I would like to open a discussion on these very topics. I became interested in them as I began setting up my tanks. I am trying to setup a system of linking the tanks and using only one set of pumps. My first problem arose when I had the system that I thought would work, to find that fuel being pumped into my reserve tank(the one without the pumps), was filling faster than it was being shunted back to the primary tank, and fuel began shooting out of the vents on the front of the tank.
Well I think I have solved the problem, but it got me to thinking that I needed a system that would protect me and all the owners of GT-40s from the buildup of pressure in the tanks. Scenarios range from parking on hills to rapid deceleration, rapid acceleration, and heavy cornering. For those of you with the selector valves, how about one of them getting stuck or gumed up causing the fuel to go where you don't want it, say,, all to just one tank!!
The easy answer to this is vents in the front and rear of the tanks. The part it doesn't answer is the safety of using them and what type. One answer is to install a rollover valve which allows you to keep from spilling gas in the event of a rollover, and it allows for the free flow of air into and out of the tank. The problems with this is it allows the free flow of gas vapors out of these lines as the gas is heated(sitting in the sun) or gas is sloshed around in the tank under the scenarios outlined above, as well as when you fill the tank at your neighborhood gas station, or the stuck valve scenario. Some of the rollover valves are large and won't stop the flow of gas up the line and into the front or rear clip area in an upright car.
It was mentioned on another thread that the individual posting didn't like fuel near electrical devices or electricity. Lets look at the various vents in these cars. The front vents are usually mounted near the fuel filler caps. Well if you mount your battery in the front as mine is, the vapors will sink down into the front clip area as well as out the sides, and near the fresh air intakes on some of our cars, which leads to gas vapors entering the cabin. Not good. Vapors around the battery and other electrical appliances could lead to bad experiences.
In the rear the same thing happens except it is behind you and probably few if any vapors get into the cabin, but all do go into the rear clip area. What do we have there, but hot exhaust and electrical appliances again.
Most modern cars have rollover valves built into them now. The outflow of these lines usually goes to a Charcoal canister to absorb the fuel vapors. On most of these fuel tanks, there are one or two, fuel vapor valves as well as a vent line up the fuel filler line to help prevent air pockets from forming and not filling the tank. These valves are small valves that will stop the sloshing of the fuel up into these vent lines that lead to the antirollover valve, which leads to the charcoal cannister. Some are built together as one piece.
I don't think I have seen one GT-40 that utilizes a fuel vapor valve that prevents the sloshing up into the vent lines or a charcoal canister(could be wrong on this one). Just the rollover valves. Most of the space frame cars and probably some of the monocoques have the room for the canisters in the front besides the filler tubes where they wouldn't be seen, so that doesn't seem to be an issue except there would be little hoses running all around the car, or lots of little canisters stashed all about the car.
So other than from an environmental issue of fuel vapors to the atmosphere, why don't we use the vapor valves and the carbon canisters? Just because our cars may be exempt from emissions doesn't mean we shouldn't think about it.
I for one plan to use the vapor valves if nothing else than to keep the fuel from sloshing up into the vent lines(as they have once). I will also use the rollover valves. I am undecided about the canisters since mine is not on the road yet.
What are your thoughts on this topic(s). Am I just blowing hot air up your skirts over nothing or is it a concern that we should address in our builds?? Are the vapors so small they aren't a concern??What do you think??
Bill
Well I think I have solved the problem, but it got me to thinking that I needed a system that would protect me and all the owners of GT-40s from the buildup of pressure in the tanks. Scenarios range from parking on hills to rapid deceleration, rapid acceleration, and heavy cornering. For those of you with the selector valves, how about one of them getting stuck or gumed up causing the fuel to go where you don't want it, say,, all to just one tank!!
The easy answer to this is vents in the front and rear of the tanks. The part it doesn't answer is the safety of using them and what type. One answer is to install a rollover valve which allows you to keep from spilling gas in the event of a rollover, and it allows for the free flow of air into and out of the tank. The problems with this is it allows the free flow of gas vapors out of these lines as the gas is heated(sitting in the sun) or gas is sloshed around in the tank under the scenarios outlined above, as well as when you fill the tank at your neighborhood gas station, or the stuck valve scenario. Some of the rollover valves are large and won't stop the flow of gas up the line and into the front or rear clip area in an upright car.
It was mentioned on another thread that the individual posting didn't like fuel near electrical devices or electricity. Lets look at the various vents in these cars. The front vents are usually mounted near the fuel filler caps. Well if you mount your battery in the front as mine is, the vapors will sink down into the front clip area as well as out the sides, and near the fresh air intakes on some of our cars, which leads to gas vapors entering the cabin. Not good. Vapors around the battery and other electrical appliances could lead to bad experiences.
In the rear the same thing happens except it is behind you and probably few if any vapors get into the cabin, but all do go into the rear clip area. What do we have there, but hot exhaust and electrical appliances again.
Most modern cars have rollover valves built into them now. The outflow of these lines usually goes to a Charcoal canister to absorb the fuel vapors. On most of these fuel tanks, there are one or two, fuel vapor valves as well as a vent line up the fuel filler line to help prevent air pockets from forming and not filling the tank. These valves are small valves that will stop the sloshing of the fuel up into these vent lines that lead to the antirollover valve, which leads to the charcoal cannister. Some are built together as one piece.
I don't think I have seen one GT-40 that utilizes a fuel vapor valve that prevents the sloshing up into the vent lines or a charcoal canister(could be wrong on this one). Just the rollover valves. Most of the space frame cars and probably some of the monocoques have the room for the canisters in the front besides the filler tubes where they wouldn't be seen, so that doesn't seem to be an issue except there would be little hoses running all around the car, or lots of little canisters stashed all about the car.
So other than from an environmental issue of fuel vapors to the atmosphere, why don't we use the vapor valves and the carbon canisters? Just because our cars may be exempt from emissions doesn't mean we shouldn't think about it.
I for one plan to use the vapor valves if nothing else than to keep the fuel from sloshing up into the vent lines(as they have once). I will also use the rollover valves. I am undecided about the canisters since mine is not on the road yet.
What are your thoughts on this topic(s). Am I just blowing hot air up your skirts over nothing or is it a concern that we should address in our builds?? Are the vapors so small they aren't a concern??What do you think??
Bill