Holley HP and MPH

[Tony V]

What are folks using to read MPH in the HP system? curious to understand how and possibly use it for my PWM controller for my fans.

Thx Tony

[gray86hatch]

What trans. It will work with almost any input just have to create the input strategy to control your fan output

Tim

[will69camaro]

I have dominator but using VSS for speed in my system. Will setup the fans against speed/temp/ac/etc.

[Tony V]

What trans. It will work with almost any input just have to create the input strategy to control your fan output

Tim

using a tremec 6 speed.....currently my fan is working but only using CTS temp, i'd like the option to turn them off at a certain MPH.

[will69camaro]

How many of your inputs do you have left with the holley?

Do you have the vss sensor on the trans? Can wire it into Holley for the mph signal and set conditions against that.

[Tony V]

How many of your inputs do you have left with the holley?

Do you have the vss sensor on the trans? Can wire it into Holley for the mph signal and set conditions against that.

yes, i've got a VSS sensor, i'm currently only using one output and zero inputs so I have plenty of I/O room. although i was using the VSS to drive my speedometer and not sure if I could "split" the signal to both the speedometer and HP.
I also read that VSS sine wave couldn't be read by the HP, that i either needed to convert it to a square wave digital signal or find use a different sensor that outputs a digital signal. not sure if there's any truth to that....but i can try.
thx for the input

[andrewb70]

The HP can't use a stock VR style VSS, only Hall effect. The Dominator can read both.

Andrew

[Tony V]

The HP can't use a stock VR style VSS, only Hall effect. The Dominator can read both.

Andrew


Thx Andrew......i'll bag the idea for right now.

[will69camaro]

Just touching on this, do you need to reference the speed? If it's PWM, just have it turn down as it approaches desired temp. As speed increases, temp will drop and the fans will as well without needing to reference the VSS.

Just a thought.

William

[Tony V]

Just touching on this, do you need to reference the speed? If it's PWM, just have it turn down as it approaches desired temp. As speed increases, temp will drop and the fans will as well without needing to reference the VSS.

Just a thought.

William

I was going to control the fan speed with CTS and Speed but getting a speed signal to the HP wasn't in my scope. right now its working based on temp.... a simple straight line slope as its getting hotter the PWM % increases.

[andrewb70]

Just touching on this, do you need to reference the speed? If it's PWM, just have it turn down as it approaches desired temp. As speed increases, temp will drop and the fans will as well without needing to reference the VSS.

Just a thought.

William

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

[Larry R]

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

[dontlifttoshift]

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.

[Larry R]

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.

[Larry R]

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.

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

[andrewb70]

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

One eighth NPT.

Andrew