Returnless fuel rails???

[Dustmaker65]

So can someone tell me what the main difference is in the return and returnless setups? And not that one returns the left over fuel and one does not...

There has to be some hang ups on the returnless systems??? What are they?

Thanks!
Jimmy

[Heavymetl]

Returnless works great and is easy to install. No hangups I can think of, as any excess fuel is simply sent back to the tank from the pressure regulator. Many of the factory LS setups are returnless.

[mongocanfly]

one returns leftover fuel and one......oh wait that's not what you wanted....haha...
the only differences I can think of is they're saving money by moving the regulator to the tank from the engine and not having to run another fuel line..both styles work the same as far as I know...my lq9 was a return rail system and I just capped off the return rail with a pushlok and -an fitting...I'm running the vett filter/reg at the tank..

[BR3W CITY]

A return system is easier to swap an aftermarket rail and FPR into if your going into certain boosted setups, alt fuels, or supplemental fuel systems. Just because everything is already in the right place.

[davepl]

I like to run my feed to a Y, which then splits to each rail, and then the rails connect to the regulator and bleed off excess back to the tank. I think that's the ideal setup. I think the regulator should be after the rails and ideally balanced side to side.

[68c10airstream]

Originally Posted by Dustmaker65

So can someone tell me what the main difference is in the return and returnless setups? And not that one returns the left over fuel and one does not...

There has to be some hang ups on the returnless systems??? What are they?

Thanks!
Jimmy

The oems went to returnless fuel systems to reduce the tank vapor load the carbon canister has to deal with. ON the return system in use, engine heat warms the returning fuel and starts warming up the gas tank and the fuel. A lot more vapors to deal with when warm.

Oems also found that at times the pump would be dead headed on the returnless system during decel enleanment (injectors shut off during decel) so they turn off the fuel pump and incorporated pulse width modulated control for the fuel pump. The corvette fuel filter that is used a lot is a blend of return/returnless systems. One line coming from the pump to an outside frame rail mounted corvette filter which incorporates a return line back to the tank, and a regulated outlet to the fuel rail at the engine. This setup does not warm up the returning fuel.

[Dustmaker65]

Thanks guys for the info!

What I really wanted to accomplish was not adding another port to the fuel tank. But if I understand it correctly, I will need another port with either setup.

[mongocanfly]

if you run a external pump or keep the return style rail then yes ...you'll need the extra port...my 81 alraedy had a return line from the ole 350 fuel pump so I used that..

[solidaxel]

Which truck are you going to use,year?