removing charcoal canister?

[puma]

If i wanted to remove the emission system completly and take out the charcoal canister and the pump module, what woud you do after? Do i just plug the unused lines at the tank? Should the tank be vented so it doesn't pressurize? Would the tank pressurize or become in a vacuum when the level lowers?


thanks for any insight and in case you are wondering it is to build a race car and we are faily new at this. We don't want to use a fuel cell yet.

[350matt]

The fuel filler cap has a 1 way valve in it to allow air in to prevent a vacuum

but yes the purge system vents tank pressure into the engine inlet so prevents it building up on a hot day which can be dangerous

so just blanking off the tank vents probably isn't a good idea

in the days before purge systems the tank was vented through a charcoal cannister and out to atomosphere under the car

and before the days of charcoal cannisters the tank was just vented and breathed through the cap

[puma]

just checked the manual, there is a cut off valve on top of the tank with the vent, anyone knows exactly how it works, the drawing is weird and the way it is done on top, i have a hard time figuring out how the cut off valve will prevent fuel to come down that tube in case of a roll over.

[Poodles]

It's a bit more complex than that, but are you going with a fuel cell and that's why you're getting rid of it? If not, there's no reason to even mess with the system.


Gas cap has a one way check valve, and the valve that vents to the CC canister usually has a 2psi or so spring in it. Once the engine is up to operating temp, it starts to take the vapor from the tank into the motor (charcoal will both absorb and release the vapors). Keep in mind the pressures (fully closed off system is going to cause odd fuel pressures, and the 2psi helps prevent cavitation of the fuel pump).

[humfrz]

Originally Posted by 350matt

............

in the days before purge systems the tank was vented through a charcoal cannister and out to atomosphere under the car

and before the days of charcoal cannisters the tank was just vented and breathed through the cap

......and before that ..... the horse just farted ......

(yes, I know .... time fer ma meds .... )


humfrz

[puma]

Originally Posted by Poodles

It's a bit more complex than that, but are you going with a fuel cell and that's why you're getting rid of it? If not, there's no reason to even mess with the system.


Gas cap has a one way check valve, and the valve that vents to the CC canister usually has a 2psi or so spring in it. Once the engine is up to operating temp, it starts to take the vapor from the tank into the motor (charcoal will both absorb and release the vapors). Keep in mind the pressures (fully closed off system is going to cause odd fuel pressures, and the 2psi helps prevent cavitation of the fuel pump).

i am not going with a fuel cell for the moment, i want to get rid of it because i want to remove as much weight as possible and make the system as simple as can be.

i beleive that from the look of it, i can just remove everything and leave the line unplugged so that the tank will vent itself. There seem to be a one way valve on top that would prevent fuel leakage in case of a roll over.

I have a spare tank on hand, i will do some testings.

[arghx7]

I've deleted charcoal canisters and vented evap lines on older cars. It had a noticeable smell on a hot day when the fuel heats up, kind of like an open vent on a gas can for a lawn mower. This was a return PFI fuel system. Your experience may vary.

[Poodles]

Originally Posted by puma

i am not going with a fuel cell for the moment, i want to get rid of it because i want to remove as much weight as possible and make the system as simple as can be.

i beleive that from the look of it, i can just remove everything and leave the line unplugged so that the tank will vent itself. There seem to be a one way valve on top that would prevent fuel leakage in case of a roll over.

I have a spare tank on hand, i will do some testings.

Components of the system are light, and removal would cause an MIL. Last time I messed with a modern system like this the components weighed less than a healthy #2...


I'd like personally look elsewhere to lighten things up.

[stugray]

1 - You are so serious about building a racecar that you want to shed a couple of extra pounds that are fairly important to the operation of the system and makes the vehicle less safe.

2 - You are not serious enough about racing that you dismiss the need for a real fuel cell.

Those two statements seem self-contradictory.

My vintage racecar has a fuel cell that cost all of about $350..

[puma]

For those who actually care, i ended up doing some test with a spare tank we have and filled it up with water. We removed all the charcoal canister and pump lines and turned the tank upside down to see if we would get a leak through the vent line. We didn't get a single drop so the cut off valve really does it's job. To make sure we didn't get any fuel vapor coming inside the cabin we used the vent line that goes near the gas cap and connected both together. We are also eliminating the line that went to the front of the car.

here is a pic for further reference if someone ever has the need to do something like this.

[Poodles]

If you attached the vent line that goes to the gas cap (which is actually behind the cap and is used for vapor recovery while fueling) to the actual vent line, you've sealed the tank...making essentially a bomb.

[puma]

no it is the line that goes to the fuel filler but isn't going inside the fuel cap, just under, i beleive originally it is the line to bring air in the tank when it goes in vacuum.

the one you are talking about is like 1/4

here is the diagram, i beleive it is the line between #8 (air filter) and the gas door

[puma]

just went in the garage and took a pic, here is where the line ends up

[stugray]

Sorry to be a PITA, but if you are willing to sacrifice safety for a few hundred $$, then you cannot afford a real racecar.

A real fuel cell will cost about as much as a good set of tires, or are you planning on not buying tires either?