Thanks for the update. I too had originally, by not so careful rules reading, removed the charcoal canister from my '87 16V. After everyone pointed out the error of this thinking I put it back in. Now I can officially remove it, non-trivial weight:)
What isn't explicitly clear to me about these suggested check/vent valve solutions is the mounting requirements.
http://www.summitracing.com/parts/abt-tf350
http://m.summitracing.com/parts/sum-220020
http://www.fuelsafe.com/store/vent-c...lves/rv38.html
Assuming that most cars are generally the same, some kind of plastic vent line from the tank to the charcoal/carbon canister, and the carbon canister can be packaged in any orientation, as can the hose between the fuel tank and canister, what are the installation requirements for these devices so they function correctly? Do the first two have to be installed vertically to function correctly? The Fuel Safe Vent Check Valve can be installed in any orientation, but it may not be advisable to install it in the engine compartment if that was where the OEM charcoal canister was mounted, since venting fuel vapors underhood might not be such a good idea......