glbrighenti

Hi everyone, I need some advice regarding the gas tank vent/evap system.

I bought this used spec car in the beginning of the year, and when I did I noticed this, which back then I thought was a fuel pump out, but I had no idea how it worked. I was not planning on using it so I didn't care at the time.




Today, I decided to chase it, to see how it works, it turns out it's just a hose (in blue) connected to the vent of the gas tank.



1- What is this? I don't think it can be used as a fuel pump out even if put under vacuum. Anyone have any idea what was the intent here?

2- Is this safe? Because this is clearly venting the gas tank into the frunk. I thought about reconnecting to the original charcoal canister, but that's gone (also gone is the connecting hose, and those valves that sit near the gas filler neck). Pretty sure it will be very expensive to redo the whole front part of the evap system.

3- Since this is a spec car, I don't think I need a full evap system, since this car is not road legal, but I am trying to find a solution that makes it safe. I thought about simply putting a plug in this thing, but then there will be no venting for the tank, which probably is not a good idea.

Any comments are appreciated.

cscowden

It is likely a vent for the gas tank to improve the fill rate of gas going into the tank during a pit stop. We've had to do this on several endurance race cars to be able to accept faster fuel dumps during pit stops. The Boxster is notoriously slow to accept fuel and forces you to fill and wait. The vent allows you to just dump the fuel can upside down and fill the tank rapidly.

glbrighenti

Thanks, that makes sense.

Isn't it unsafe to have gas venting to the frunk? Should I do anything about it?

KevinA

I have a quick filler on my SPB that uses dump cans. I can dump a 5 gallon can in about 12-15 seconds. It uses a special fitting that I have to put on the cans. The car came with this, and it can be somewhat of a pain since I have to screw the fitting on each can individually.
There is a rubber hose that vents from the tank through the frunk and through a hole in the floor of the frunk. I think it was a hole that was originally in the car, but had a plastic/rubber fitting that was popped out for this purpose.
I have a zip tie on the end that sticks through the bottom of the frunk so the hose does not come loose.
I would NOT let gas vent into an enclosed space like the frunk. I'm no chemist, but recall reading that gasoline vapors ignite easier than gasoline in liquid form. One spark, and kablammo......
If I were you, I would attach a hose to the end of the red fitting.
If you look really close at the photo of my car, you can see the tube sticking down.

Nickshu

Not sure this helps as it doesn't sound like you are building an endurance car, but I have a quick dump system in my SPB and I built this vent into the stock tank using a fuel cell vent. I had help from @turbochad in building it, getting the clearance to the hood takes just the right parts and some modification of the vent valve. Before this my car had a similar vent like yours but it went to an electronic valve that would open when filling with fuel, and it did not work very well. This works much better. I use my car for SPB racing in PCA, but originally it was build for WRL endurance racing. I installed this with the fuel tank removed from the car.

glbrighenti

Exactly, that was my concern. I guess I`ll attach a tube to the floor like you, or maybe go back and up instead and put it close to the bottom of windshield. I saw some a opening where the windshield wiper used to be.

Now, since I don't need fast refueling, what if I put a plug in this vent? In normal operation the vent is blocked, but when I want to refuel I just open that. Would that affect fuel flow during operation?