Aux fuel tank on track day tire trailer

Hi folks, I'm in the process of refurbishing my 48x96 HF trailer that serves double duty as a home utility trailer and a track day trailer to haul tires, tools, fuel, jack, cooler, the usual. 

During my last few track events in my stockish E92 M3 I found myself needing to refuel throughout the day to ensure fuel stayed above 1/4-1/2 to prevent fuel starvation. Never actually had any starvation issues, but still want to avoid it. 

I found myself needing to leave the track during precious rest periods or lunch hours to find a gas station and refuel. During these times I found myself wishing I could sit down and relax, rehydrate, check tire pressures, review data, socialize with instructor and other drivers, etc. It's also annoying dragging around multiple 5 gal gas cans that I have to bring in the car to fill up at lunch and hope it doesn't spill or stink up the car. 

Last night while dreaming about warmer weather I thought up the crazy idea of installing a smallish fuel cell on the front of the trailer tongue area, behind the toolbox but in front of the actual cargo area. 

Old photo of said trailer:

Here's where I'm thinking of sticking the cell. Toolbox would have to move forward slightly to allow a stake side to be installed in the front as I still use this trailer for firewood, plywood and lumber, etc. 

I'm thinking a 15 gallon aluminum cell with a top fill that can be easily filled with 93 while refueling the car. For some reason this one is advertised at a 17 gallon but running the volume calc I only get 15.

I would need to have a -8AN bung welded on other the side at the bottom, or on the actual bottom of the tank. The idea would be to have a separate small 5 gal gas can that you can fill as needed from the trailer and then refill the car. Doesn't make filling the car any easier but you don't have to leave the track grounds. 

In terms of safety, I'd need a secure mounting system, a relief valve to let it breathe for temperature differentials, and a shutoff valve at the "drain" that can stand up to gasoline. 

Thoughts? Am I crazy? Too much egg nog?

Why not a truck bed transfer tank?  They've already got the mounting tabs, vents needed (yes, you need a vent), etc. Plus hoses, pumps, etc are all available with standard fittings to connect. 
 

Why reinvent the wheel?

Yep. Replace the existing box with this. Hauls fuel and tools and is DOT rated. 

^^ Those are great and would fit the bill nicely but I am not sure I can justify $1500 on a tank/toolbox. Capacity also seems to be gigantic, didn't see any smaller than 37 gallons. That's also adding a ton of tongue weight. Is there a 15-20 gal option? 

Here's a 15 gal transfer tank that is DOT approved which includes a fueling nozzle and all the fittings and hoses for under $200

15 gal transfer tank

You mention having the 5 gallon cans in the car. Why can't you strap them to the trailer and fill them up on the way to the event? I'm all for over engineering a problem, but sometimes the solution is 2-3 gas cans and a ratchet strap. Cheap, easy, and removable when you need the trailer for yard work.

I've thought about similar for my car trailer, but I keep coming back to keep it simple.

The more I think about it the more I realize that a stationary tank on the trailer doesn't really gain me all that much. It prevents me from going back to the gas station but it still requires me to fill up a 5 gal can, when then is used to fill up the car, adding unnecessary steps. I think I'm going to stock up on the popular race style 5 gallon jugs and just fill them on the way to the event. 

nsogiba said:

The more I think about it the more I realize that a stationary tank on the trailer doesn't really gain me all that much. It prevents me from going back to the gas station but it still requires me to fill up a 5 gal can, when then is used to fill up the car, adding unnecessary steps. I think I'm going to stock up on the popular race style 5 gallon jugs and just fill them on the way to the event. 

You can get tanks with pumps and filler nozzles on then, but then that's driving the price up even more.  Putting one in the pickup bed of your tow vehicle is the best way to go, if you've got one.  Putting one in the trailer just means you need to take the trailer to the gas station, which is always a pain.

I agree that strapping a half dozen 5 gallon jugs on the trailer is the simplest solution.

A 14 gallon flow and go rolling tank comes complete with a hose and nozzle. 

They're intended for fueling boats, so the hose might be gravity fed. 
Northern Tool