Fuel Tank Venting

This is a topic that I haven't been satisfied with for some time. When building a track car it's pretty common to delete the emissions equipment and this often includes some vacuum switching valves and charcoal canisters.

What's left behind is usually some hoses leaking fuel vapors..

Now obviously deleting the charcoal canister you will have vapors escaping no matter what, but what is the most motorsport appropriate approach to solving fuel tank venting?

In the past I have just put a check valve on the vent hose, and routed to the back of the car.

What do the rules require? SCCA fuel cell rules require no leaking when inverted. Either a check valve (allowing air into a cell, but preventing fluid from leaving), or a 540 degree loop of hose going around the cell and connecting to the vent port (which prevents a siphon) are typical solutions.

Here are some specific wording found in the SCCA GCR for using OEM gas tanks, other rules for different classes:

Factory installed gas tank evaporative emission control devices must be removed from all Production and GT

Category cars. Fuel cell vents must not discharge into the driver/passenger compartments, even if installed

that way by the manufacturer. The fuel system cannot vent through the roll bar/roll cage structure

...

Fuel cell vents shall be located at least 25cm (9.84 inches) to the rear of the cockpit.

...

A safety fuel cell complying with GCR Section 9.3 Fuel Cell Specifications, shall be installed. All fuel cell

vents shall incorporate check valves to prevent fuel spillage. Dry‑break refueling couplings and discriminator

valves may be installed, provided they do not extend beyond the bodywork. The use of a fuel cell is required

unless the stock fuel tank is located between the axle centerlines and within the main chassis structure

(e.g. frame rails). Spec line allowances will be added on a case by case basis.

Sounds like I have largely been following best practices. Thank you David