[U4IA187]

Last weekend I did a heavy track day at sebring. No problem with my exige - although an elise caught on fire. However, upon refilling my car the attendant an myself notied that the gas was bubbling as if it were boiling after being filled.

anythoughts? Warnings? Anything I need to do differently or avoid? I really dont want to set mycar on fire.

 

[Cthulhu]

The boiling point of gasoline is around 400 deg F, or 205 deg C. That BP would be for high octane (i assume you're running 93) gasoline. It seems like a hot exhaust could definately achieve such a temperature.

Also, boiling points are pressure dependent (PV = nRT, where P is pressure, V is volume, n is number of moles, R is the gas constant, and T is kelvin temperature). Your tank is pressure sealed to keep vapors from pouring out, primarily for environmental and safety reasons. If your ECU detects a pressure drop (try opening your gas cap with the car idling for a while) it will turn the CEL light on and mess with fuel settings to compensate.

If your tank is pressurized and heated it may not boil, but when you open the tank, the pressure drops and it boils in a frenzy to lower the temperature of the gas. It's kinda intuitive that this is dangerous as all hell, things could catch fire, explode, etc.

Look for threads about tracking your car and exhaust heat. I saw one a while ago about the insulation around the stock exhaust causing things to get insanely hot, and loosening screws. I think someone mentioned something about using ceramic as a heat shield around the pipes or something, but you should look into this. The op posted it as WARNING: blah blah exhaust blah...

Edit:
here it is: http://www.lotustalk.com/forums/f154/warning-track-guys-check-your-exhaust-systems-58233/

 

[Bgwilly31]

Whoa!

I probably would have ran..anic:

 

[Cthulhu]

I would have calmy smoked a cigarette...

 

[U4IA187]

I plan on opening up the bottom end of the car to check ut the exhaust system, make sure there arent any brackets loose or anything else noted n the warnig thread.

I aslo plan on giving plenty of time between track, cool down, and refueling.

Your inputs are greatly appreciated, maybe i should just sit back and calmly smoke a cigarette.

 

[def]

although an elise caught on fire.

It's amazing how many catch fire, it seems like every other week someone casually mentions another one in various parts of LT.


Also it's good to check the exhaust system. But the gas tank is kind of far from that (other side of engine)

 

[Cthulhu]

I plan on opening up the bottom end of the car to check ut the exhaust system, make sure there arent any brackets loose or anything else noted n the warnig thread.

I aslo plan on giving plenty of time between track, cool down, and refueling.

Your inputs are greatly appreciated, maybe i should just sit back and calmly smoke a cigarette.

I'm not an overly cautious person, but I can't help thinking that your situation is a lot like a can of creamed corn in a camp fire. Sure, your tank is pressurized, but who knows what pressure you're generating by heating up your gas above its STP (std. temp and pressure) boiling point. I have no idea how the pressure system works and if it can vent, if it'll blow ur gas cap off, if itl kill ur fuel pump, if it'll compromise your fuel tank, etc... Either way, I don't think your gas should ever boil, GET IT FIXED. anic:

At a bare minimum, monitor your fuel temperature, even if you have to use a dipstick thermometer every 10 minutes. Also, if your exhaust is getting that hot, you risk a fire elsewhere.

I'm not even suggesting that you spend a load of money getting people to check it out, but, for the love of god and all that is holy: find a way to monitor the temperature of your fuel and the temperature in the engine bay around the heat shields.

Without knowing your temperatures, all the tightening of bolts and fiberglass wrapping or removing is like trying to catch a bat in a cave without a headlamp.

 

[U4IA187]

I do plan on getting it fixed, although i was hoping that someone has had some experience in this and can pass tangilble information. Im afraid that if I go to the dealer and say "I have hot gas" they will just give me the stupid look. Hold onto my car for two weeks, and overcharge me for an oil change. Seriously, we've established the high operating temperatures, other than the info in the "warning" post, where else can I point my mechanics? I think we are all concerned considering the rash of car fires. thanks for any and all input.

 

[Vulcan Grey]

Don't fill your tank all the way for a track day, leave room at the top.

If you overfill, the fuel can go up into the filler neck area. Also if you don't leave room for expansion, you will overwhelm the vapor recovery system. The charcoal tank purging excess fuel might cause a fire hazard.

 

[chapster5]

I would have calmy smoked a cigarette...

rotflrotflrotfl

 

[sleepe]

you most likely heard fuel vapor escaping rapidly.

I don't think it is even possible to boil the fuel if you car is
in good working condition.

 

[U4IA187]

Don't fill your tank all the way for a track day, leave room at the top.

If you overfill, the fuel can go up into the filler neck area. Also if you don't leave room for expansion, you will overwhelm the vapor recovery system. The charcoal tank purging excess fuel might cause a fire hazard.

I noticed the overfill hose that evacuates along the inside of the right rear quarter panel. I thought of that being alittle dangerous as well. I guess I did fill the tank completely while inbetween events, next time ill allow more room.

Also bought a fire extinguisher just in case. <<knock on wood>>

 

[Cthulhu]

I wonder if you can get a thermometer long enough to poke in there if it happens again... It would remove all doubt. It seems like it would be very possible to boil fuel, especially when you first open the cap. The B.P. of gas varies widely in range depending on octane and composition, but could be as low as 200 F. Given that other post about exhaust temperatures, and the fact that a few elises have lit up, I would check on it if it was me. I'm not saying there aren't other possibilities, but it seems like it's worth checking with a thermometer. I have not looked to see how shielded everything is in the back of the car, I've only had my front clam off, not the back.

Btw: did you actually SEE it bubbling out of the tank, big time? Was the smell of gas completely overpowering? Or did you just hear a hissing noise, like someone else suggested. I'd think if it was past the STP boiling point, you'd hear a pop or loud hiss the moment you opened the cap, and then smell lots of gas fumes and hear lots of bubbling.

 

[U4IA187]

I didnt open the gas cap, someone else did, but as soon as they mentioned the sound I went to investigate. Very clear bubbling sound.