Fuel Return Line Explain

veilsideboyz

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Oct 28, 2008
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H i ! All master... Can anyone explain to me what's fuel return line use for ?? So far I'm using fuel return line with Sard Regulator almost 1 year..but I am still not too sure what it use for... paiseh :biggrin:
Hope can explain guys....
What If I adjust the regulator to 20psi ?? I am using walbro fuel pump ..
 

rex79gt

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http://www.zerotohundred.com/newforums/car-modification/315112-fuel-return-hose.html
this is the similar thread i opened b4 but without reply til now

1st of all, what car r u driving wif what engine?
fuel return hose is to deliver extra fuel back to yr fuel tank
so yr engine wont run too rich with extra fuel which is not necessary
of which adjustable fuel regulator is to increase yr fuel pressure so when yr ignition sparks, it can burn cleaner for efficiency.
yet i realised some cars don hav fuel return hose nowadays probably juz for cut cost
n which leads to higher FC, n engine running richer that cause power loss
 

SkYwAlKeR

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fuel return line is to increase ur fuel pump lifespan and not to inject too much fuel into the engine... this is particularly important if u have uprated fuel pump... lower engine revs consume less fuel, this increases pressure in ur fuel line.. that is why fuel return line helps reduces pressure in ur fuel line..

fuel pressure regulator works after the fuel rail, on the return path of ur fuel line... fuel regulator blocks/regulates the amount of fuel returning to ur fuel tank, hence increasing/decreasing the fuel pressure inside ur fuel line...

in general (without messing with ecu fuel mapping), increasing fuel pressure will increase ur engine air fuel ratio...
 

changchewsoon

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Oct 10, 2009
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www.viosturbo.com
http://www.zerotohundred.com/newforums/car-modification/315112-fuel-return-hose.html
this is the similar thread i opened b4 but without reply til now

1st of all, what car r u driving wif what engine?
fuel return hose is to deliver extra fuel back to yr fuel tank
so yr engine wont run too rich with extra fuel which is not necessary
of which adjustable fuel regulator is to increase yr fuel pressure so when yr ignition sparks, it can burn cleaner for efficiency.
yet i realised some cars don hav fuel return hose nowadays probably juz for cut cost
n which leads to higher FC, n engine running richer that cause power loss
so you're saying for those car who has returnless fuel setup will run a lot richer and have higher fuel consumption?
 

speed2horizon

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Jun 4, 2006
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so you're saying for those car who has returnless fuel setup will run a lot richer and have higher fuel consumption?
For those engine with no return line, there us a excess fuel pressure bypass valve withn the tank itself. In other words, the fuel pressure wil remain as the optimum pressure within the fuel rail. The excess fuel will be returned within the tank itself.
 
Last edited:

chrissyong

500 RPM
Senior Member
Aug 14, 2007
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H i ! All master... Can anyone explain to me what's fuel return line use for ?? So far I'm using fuel return line with Sard Regulator almost 1 year..but I am still not too sure what it use for... paiseh :biggrin:
Hope can explain guys....
What If I adjust the regulator to 20psi ?? I am using walbro fuel pump ..
bro the fuel regulator kindly set to 30psi 2bar for minimum,20 psi is not good for engine,some more if the fuel pump is good u just install meter only will see 30 psi....
 

hanslin

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FREE BUMP
FOR NEW YEAR:rofl:

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:biggrin:izit true the dual line sys, return line should be bigger than supply so it will slow down the return speed for the fuel cool down time???:biggrin: