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DIY Pressure Transducer question and build probably soon

  • John Curtis
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19 May 2020 21:42 #40097 by John Curtis
Hey folks, have any of you built your own pressure transducers? I’m going to tackle a build soon and thought I’d see what you guys have used for yours along with possibly some captures and any input you have before I jump into it.

I’ve noticed on some builds you don’t see all 4 cycles. On the two builds shown in the videos below you can see everything a WPS500 would show, maybe not with the voltage and resolution but enough to diagnose for sure!

Here’s what I’m planning on copying


And here’s a similar one in use

Thinking out loud always helps me in the process.

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19 May 2020 22:25 #40099 by Dtech494
For the small investment it is worth trying and making your own transducer.
Some of them do not give the best transitions or resolutions. So it may be hit and miss. Often if you AC couple you get the best signal to display.
Input voltage and scaling on your display can also make a difference.
Some transducers are designed better for displaying rapidly changing pressures.
But if you make a harness and use that 3 pin connector (GM TPS ) style connector then you can easily swap them.
You will likely find having a 300 psi and 100 psi one to be useful.
The 100 psi one displays running compression better while a 200 or 300 psi one is better suited for cranking compression.
For vacuum waves a GM map sensor works excellent (with a 9v battery supply)
A GM fuel tank pressure sensor makes a good tail pipe pulse indicator (with a 4.5 volt battery supply.)
Or a peizo buzzer closed in a container makes a good tail pipe pulse tool.
I've made all of the mentioned and had them work sucessfully all be it each
suited for their own individual purpose.


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The following user(s) said Thank You: Noah, Tyler, John Curtis

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20 May 2020 09:58 #40102 by Matt T

John Curtis wrote: I’ve noticed on some builds you don’t see all 4 cycles.


Those were probably 0-XXX gauge pressure transducers which output zero at atmospheric pressure. Called psig in English units.

What you need is a transducer that's for 0-XXX absolute pressure. 0 absolute is hard vacuum so it'll output a little under 15 psi of voltage at atmosphere. Easy math example a 0-5 v 0-150 psia transducer will output about 0.5v at atmospheric pressure.

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  • John Curtis
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21 May 2020 17:30 #40110 by John Curtis

Dtech494 wrote: For the small investment it is worth trying and making your own transducer.
Some of them do not give the best transitions or resolutions. So it may be hit and miss. Often if you AC couple you get the best signal to display.
Input voltage and scaling on your display can also make a difference.
Some transducers are designed better for displaying rapidly changing pressures.
But if you make a harness and use that 3 pin connector (GM TPS ) style connector then you can easily swap them.
You will likely find having a 300 psi and 100 psi one to be useful.
The 100 psi one displays running compression better while a 200 or 300 psi one is better suited for cranking compression.
For vacuum waves a GM map sensor works excellent (with a 9v battery supply)
A GM fuel tank pressure sensor makes a good tail pipe pulse indicator (with a 4.5 volt battery supply.)
Or a peizo buzzer closed in a container makes a good tail pipe pulse tool.
I've made all of the mentioned and had them work sucessfully all be it each
suited for their own individual purpose.


A


This is very insightful!

Thinking out loud always helps me in the process.

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