. But where else in TS would I control the AC operation? Like cutting it at WOT? Or would I have to get creative with wiring to accomplish that?

Turn those features on in the "Startup/Idle" drop down. Near the bottom.


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Right, but how does the MS actually turn the A/C off? It has to interrupt compressor, so I imagine it's via a relay and that's the part that's missing to me. Maybe I have overlooked another input/output?
1995 Ford Lightning. Dart based 427 Windsor, Novi 2000, full sequential, E-85, etc. MS3X/v3.57
http://www.buildpics.org/
goodysgotacuda
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Re: Dual Fan With A/C Control

Post by goodysgotacuda »

Raymond_B wrote:
goodysgotacuda wrote:
Raymond_B wrote: Gotcha, OK that's easy enough to swap. But where else in TS would I control the AC operation? Like cutting it at WOT? Or would I have to get creative with wiring to accomplish that?

Turn those features on in the "Startup/Idle" drop down. Near the bottom.


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Right, but how does the MS actually turn the A/C off? It has to interrupt compressor, so I imagine it's via a relay and that's the part that's missing to me. Maybe I have overlooked another input/output?
You want the ms to control the compressor relay via ground. I would think you could use whatever ground that is on the compressor now as the a/c input [request] into the ms


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tryingbe
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Re: Dual Fan With A/C Control

Post by tryingbe »

Raymond_B wrote: Right, but how does the MS actually turn the A/C off? It has to interrupt compressor, so I imagine it's via a relay and that's the part that's missing to me. Maybe I have overlooked another input/output?
I'd check your vehcile's wiring diagram and look for "a/c cut out relay" or "WOT relay". I set my MS to control that relay for my car, Dodge Omni.
1985 Dodge Omni GLH Turbo MicroSquirted 367whp http://www.msextra.com/forums/viewtopic ... 04&t=67324
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Re: Dual Fan With A/C Control

Post by Raymond_B »

tryingbe wrote:
Raymond_B wrote: Right, but how does the MS actually turn the A/C off? It has to interrupt compressor, so I imagine it's via a relay and that's the part that's missing to me. Maybe I have overlooked another input/output?
I'd check your vehcile's wiring diagram and look for "a/c cut out relay" or "WOT relay". I set my MS to control that relay for my car, Dodge Omni.
Right, and to do that I'll need another I/O pin, but I just wanted to confirm it. Do you have that pin to always be on (grounded) and then the MS interupts it to kill the A/C?
1995 Ford Lightning. Dart based 427 Windsor, Novi 2000, full sequential, E-85, etc. MS3X/v3.57
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tryingbe
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Re: Dual Fan With A/C Control

Post by tryingbe »

Raymond_B wrote: Do you have that pin to always be on (grounded) and then the MS interupts it to kill the A/C?

Correct.

My AC cut off is activated when
TPS > 70%
or
seconds < 20
1985 Dodge Omni GLH Turbo MicroSquirted 367whp http://www.msextra.com/forums/viewtopic ... 04&t=67324
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Re: Dual Fan With A/C Control

Post by Raymond_B »

tryingbe wrote:
Raymond_B wrote: Do you have that pin to always be on (grounded) and then the MS interupts it to kill the A/C?

Correct.

My AC cut off is activated when
TPS > 70%
or
seconds < 20
Awesome, thank you for the confirmation.
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Drew442
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Re: Dual Fan With A/C Control

Post by Drew442 »

In order for the MS to control the AC I'd have it interrupt the pressure switch. Your dashboard wiring remains the same and you command AC on with the dashboard. In normal operation the pressure switch interrupts and completes the circuit to operate the system. You'll need a normal ground switched circuit on the MS to be normally closed and then open circuit when there is a condition that you don't want the AC to operate. The driver commands AC on, the MS indicates a condition the AC is not allowed and the AC needs to be able to switch on and off as per normal operation.

In regards to your fans, if you have two I would run them in series when the AC is on but the engine is below running temperature. This is in order to maintain the condenser temperature but still allow the engine to warm up quickly. Then once the engine is at operating temp you can run them in parallel.

I'm on my phone so I can't draw a diagram but I think you'll be able to do this with the AC dashboard switch and one ground switched circuit on the MS

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Re: Dual Fan With A/C Control

Post by Raymond_B »

Thank you everyone for your input, this is a very basic diagram. MS controls both cooling fans, fan 1 comes on any time AC is on regardless of temp. Fan 1 and fan 2 will have separate temp thresholds if AC is not on. The MS will constantly ground the high pressure switch (Thanks Drew) and interupt when whatever settings are reached. Finally the AC on signal will come through Nitrous In.

Whew, I think I have everything covered :)

Image
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Drew442
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Re: Dual Fan With A/C Control

Post by Drew442 »

Rather than running fan1 or fan2, I'd recommend running both fans in series or both fans in parallel. That way the whole core is covered all the time.

http://i61.tinypic.com/28jbp1y.jpg


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Raymond_B
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Re: Dual Fan With A/C Control

Post by Raymond_B »

Drew442 wrote:Rather than running fan1 or fan2, I'd recommend running both fans in series or both fans in parallel. That way the whole core is covered all the time.

http://i61.tinypic.com/28jbp1y.jpg


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I'll look closer, I was worried about both fans coming on at the same time because they have quite a large startup amperage. The verbiage here is why I am running huge Tyco relays and really heavy gauge wire.

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Re: Dual Fan With A/C Control

Post by Drew442 »

It'll be both coming on at the same time at half the voltage. Current draw should be the same as one at a steady state. I don't know how to calculate the spike.

The speeding up should spike less than starting a second one from a stop though.

Either way, with properly sized components it shouldn't matter.

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Re: Dual Fan With A/C Control

Post by Raymond_B »

Drew442 wrote:It'll be both coming on at the same time at half the voltage. Current draw should be the same as one at a steady state. I don't know how to calculate the spike.

The speeding up should spike less than starting a second one from a stop though.

Either way, with properly sized components it shouldn't matter.

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OK, I see. Thank you for the explanation!
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jamies
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Re: Dual Fan With A/C Control

Post by jamies »

i have setup one vehicle which has 4 cooling fans, wired up as 2+2
if all 4 come in straight away with aircond it would pull the voltage down that far that it would near on stall, but having only two come on is fine
so these are the settings I used as a workaround, one pair of fans is delayed by 1 second when the a/c comp comes in.
Attachments
fan1.jpg
fan1.jpg (85.06 KiB) Viewed 1570 times
fan2.jpg
fan2.jpg (91.9 KiB) Viewed 1570 times
Drew442
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Re: Dual Fan With A/C Control

Post by Drew442 »

@jamies series or parallel?

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