turbogrill Posted July 1, 2021 Report Share Posted July 1, 2021 Hi, Do modern cars (2006+ Miata) still have a negative pressure valve in the gas caps? The intention would be to avoid excessive vacuum in the tank (that could destroy the tank or make the pump struggle). Over pressure is handled by the EVAP I believe. Am I asking for trouble If I replace my 100% stock fuel system with an after market filler tube and cap ? (Still has venting for fueling and overpressure venting via EVAP) Quote Link to comment Share on other sites More sharing options...
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