12.4 Fuel Filler Neck
Fuel filler restrictor must remain in the stock location. The steel spring loaded flapper door may be
removed.

I'm considering installing a fuel cell. I'm wondering why we need the stock fuel filler in place? What performance advantage could be gained by someone who had otherwise?
I could see if refuelling mid race was involved.

Could any filler be allowed as long as it was a set diameter and gravity fill only?

It would seem that this needs to be thought about because of the fuel cell issue. I can not imagine using the stock filler with a fuel cell. I am not even sure how it would be able to be attached to a fuel cell.

Is there any issue if someone was wanting to run the enduro series with a fuel cell and a "non-stock" filler neck of some kind?

If not, it would seem that a stock filler should not be required with a fuel cell.

Big Dog.

I don't think this is an issue if you put in a fuel cell. This is the 944 Spec rule about fuel cells:

12.6.1 The stock fuel tank may be replaced with a fuel cell(s) conforming to the NASA CCR’s,
located in the rear of the car no farther forward than the forward edge of the stock tank. The
maximum capacity of the fuel cell system is 21.1 gallons.

This is the CCR:

15.4 Fuel Cell / Tank
As of January 1, 2009 no new logbooks will be issued for vehicles with a fuel cell, unless the fuel cell is FIA FT3 (or higher) certified. As of January 1, 2012 all fuel cells must be FIA FT3 (or higher) certified, regardless of the date of purchase or date of the logbook issuance.
A fuel cell is not required, except as specified by class rules. It is recommended for all NASA classes, unless specifically listed otherwise. All vehicles having a fuel cell MUST comply with the rules in this section, even if a fuel cell is not required.

• There must be a solid metal bulkhead completely separating the fuel tank, fuel pump, fuel cell, filler neck hoses, and/or vent lines, from the driver compartment

Thanks, Steve.

This seems to indicate that any filler is OK.

I guess it helps to read the damn rules. That gives all you other guys a real advantage over the likes of me.

Big Dog

Currently a stock filler neck is required even with a fuel cell.

Why rules say a stock filler neck is required and there is nothing in the Fuel Cell rules either NASA CCR or 944 spec that takes away that limitation.

OK, so here is my question on this issue.

Why require a stock filler at all? Why allow the flapper door to be removed but require that the restrictor be left in?

How is any of that a "performance issue" for 944-Spec racing?????

It seems to me that if a guy wants to run the enduro series, he is at a real disadvantage with this rule and if he only runs 944-Spec races (which are sprint races), it is NOT a "performance issue" so why have this rule at all?

From my perspective, it makes NO sense to require a stock filler with a fuel cell and seems to make no sense for any car. I just pulled my tank and neck. It is a maze of tubes and smog/vapor stuff as well as the unledded restrictor. Again, WHY force us to retain that. Not a cost issue and NOT a performance issue but may be a safety issue with all the stuff on a stock filler neck.

Big Dog