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How can I fit a gauge to my Nitrous Bottle?

So you want to buy a gauge for your bottle and you have a Wizards of Nos System/Valve.


First thing to ask is...Where can I fit a gauge?

There are three locations described below with useful information to help you decide if that is the place for you:


On the rear of our maxflow valve.

Rear mounted gauge on won Maxflow Valve

What is the rear of a valve? For reference we consider the rear to be the opposite side to the outlet, in most cases identified by our red SPRV valve.

This is a good location as it is visible from most orientations.

The gauge is also linked to the bottle contents regardless of the valve position so can be read even when off the vehicle.

If purchasing a new valve this is an easy endeavor however if ordering  a gauge seperate to fit to an existing valve you would need to purchase two additional items. A gauge/sprv adapter as pictured above in addition to a reduced size SPRV with a 1/8th BSP thread. These can be purchased seperately or as a kit with the gauge. Also note that this requires the original SPRV to be removed so is only possible with a completely empty cylinder.


On the LHS of the valve.

Port Mounted Gauge on WON Maxflow valve

Which side is the left? The left side is as yours when looking to the valve from the rear as described above.

This position allows for constant gas pressure and is more tightly packed to the valve for a neat installation. When choosing this position however remember it's location. If the cylinder is mounted on the LHS of the vehicle then the gauge will not be seen in situ.

Important - Each maxflow valve has an unused part formed port on the LHS for the gauge. This is utilized by tapping and breaking in to the SPRV feed within  the valve. If choosing a new valve this would be done and gauge installed for you. If thinking about installing to your valve it would need these modifications doing by yourself, an agent or by ourselves. Please note all gas contents must be empty before modifying.


 On the outlet of the valve.

Gauge mounted externally on Maxflow Valve using 5mm Compression          Gauge mounted externally on Maxflow Valve using 5mm Compression

5mm Compression External Fitment

Gauge mounted externally on Maxflow Valve using 4AN Dual port adapter

4AN/6AN Style External Fitment

This is the most common method of attaching a gauge due to it's simplicity. Simply a suitable tee piece is supplied to match your outlet piping and the gauge is fitted to that. This does lower the gauge, so may not be the easiest to see in situ. It also is completely reliant on the valve being open to see the pressure so is only readable in situ or outside with the use of a blank. The gauge can be rotated to be veiwed from the LHS or RHS however is not visible from the rear of the valve.

Also note, if a transducer or heater pressure switch is already installed on the outlet of your system then you will need to check if your adapter already has two ports. If not a suitable twin port adapter would be required to install the gauge with your existing components.

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Yours Sincerely, The Wizards of NOS Team