fuel cell rules for ST2

[NotoriousJJE]

Hi all, this is my first post here. I am currently building a car for ST2 and I have a question pertaining to the rules on fuel cells.

 

My plan is to purchase a fuel cell that will sit within 12" of the original location. I was also thinking of cutting out the spare tire well in the trunk to aid in the installation of the cell. The question is, do I need to cover the fuel cell with a metal bulkhead even though it will sit in the trunk(car is a hatchback) and below the floor level? Or more specifically, will the metal on the cell itself (ATL) suffice as a bulkhead? If not, is a thin piece of aluminum considered sufficient?

 

Thanks

 

jero

 

ps- I know the rules state "There must be a solid metal bulkhead..."

 

[Frank Corkran]

The complete rule states:

 

"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."

 

The "trunk" in a hatchback (and most sedans as well, once you remove the plastic/fabric interior bits) is open to and therefore part of the "driver compartment". The cell (or fuel tank) itself, including the filler neck and fuel and vent outlets - not just the bladder - must be separated from that compartment. So yes, you will need a metal bulkhead either completely covering the cell or completely separating the cell area from the driver area. This is needed in many older Fords even when using the stock tank, because the top of the tank IS the trunk floor. If you mount the cell below floor level, then you could use a flat plate above it. If the cell is flush or above (the filler and outlets at least would protrude above the floor), then you'd need to make a "doghouse". Either would need a door to allow fueling, unless you use a remote fill port - and that would require another metal structure covering the hose out to the edge of the body. If you want to pass the vent and/or fuel lines through the cabin you'd need to use bulkead fittings and metal lines. Of course you don't need to worry about fill/vent hoses in back if you build a bulkhead completely separating the "trunk area" from the forward cockpit. That always seemed iffy to me for hatchbacks since it relies on the hatch remaining closed tightly. I know of at least one STU hatch that flies open every time the car spins. Which it seems to do numerous times in each race.

 

Aluminum is fine for a bulkhead, but you want it thick enough so that it won't melt instantly in a gasoline fire. I've heard thicknesses of .065" or better mentioned elsewhere for aluminum bulkeads if you want them to function as any sort of firewall, but I've never seen a hard spec on that. And I've seen thinner aluminum bulkeads.

 

Never having owned a plastic car, it suddenly occurs to me that you would need to build a sealed box around the cell to truly separate it from the driver compartment with a metal bulkhead in a Corvette - because the body and floorpan aren't metal. I'm guessing that probably isn't required to pass tech.

 

Of course your best bet is to contact the Chief of Tech for your region before you start fabricating.

[NotoriousJJE]

Thanks man I appreciate the help.

 

Looking forward to finishing this thing and mixing it up with you guys soon.

 

jero