Tank venting through charcoal canister?

liam66 Officially Full-On Dubber

260 posts · joined Oct 2005 · 19 Nov 2010, 3:31 pm

#813347

Rather than much about with swirl pots and stuff, I've modified a std tank to accept a subaru pump assembly.
This assembly has 3 lines, fuel supply, fuel return and a line to the charcoal canister and is hooked up just like a stocker.
The standard vw tank came with a small breather line off the top ( opposite side to the filler and fill vent.) I have this vented to atmosphere at the moment. Seems to be a high amount of venting going on...When the tank is full, starting the car causes fuel to come out the vent hose.
I dont believe the filler cap is vented.

Question is; Should there be a vent on the tank or does the subaru setup just vent through a charcoal canister?

(yes, the tank was cleaned before chopping and welding)

liam66 Officially Full-On Dubber

260 posts · joined Oct 2005 · 19 Nov 2010, 6:26 pm

#813387

Thinking of just tee-ing the vw line into the subauru line to the charcoal canister?

Joel Now containing 100\% E-Wang

9,368 posts · joined Feb 2006 · 19 Nov 2010, 8:06 pm

#813409

Nice work on the flange, I was gonna go this way but installing baffles in the tank to stop fuel surge was more effort than I could be arsed with.

Have you got enough height on the breather hose?

Normally they come off the filler and have a tee up fairly high that runs off to a vent hose either open to atmo or into a charcoal canister

liam66 Officially Full-On Dubber

260 posts · joined Oct 2005 · 26 Dec 2010, 8:41 pm

#818444

I tried blocking the tank breather, so 100% of the venting would be through the charcoal canister... Result was a loss in performance, positively pressurized tank and raw fuel coming out the bottom of the charcoal canister.
Is there meant to be a one way valve on the line ?