I am building an LS7 for my C5 (2001 Coupe) with significantly more HP than the stock LS1. I have been told that I need to change the fuel system front to back. My question is how the factory system transfers fuel from the right tank to the left tank. I am trying to find out whether or not I need to increase that part of the system or not. I need someone who has done this, any takers?

 

Basically you're doing a high hp upgrade, so I think all they're talking about is making the fuel delivery system (from the left tank) keep up with the demands. I've never heard of anyone messing with the transfer system from the right to left tank.

HTH, and have a good one,
Mike

 

The pressure regulator is in the fuel tank, not on the fuel rail on the engine. This type of fuel system is called
returnless, or demand. This means that excess fuel is diverted before it leaves the tank, instead of passing through the
fuel rail before being diverted. The result is that hot fuel is not constantly returning from the engine compartment, so the
fuel in the tank stays cooler, improving evaporative emissions.

The majority of the pressurized fuel is directed through the filter (L) and on to the fuel feed pipe (M) to the engine, where it
is injected into the cylinders for combustion.

Some of the pressurized fuel is directed through a feed pipe (N) inside the crossover hose, to a siphon jet pump in the
right tank. The jet pump relies on the venturi effect to use pressurized fuel to draw additional fuel from the tank. The
combined fuel then flows from the right tank to the left tank, through a return pipe (P) inside the crossover hose. The jet
pump is able to move enough fuel to ensure that all of the fuel in the right tank is consumed before the level in the left tank
begins to drop.
TIP:
The return tube in the left tank has an anti-siphon hole (S), so the fuel in the left tank does not siphon back to the
right side when the vehicle is shut down.

Some of the pressurized fuel is directed to a venturi pump in the left tank. This pump uses fuel flow to siphon fuel from the
main tank into the reservoir, to keep the turbine pump supplied with fuel at all times. As the left tank fuel level drops, the
venturi pump scavenges all of the remaining fuel into the reservoir, regardless of the vehicle's attitude.

When the engine is shut off and the turbine pump stops, a reverse flow check valve (W) maintains pressure in the system
to ensure rapid pressure buildup during the next startup cycle.

Operation of Fuel Level Gauge
When the fuel system is operating as designed, starting with both tanks full, the left tank will remain full until the right tank
is depleted. Then the left tank will be emptied.

Each fuel tank has its own sensor (Q and R in the illustrations). Modules are shown in
figure 5
(LH module) and
figure 6
(RH module). The PCM supplies a reference of 5 volts to the two sensors. Each sensor operates across a range from full
(2.5 volts) to empty (0.7 volts). The PCM monitors the fuel level sensor voltages and calculates how much fuel is in the
two tanks. The readout of the IP fuel level gauge is a result of this calculation.


You only need to worry about the left tank parts

 

You have been very helpful, thanks for all the detail! But just one question for you, where are the illustrations? On the net somewhere?

.

 

This link will take you there
http://www.corvetteactioncenter.com/...el+Tank+System
It is actually for the FFS fuel system started in 2003.5,
but it works the same. Parts location is the difference

Your profile shows supercharged did you not have to upgrade your fuel sytem?
Here is more fuel stuff
http://www.lingenfelter.com/pdf/c5fu...structions.pdf
http://www.cajundude.com/racetronix.htm
http://www.cajundude.com/bap.htm

 

The first mod I did was the ProCharger D1SC and headers. On the stock engine I was only pushing 8 lbs. I have seen some people go higher on a stock engine but I didn't feel good about it. On the dyno it went from 306 to 438 rwhp. The stock fuel system worked fine. Now that I am building an LS7 (as seen below) from the pump forward has to go.