Pressure Sensors

This one hurt my brain researching. 🌪

So pressure sensors, which ones, which manufacture, brand?!

Few things to explain first;

PSIa = Absolute (This is always used for MAP sensors, These sensors show vacuum)

PSIg = Vented Gauge ( A vented gauge sensor is always open to atmospheric pressure, It will read zero when the pressure is released, no matter how much atmospheric pressure changes)

PSIs = Sealed Gauge (A sealed gauge sensor means that the atmospheric pressure is sealed in at around 1 bar, so with zero pressure it’s possible it will read lower / higher than zero)

PSIg is the way to go for fuel sensors, the reason for this is when setting your fuel pressure at lets say 43.5PSI (3BAR) then you know the FPR is @ 43.5PSI, where with a PSIs depending on your sea level it’s possible you are of slightly off. In reality it’s not really a issues once tuned.

PSIs is the way to go for oil pressure, reason for this is the oil pressure relief valve does not care about atmospheric pressure, so if your wanting to setup oil pressure safety feature with your ECU the PSIs sensor will always read the same pressure at whatever sea level you are at.

Again in reality the difference wouldn’t be enough to complain about anything, plus the pressures I’m running would never demand the higher burst pressure of a sealed gauge over the vented gauge.

So which sensor manufacturer/ Brand?

There are two manufacturers that I’ve narrowed it down too;

Holleywell Sensors
MLH Range- Datasheet

SSI Sensors
P51 MediaSensor Range – Datasheet

You may not be familiar with these manufacturer, to which one looks very similar (IS THE SAME) to a very well know brand! Can you guess who? Let me know in the comments! 😎

Both are extremely good and are built for extreme environments / use. You won’t find a more bullet proof sensor, They handle pretty much any fuel & oil that any Motorsport team would chuck through them plus being more accurate compared to the Brass alternatives.

They are also much cheaper than the re-branded versions. 💲💲

A good tip when choosing a pressure sensor, spec it to the range your going to see, so my fuel pressure is never going to go over 100PSI so me using a 150PSI will loose resolution as you only have .5v to 4.5v voltage range.

What am I running then? 🤷‍♂️

(1/8NPT Thread Port)

Honeywell
‎MLH150PSB06A‎ – Oil Pressure 150PSI Sealed Gauge
MLH100PGB06A‎ – Fuel Pressure 100PSI Vented Gauge

OR

SSI
P51-200-S-G-P-4.5V-000-000 – Oil Pressure 200PSI Sealed Gauge
P51-100-G-G-P-4.5V-000-000 – Fuel Pressure 100PSI Vented Gauge

✌ HONEYWELL WON ✌

Reason for this is they were in stock. 😜

I really couldn’t decide otherwise as they are equally as good and are no doubt overkill for my needs as you can see from the datasheets but I wanted a sensor that wasn’t going to let me down and take abuse.

I hope you find this useful. ✌