Can anyone detail how to do this?

Also, at what power level will this be a good idea/required?

FYI, Full-race geoff mentioned this in a nother related thread:

"... the best thing to do is keep it a stock fuse and run a relay with an extra wire to your fuel pump. this is a trick jason hunt taught me and works extremely well. in fact cortney green uses this to get 680 whp out of his walbro 255.
if you run the relay, run a +12v wire all the way to the fuel pump and use the relay just to turn the fuel pump on. this way when the engine is running you actually get 14.4 v and way more fuel."

 

If you have ever ran wire for a stereo it is the same. The difference being that you install a 30 amp relay inbetween the wire. I suggest using 10 gauge stereo wire for the amp load and a definately add an inline fuse of some sort. Just connect the 10 guage wire to the battery with a fuse shortly behind it. Then add the relay under the hood at a convient location. Run the rest of the aire back to the pump and connect it to the origional power wire to the pump. You could also upgrade the ground wire to a 10 gauge so that you get a stong ground to the puimp also...i sugest it. The next thing would be to look for the ground signal wire from the ecu to stock fuel pump relay. It should be somewhere under the hood. Use that wire to ground the new relay. This is a quick example because I can't give the exact details on every car.

As for the power level to change to a larger wire, i would say anywhere after 300 would be a good idea. i have looked at an airtex fuel pump catalog and it states the fuel pump GPH rates of several cars and the honda pumps are decent pumps. My 91 civic pump is rated at 50GPH, that is roughly 207LPH, i believe. I wouldn't be afraid to run my stock pump with a turbo and wire upgrade. The only thing that scasres me is that my car has 160K on it and i don't know if the pump has ever been replaced.

 

First off, thanks for the great response. They point of the relay is to simply provide power to the pump when the ECU turns on the pump normally, correct?

What about simply upgrading the power wire from the fuse box under the dash to the fuel pump? Then I wouldn't have to worry about the relay...

The other question I have is: Do I still use the stock connector that hooks the original power wire to the fuel pump? Wouldn't that create a bottleneck? If I upgeade the connector, what kind of part can I get to connect the wire to the fuel pump?

I've got a walbro 255 hp pump now, but I'm going for ~500-550whp this season.