hot gas tank
 

I just drove sc1 on a 208 mile trip in 90 degree weather. I have a full belly pan under the car. When I went to fill up, just getting off the interstate the gas tank was under pressure. Fumes continued to vent for a while I think the gas inside was boiling. I need to put some cooling air around it and some foil around the exhaust pipe, scary. Boiling point is listed as 100F to 400F WTF is that suppose to mean.

does not sound good to me, wonder how hot it is getting in that ?enclosed ? space
on a hot day all those sealed fuel systems will build vapor . i forget the vapor pressure of fuel but its not so high
hot gasoline , humm one hopes there is a pressure relief that will vent it before the tank ruptures

foil would be ineffective as heat shield.. some of these products would be effective
https://www.pegasusautoracing.com/gr...pID=HEADERWRAP

https://www.pegasusautoracing.com/Images/S/1835-070.GIF
This short 15 foot roll will cover a single 1.5" diameter pipe about 38" long, or a 2" diameter pipe about 28" long. It's also a great size to keep around for emergencies.

https://www.pegasusautoracing.com/gr...ID=HEATBARRIER
https://www.pegasusautoracing.com/images/M/1828.JPG
Adhesive Backed Aluminized Heat Barrier Cloth can be used to protect composite engine cowls, hoses, wires, painted surfaces, or any component that may be subject to damaging radiant heat. The Heat Barrier is made of woven silica with a flexible aluminized finish. The highly reflective surface of the material is capable of withstanding radiant temperatures in excess of 2000°F.

wrap the pipes adjacent .. apply the barrier cloth to the tank adjacent to the pipes

cooling air ..

set one of these ducts in the belly pan , put air ducting hose on it .if required
https://www.pegasusautoracing.com/pr...p?Product=3627
https://www.pegasusautoracing.com/Im.../3627-PLUS.JPG

good luck

If your gas tank really is getting that hot then paint it with zinc oxide paint, it allows heat to radiate out but also reflects heat away, that is why it's used to make white roofs that stay cool in the sun.

Return fuel systems absorb heat from the engine compartment. The longer you drive the hotter the tank gets as the fuel absorbs more and more heat. If you are using a belly pan, you need to provide some means for the air to circulate over the tank for cooling. You also need to make sure the exhaust system heat is not allowed to heat up the tank.

On hot days you can also get heat from the pavement, especially ashphalt, which can get very hot in direct sunlight, probably over 200 degrees if there is little wind.

The fuel tank in return systems is like a radiator. Some airflow is necessary for proper cooling. You will neve see a properly working fuel tank with vapor recovery reach a dangerous pressure point, unless you remove all potential cooling and add other heat sources like the exhaust system. If you had this happen the charcoal cannister would be overwhelmed with fuel vapors and you would smell fuel when you stopped. You would probably also get a check engine light indicating a vapor recovery problem.

regards
Mech

I've has a belly pan on my cars for 8 years and this is the first time it's happened. Combination of high ambient and long trip. Maybe it was the cheap Mobil gas, since it didn't do it when I filled up in Roscoe, but did when I returned home. I did have the AC on driving there, maybe the radiator fan was enough to cool the gas.

I know this was an old thread, but was your cap venting? YOu should be able to blow through it. There is supposed to be a small spring valve that releases excess pressure no?