Gas Tank - vent

[Sevey]

i noticed these gas tanks create pressure while running. When you unscrew the cap you can always hear the pressure release. Figured vent line was blocked, vapour lock or something.

I put pressure on the gas tank by blowing into it and thought the air would immediately be released out the vent line but it seems it is valved and only blows off under quite a bit of pressure

Why did they design it like this? Surprised the fuel pump doesn’t have issues.
Ms

 

[Turboflash]

EPA regulations. Same reason the fuel system in your car isn't vented to atmosphere. The pressure in the fuel tank actually helps the fuel pump because it's trying to push fuel out of tank through the fuel line.

 

[KnappAttack]

i noticed these gas tanks create pressure while running. When you unscrew the cap you can always hear the pressure release. Figured vent line was blocked, vapour lock or something.

I put pressure on the gas tank by blowing into it and thought the air would immediately be released out the vent line but it seems it is valved and only blows off under quite a bit of pressure

Why did they design it like this? Surprised the fuel pump doesn’t have issues.
Ms

Designed like this to hold the fuel vapors and not let them escape into the air. The pressure build up in the tank should hold, or is designed to be about 3 lbs, above that it vents. Its a good thing actually, fuel under pressure holds the light ends in and keeps its freshness longer. Pressure venting can sound like a squealing sound that many hear and question.

If anything pressure will make it easier for the fuel pump.

Gas that does not make pressure has gone stale. It's called reid vapor pressure, and if its not there, its stale fuel that does not like to light off easily. https://www.epa.gov/gasoline-standards/gasoline-reid-vapor-pressure https://www.pei.org/wiki/reid-vapor-pressure

 

[Sevey]

Interesting

The nytro vent just dumped along the left footwell. You knew the tank was full when you heard the gas dripping on the ground

You also knew you trailered too fast , when upon arrival and opening the door and smelling gas . Lol
Ms