Engineer/math minds - Fuel tank HELP!!

[BlownV6]

Ok guys I need more help!! Im moving the fuel tank into the very front of my dragster (currently behind the seat) to put more weight on the nose to help keep the front wheels down. This way I can be more aggressive with the power applied early and hopefully make it go quicker!! I currently use a 10.6 GPM pump and will be sending it back to upgrade it to a 12.6 GPM. I am installing #16AN fittings and 7/8 ID pipe back to the engine/pump.

Ok the question is what size vent tube will this require?? I need this to be at the minimum size required because as you can see the location of the tank is going to pose some issues with venting as far as spillage while doing a burnout - stopping to backup - leaving the starting line etc. My thinking is to keep it at the minimum size required to keep a constant negative draw on it to avoid splilling fuel!! But needs to big enough to keep any vacuum from being created in the tank while under full throttle!! Anyone have thoughs on this!!
Thanks Mike

 

[S10xGN]

Do you have a datalogger? If so, put a vacuum sensor on the tank and start out small, increasing the size until you get no drop. Air's "viscosity" is so much lower than fuel, IMO you could prolly get away with a 1/4" - 3/8" hole.

 

[Alky V6]

The best vent design I've seen is a vent tube running on top of the cell running from the front to the rear. The tube bends down at each end and connects to the front and rear of the cell. In the middle of this vent tube, which should be at the middle of the fuel cell, another tube Tee's into this tube and makes a large radius bend towards the front of the fuel cell. The end of this tube then is open at the front of the cell to pick up positive air pressure that might build up at the front surface of the cell during forward acceleration. An inline filter can be installed into the T line to help keep contamination out of the fuel cell, and also help arrest fuel that may try to escape from the vent.
The bigger the vent tube size the better. 3/8" should be a minimum for what you will be doing.

Other tips. The fuel cell should be mounted as close to the pump as possible to prevent cavitation at the inlet of the pump.
Fine screen filters should not be used at the fuel pump inlet. Again, to prevent cavitation at the pump inlet. Instead, strain the fuel as it is being poured into the fuel cell.
Intall your inline filter after the pump and before the barrel valve.