LS4 Front-Drives 2005-2009 - Upgraded fuel pump?

Anyone know what we can use for an upgraded fuel pump? I'm wondering what the high power 3800 v6 w body guys use and if it will work in our tank.

I'm not sure, but it shouldn't be too difficult to wire up an aeromotive or some other aftermarket pump.

A Walbro 255 lph in-tank pump works very well. I use two of these on a stock fuel hangar in my GN which still uses its stock fuel lines; one runs all the time on one 10 AWG +12V feed, the other is staged to kick on at 20 psi using an adjustable pressure switch which triggers another +12V 10 AWG feed back to the tank. These are commonly called "double pumpers" in the Turbo Buick world and they are very effective well into the 9's. I got mine new for about $600 if I recall; it was a bit of a challenge shoving two pumps through the one hole in the top of the tank which I took out of the car. Given where you are at I would think one pump (about $145 for the kit from various Turbo Buick vendors) would suffice. Here is a link to one of the vendors:

http://www.cottonsperformance.com/products.asp?cat=60

...and scroll down about 2/3 of the way down the page. You'll note that is says, "Hot wire kit recommended". If you need help on how to make your own hot wire kit, PM me.

When I raced my '99 supercharged Regal, I hotwired the stock fuel pump and bypassed the silly fuel pump ballast resistor circuitry; the idea of the resistor was to slow the pump down to reduce noise at cruising speed. I did away with all that and used the factory fuel pump wiring to trigger a relay which fed +12V via a 10AWG feed I ran to the back of the car through the passenger compartment, and into the trunk where the fuel pump access was located. Typically the gray wire in the fuel pump harness is your feed; black is ground, and purple is the fuel sender.

Well I ventured away from LS4 tech and found this.
http://www.ls1tech.com/forums/fueling-injection/856954-diy-twin-pumps-quick-cheap.html
I’m thinking I could use the stock pump and add a Walbro 255 on a boost referenced switch. However we have a return less fuel system and I don’t know if we have room in the tank for two pumps. Any body had their pump out or know if this will work?

Brian396,
The pictures in the link you posted is very much what my setup looked like with the same pumps. The only change I would make in the F-body thread is that he is using the small gauge factory wiring to run one pump and too small a gauge +12V feed wire on the second. These pumps take a lot of juice and the larger the gauge wire you use, the more voltage that gets to the back. You need both pressure and volume, particularly on a forced-induction application such as the OP's. I used two 20A fused feeds off the back of the alternator (one for each pump) to two relays (labeled "primary" and "secondary"), then from there two 10 AWG feeds ran to the back of the car; the only wire I used in the factory harness was for the fuel sender. I then located the +12V for the factory fuel pump in the engine compartment and used that to trigger the "primary" relay; doing so retains the 2-second fuel pump prime feature when you first turn the ignition key.

Good info, thanks! I'm also looking at the boost-a-pump options that I've seen out there.

http://www.mphparts.com/prod/107-2350.html

I've heard of these; we tried stuff like this in the Buick world back in the mid 90's and the end result is that it didn't catch on. I'm not sure how much boost you're running to attain 117 MPH as listed in your sig, but IMO $140 for a pump + another $20 for the parts due to a hotwire job is a lot more cost effective and reliable than a $300 gee-whiz widget that proportionally varies voltage depending upon boost.

On my procharger 72 monte I tried an MSD boost a pump. Tested the fuel flow(flowed fuel into a gallon jug for time)before and after installing the boost a pump. It did really increase the volts to the pump but there was only a small improvement in flow. Not worth the money.
On my buick I also have a double pumper system. They work great.


Thank you,
Barry