Opinions on PWM fan controllers

[andrewb70]

Originally Posted by Larry R

How does one incorporate operating an air conditioning compressor in your set up? I have seen some ideas on the forum, but am still not sure how to do it.

Thanks, Larry

Larry,

I don't have AC, so I can't help. Others have done this, so hopefully they will give you some input. The following is a guess:

The AC compressor is controlled by the VA computer and not by the engine ECU. The ECU monitors AC pressure and coolant temp and adjusts the fan speed accordingly.

Andrew

[Larry R]

Originally Posted by andrewb70

Larry,

I don't have AC, so I can't help. Others have done this, so hopefully they will give you some input. The following is a guess:

The AC compressor is controlled by the VA computer and not by the engine ECU. The ECU monitors AC pressure and coolant temp and adjusts the fan speed accordingly.

Andrew

I am not familiar with the VA computer. Can you give me some insight? Thanks, Larry

[andrewb70]

Originally Posted by Larry R

I am not familiar with the VA computer. Can you give me some insight? Thanks, Larry

I wish I could, but as I said before, I don't have A/C on my cars.

Andrew

[Larry R]

Originally Posted by andrewb70

I wish I could, but as I said before, I don't have A/C on my cars.

Andrew

I wasn't trying to be obtuse, I did read that you do not have A/C. But since you mentioned the compressor was controlled by the VA computer, I was hoping you had some knowledge of that.

I have been studying this and I can see how to incorporate the PWM with the fans and my Holley HP, but not the A/C. One way I came up with to speed up the fans when the A/C comes on, is to use have the signal from the trinary switch go to a relay to shift the power to the fans from the PWM to a constant 12 volts for the duration of the higher pressure seen by the trinary switch. I would rather have it all go through the PWM but I don't believe I have enough I/O's with my HP to do this. Again, thanks for your input. Larry

[andrewb70]

Originally Posted by Larry R

I wasn't trying to be obtuse, I did read that you do not have A/C. But since you mentioned the compressor was controlled by the VA computer, I was hoping you had some knowledge of that.

I have been studying this and I can see how to incorporate the PWM with the fans and my Holley HP, but not the A/C. One way I came up with to speed up the fans when the A/C comes on, is to use have the signal from the trinary switch go to a relay to shift the power to the fans from the PWM to a constant 12 volts for the duration of the higher pressure seen by the trinary switch. I would rather have it all go through the PWM but I don't believe I have enough I/O's with my HP to do this. Again, thanks for your input. Larry

Toward the end of my Cougar build thread, I discuss how to configure the Holley software to have two PWM tables one for AC on and one for AC off. This way you can have the fans come on when the compressor is on.

http://www.pro-touring.com/threads/1...res-and-videos)

Andrew