Can someone explain the LS1 vs. LT1 fuel,system to me?

I understand that with the LT1's we have your standard feed line, EVAP line, and a return-side regulator. With the LS1 my undertanding is that there's a send line and an EVAP line, and that the system is "returnless". But on some posts I'm seeing a return line mentioned, located somewhere back by the tank.

Can anyone explain this? I don't really have a good visual image of how this fits together.

Thanks!

Return line back by the pump bleeds off the extra unused fuel the same as the TPI or LT1 system. The fuel just doesn't have to go to the engine compartment and back.

Isn't the carbon canister back by (on) the tank too? Is there a vacuum line going back to it to purge it?

So you're saying that... hypothetically... one could run a return line from an LT1 fuel rail all the way back to this bung on the LS1 tank..?

:)

Isn't the carbon canister back by (on) the tank too? Is there a vacuum line going back to it to purge it?

I believe so.

So you're saying that... hypothetically... one could run a return line from an LT1 fuel rail all the way back to this bung on the LS1 tank..?

:)

I would think so as long as you kept the evep. system working.

I think you'd also want to remove the LS1 tanks internal pressure regulation in a situation like that. You could also keep it as it and remove the return line and regulator from your LT1...but now you'd be running at 58 PSI instead of 43.5...so you'd need to mess with programming in the PCM to take care of that (and make sure you use injectors that can function reliably at 58 PSI).