MstgKillr

iTrader: (4)

When should I turn the second fuel pump on with the hobbs switch. Right now I have it set to come on at 0-1 psi., since it takes quite a bit to get to 0-1 psi.

2002 Trans Am WS.6 M6
ATI Procharger D-1SC 8# (3.6 pulley)
Racetronix Walbro twin intank fuel pumps.

2001WS6Vert

I'd say it has to be on by 5lbs. I was thinking 2lbs. would be safe. Your setting sounds fine. I still need to check mine to see exactly when it comes on.

MIGHTYMOUSE

iTrader: (59)

you figure that just one of these pumps can handle 500rwhp easy.. so 5psi is plenty ahead of time for me but i plan to move it all over the place so it affects my part throttle tuning as little as possible... mine cuts on via the turbosmart boost controller.. little red led lights up telling me its on and all that

*lol sorry about the brag, its just pretty neat i think*

MstgKillr

iTrader: (4)

I had my car dyno tuned with LS1 edit and only made 385 RWHP and 425 RWTQ. The shop that did the tune only used one pump and forgot to set the hobbs switch to turn on the second pump with boost. It looked like I started to run out of fuel aroun 4700 RPM. I will be back at the shop and running both pumps and see if they can do any better. I am thinking that since the pumps are T together that I was not seeing the full potential of the one pump. Maybe some of the fuel is bypasing through the other pump. After I got the car home from the shop and tried a few runs my fuel pressure dropped into the 40's while only running one pump. I then set the hobbs switch to turn the other pump on at 0-1 psi and my fuel pressure only drops to 54 psi under 8# of boost. Thanks again for all of your replies.

StalkerLS1

How come you guys just don't run it all the time? I have an inline pump for use with my Vortech and would probably feel more comfortable having it on all the time than to here it clicking on and off constantly.

Just curious...

MstgKillr

iTrader: (4)

I don't know for a fact but I think the twin Walbro's are two much for the stock regulator to run all of the time.

MIGHTYMOUSE

iTrader: (59)

overcycling gas up to the engine and back can get the whole tank of gas very hot in just a few minutes.. not only is this not good for hp, but dangerous. it also puts extra strain on the pumps. you have to run an inline whenever you run your intank all the time because one will impede the other otherwise.

<small>[ April 08, 2003, 08:37 AM: Message edited by: MIGHTYMOUSE ]</small>

Black LS1 T/A

Turn it on as quickly as you can.
I'm almost certain you need the extra fuel right away as you enter boost. This will also keep your fuel more consistent for tuning. My2Cents.