Nitrous pressure should be kept consistent to obtain optimum performance. All NOS systems are designed to work best with a bottle pressure of 900-950 PSI. Pressure is determined by the amount of nitrous contained in the bottle and temperature. Accordingly, it's a good idea to use an NOS bottle heater and/or blanket. Likewise, maintaining consistent line filling is important...which is why most racers use an NOS purge valve to release nitrous vapor from the feed line. This provides liquid nitrous to the inlet of the solenoid(s) for better consistency and repeatability. Bottle Heaters NOS systems are calibrated for optimum performance with a bottle pressure of 900-950 psi. The pressure will change with temperature Heater kits are thermostatically controlled to keep the bottle near 85 degrees F to provide correct pressure.