I have an 08 Flex fuel truck. The stock system kept up with a 5.3 (and 12#s of boosts and a 150 dry shot). I changed to a 6.2 and a V7 YSI. I soon ran out of injector and fuel pump. I knew I had to go with two pumps or a Walbro 450.

I didn't want to deal with FPCM problems, or fuel starvation from hacking up the stock fuel pump module, so this is what I did.

I kept the stock system intact and added an Aeromotive 340 LPH fuel pump system. I also added a fuel pressure regulator and return line (I return through the Aeromotive sump). The stock pump feeds the rear of the drivers side fuel rail. My fuel pressure regulator sits on the front of the passenger side fuel rail and the cross over is in the front. I set the return pressure a couple of pounds above the pressure that the stock system runs so that fuel is not returned until the second pump kicks on. I ran a new fuel line from the new pump to the rear of the passenger side rail. I installed a check valve on the new line (near the fuel rail). The stock system runs normal. The second pump turns on with boost and the extra fuel is returned back to to the tank.

The system works nicely. Under boost I am feeding each rail with its own pump and line(stock FF 360 LPH and Aeromotive is 340 LPH). I have been running this way for a couple months now have plenty of fuel.

Install notes:

I had to extend the sump to reach the bottom of the tank (I made my own spacer and didn't spring for the Aeromotive extension.

Since the bed was off I siphoned out the gas and filled the tank with water to drill on it. I siphoned and shop vac'd out the water. I was able to dry the tank out with a rag. Now I have a shiny and clean fuel tank.

There wasn't a great or flat place to mount the kit, but the gasket was thick enough to make it seal. Watch for clearance with your stock fuel level float. My fuel pressure module was aftermarket, but I bet mine sits near where the stock float rides.

Amazon had the best price (by along shot) on the fuel pressure system.

I turned up the prime time on my stock pump to 4 seconds. 2 seconds was not getting enough fuel to the new rails.

Also I have had to kick the pump on earlier than I though I would have to. At first I kicked it on at 7 #s of boosts, but I the pressure would drop more that I was comfortable with. It is a long run through a dry line when the second pump kicks on.


Hope this helps someone.

 

Nice!
You mind taking pics of both sides of the intake where the regulators and fuel lines connect to the fuel rails?