Fuel bladder fitment

[Joe]

I'm finding that buying an off the shelf fuel bladder is much more economical than having a custom one made to the exact size of the enclosures that are built into the tunnels of my race car. However, the off the shelf variety are not the exact size of my enclosures.

What are the ramifications of using a bladder that is dimensionally larger by a few inches in my enclosures? By my reasoning, it would be equivalent to fitting a large size bag inside a medium size box, which is imperfect but functional, and after stuffing with foam might even be a bit safer in terms of it's resistance to rupturing in case the enclosure is damaged in a wreck. Capacity is not really an issue, I won't be doing any endurance jaunts.
What do you think?

 

[Ed]

short of an issue with incomplete emptying due to internal convolutions of the bladder, i dont see a big problem. as long as there are no significant sharp folds etc that could cause a premature bladder failure due to material stress anyways

can you point me to what bladders youve found off-the-shelf that are close in size?

cheers
ed

 

[Randy V]

I think that the bladder would be strongest fully filled out and using the support structure of the can/sill.

I don't think you'll be able to know that the "wrinkles" in the bladder would not be moving and chaffing inside the can/sill thereby causing a weak spot and potentially wearing through to the point of leaking.

I did see a number of aircraft fuel bladders some time back that were relatively close to the size of the sills on a GT40 - however - they were not certified by anyone other than the FAA and the filler inlets were not on the ends where I needed them..

 

[Joe]

Randy you're right and I'm going with something correct. No sense in experimenting with this important system of the little beast. I haven't skimped on this car yet and I don't intend to start with the fuel cell. I was going to do both fuel cells (one in left tunnel and one in right) but I think that one in the left hand tunnel opposite the driver will be sufficient. I can add one driver side in the future if necessary.

Ed, here are sources I've found so far listed below. Also try ebay (U.S) and there is a dizzying amount of fuel cells. Some look more trust worthy than others, but there is a wide variety from all manufacturers. It seems the more "square" the dimensions, the more common and inexpensive they are. I envision these are trunk mount types, where space and contour/shape are not critical.

http://www.jazproducts.com/auto_fuel_cells.html

http://www.harmonracingcells.com/index.html

http://www.fuelsafe.com/

http://atlfuelcells.com/

http://www.rciracing.com/

If someone has some other sources of fuel cells, feel free to post.