Posted By: jbc426
Fuel tank mods to improve fuel scavaging. - 02/13/17 04:57 AM
I am running a larger than stock stainless tank I designed and had built by Rick's Tanks a few years ago. It holds just shy of 30 gallons and fits in the stock location. It had used a -12AN tube to suck fuel out of the tank and there are internal baffles to control fuel slosh while driving.
The problem I had was that my fuel pump would create a vortex in the fuel and start sucking air once the tank got below 3/4 full. Its essentially the same effect when you drain your bath tube. This caused the pump to work harder and cavitate. It took me a while to figure out what was going on.
I thought about how to have a street friendly fuel system that would be able to use most of the fuel in the tank without sucking air. Especially during hard launches and cornering. I initially looked at baffled fuel traps like they use in road course cars, and then looked at snowmobile style pick-ups in all four corners. I even thought about using a Cadillac CTSV fuel module, but was unable to find a way to pulse width modulate the set-up to use with my low pressure carbureted motor.
I finally came upon a 2 speed pump from Fuelabs and a pair of Holley Hydramats. I wanted to use a larger single Hydramat, but my tank had a baffle right in the middle of it. I was able to fit two Hydramats of 11" x 11" and a 15" x 15" in my tank, which covered the floor of my fuel tank and a few inches of the front and back walls of the tank.
The fuel pump runs at a low speed until triggered to switch to high speed by a simple open closed switch. I will hook that up to my secondary's with a on/off NO2 style switch. Once the secondary's begin to open, the switch will close and trigger the high speed operation of the pump. I run a full bypass regulator with an -10AN feed and return. The pump I chose flows 160 GPH at around 15 psi.
I sourced a nice Filler Plate set with nut-ring and some 3/4" submersible fuel line from Harmon Racing cells, so that I could cut an opening in my tank and make the modifications. The set-up I choose should be able to supply plenty of fuel with no air intrusion at a very low resistance to the pump.
Here are some pictures of the Hydramat install in my tank. I decided to mount the fuel pump outside the tank for easier access/maintenance.
The problem I had was that my fuel pump would create a vortex in the fuel and start sucking air once the tank got below 3/4 full. Its essentially the same effect when you drain your bath tube. This caused the pump to work harder and cavitate. It took me a while to figure out what was going on.
I thought about how to have a street friendly fuel system that would be able to use most of the fuel in the tank without sucking air. Especially during hard launches and cornering. I initially looked at baffled fuel traps like they use in road course cars, and then looked at snowmobile style pick-ups in all four corners. I even thought about using a Cadillac CTSV fuel module, but was unable to find a way to pulse width modulate the set-up to use with my low pressure carbureted motor.
I finally came upon a 2 speed pump from Fuelabs and a pair of Holley Hydramats. I wanted to use a larger single Hydramat, but my tank had a baffle right in the middle of it. I was able to fit two Hydramats of 11" x 11" and a 15" x 15" in my tank, which covered the floor of my fuel tank and a few inches of the front and back walls of the tank.
The fuel pump runs at a low speed until triggered to switch to high speed by a simple open closed switch. I will hook that up to my secondary's with a on/off NO2 style switch. Once the secondary's begin to open, the switch will close and trigger the high speed operation of the pump. I run a full bypass regulator with an -10AN feed and return. The pump I chose flows 160 GPH at around 15 psi.
I sourced a nice Filler Plate set with nut-ring and some 3/4" submersible fuel line from Harmon Racing cells, so that I could cut an opening in my tank and make the modifications. The set-up I choose should be able to supply plenty of fuel with no air intrusion at a very low resistance to the pump.
Here are some pictures of the Hydramat install in my tank. I decided to mount the fuel pump outside the tank for easier access/maintenance.