I have a Walbro 420 in the tank now and I want to wire in another pump (Walbro 340). I see that the main connector is outside of the tank but inside the sending unit is two wires (hot and ground) that go to the fuel pump in the plastic can. Can I tap into these wires or will this overload the stock fuel relay or lower the voltage to each individual pump? I would run a dedicated relay and power source but not sure how to plumb it inside the tank, can I tap into the wire connector that is outside the tank somehow?

By the way, I'm running a TT forged 347 setup on my 99 C5 with 15 lbs of boost and about 750 to the wheels. I'm upgrading the entire fuel system by adding two new 8 AN stainless steel braided lines (one primary, one return), plumbed to a boost referenced fuel pressure regulator and over to upgraded fuel rails and 60 lb injectors. Also, what pressure should I run, 60 psi base and 1 psi more for each psi of boost?

Thanks for your help.

 

walmart amp wiring kit $30, wired to the battery and fused. Two auotmotive relays triggered from the original fuel pump power. That's how I did mine.

 

Ok call me an idiot but are you saying that you have two new relays both with 12 volt source coming from the battery, one ground, one trigger from original harness, and one hot to the pumps after being triggered?

If so, where do the hot leads from the relays going to the pumps get wired in since the pumps are in the enclosed tank?

 

original pump feed goes to the coils to trigger the pumps. New power feed goes through the relay to new wires that you run to the pump. I just drilled new holes in my cover and ran new wires. I don't know how the vettes are setup, but it should be pretty easy. If you don't understand wiring get some help from someone who does.

 

Are you running an eboost 2? Rather than running a Hobbs switch, which is what everyone else seems to do, I just wired the negative auxilary output in the eboost to a single relay to come on at x rpm whenever the car begins to make power. You can select the auxilary output to activate the second fuel pump at a specific RPM or Boost level. Pretty awesome I thought and works like a champ! Was really easy to hook up too.
And make sure you run a seperate 10ga. wire WITH fuse to the second fuel pump. You can PM me if you have any questions.