| Author |
Message |
Lawrence Coppari (Lawrence)
Junior Member
Username: Lawrence
Post Number: 158
Registered: 4-2002
| | Posted on Tuesday, August 13, 2002 - 5:48 am: | |
Don't let the tank get low on fuel and it'll hiss less. Hissing caused by:
1. Volume of vapor space - low on fuel means more space to pressurize until equilibrium occurs. Thus, there is more hiss until pressure reduces to atmospheric.
2. Low on fuel means fuel warms faster meaning vapor pressure rises faster. More fuel leaves the tank than is consumed by engine. Excess returns to tank nicely warmed by engine compartment trip. This raises temperature of remaining fuel in tank.
3. Can't say for sure that less fuel reaches higher steady temperature. It would be a function of cooling air flows around tank and surface area to volume ratio of tanks as they empty. |
Bill Sebestyen (Bill308)
Member
Username: Bill308
Post Number: 309
Registered: 5-2001
| | Posted on Monday, August 12, 2002 - 6:26 pm: | |
Eamon, I don't know what the vapor pressure of your gasoline is but I suspect it's pretty low, probably on the order of 1-psi. This should have little impact on your fuel system parts. The fuel supply system is supposed to be sealed for emissions reasons so is built to accomodate the low pressure. |
Eamon A Blaney (Eamon)
New member
Username: Eamon
Post Number: 11
Registered: 8-2002
| | Posted on Monday, August 12, 2002 - 9:25 am: | |
As this pressure puts a lot of strain on the tanks, crossover pipes, fuel pump gaskets etc., would it be wise to drill a 2mm vent hole in the cap itself ? |
Christian (Christiank)
Member
Username: Christiank
Post Number: 393
Registered: 1-2001
| | Posted on Monday, August 12, 2002 - 8:32 am: | |
It was discussed before and is normal. |
Eamon A Blaney (Eamon)
New member
Username: Eamon
Post Number: 7
Registered: 8-2002
| | Posted on Monday, August 12, 2002 - 8:03 am: | |
Every time I fill my gas tank there is a serious amount of hissing as the fumes escape from the tank as soon as I unscrew the petrol cap. Is this normal on a european spec Mondial ? |