I've been using VSS as part of my fan control strategy, but from experience I can say that it isn't really needed. Personally if a car has A/C it makes more sense to do CTS vs. A/C pressure. If no A/C then you can do CTS vs. engine oil temp.

Andrew

How does one set up a CTS vs A/C pressure? Where and how do you get A/C pressure. My car has a trinary switch is that used? I do have a VSS in my car but I am intrigued by the idea of using A/C pressure.

Thanks, Larry

We just did a Dominator in a 32 and we used a holley 500 PSI pressure transducer. This allowed us to skip the binary switch and the gm pressure sensor and do it with one sensor. We control the pwm fan and control compressor clutch engagement (high and low pressure cut off) through the ecm.

So far, it works.

Interesting concept, and since it works, worth considering. I do like the idea of having the fans either go off or be drastically slowed down at speeds above, say, 55 to 60 mph. I'm new to the PWM idea so I have a lot to learn. Thanks.

What threads does the Holley 500PSI transducer have? Thanks, Larry

One eighth NPT.

Andrew