Fuel line sizes ???

[arthur39]

Just a question on fuel supply to a Stage one kit, 6lbs boost. I have a billet rail with 3/8 npt threaded inserts, the guy I purchased it from suggested using 8an line or the equivalent 1/2" line from the tank to a 6an or 3/8" return line from the fmu. Is this overkill, or playing it safe? I need to decide on either 3/8 or 1/2 inch barb fittings which will dictate fuel filter size and inlet size from the tank. I have a Walbro 255 pump with 10 x1 internal threads and am not sure of the correct thread to barb fitting size for this insert. Any feedback on this will be helpful as well. (maybe a metric barb)
Later down the road I might do a spacer and 8lbs of boost, that would be the most for my setup. Thank you

 

[arthur39]

found a barb for the walbro pump should work for both 3/8 and 1/2 lines says it is around 7/16 and 1/2 od
Walbro 12 mm hose barb fitting DIYAutoTune.com

 

[15LDE]

Hey mate 3/8 would be heaps for a feed and 5/16 for return if you are using pump fuel.

 

[atticdog]

6 an is plenty and easy to connect the return back to the tank

 

[cdhoroho]

I run -8 feed to my pump then -6 from the pump through the system and return line also

 

[smithabusa]

I agree on 6an, my bike made 460 hp through a 6an feed to the pump from tank.

 

[arthur39]

The gentleman I spoke with said the volume from -8 lines to the pump then to the fuel rails will make a difference with tuning as well, I was just wondering if this was for big numbers or would it be beneficial on a stage one setup as well, I'll probably just do the -8 ( half inch ) to the fuel rails "just because", only question there would be the setup and fittings to come out of the bottom of the "gutted pump" to accomodate the 1/2 inch fuel line, I can find the L fitting 3/8 npt to 1/2 inch barb but what is the fitting that actually bolts through the old pump housing?

 

[arthur39]

Thanks the 3/8" setup will be less harsh on the wallet as well.

 

[smithabusa]

Unless you are going for mondoid hp i would stick with 6an. If i remember correctly I think RCC said he made 600 hp on 6an lines before

 

[arthur39]

alright, I am "sold" on the -6 an from the tank to the rails, this is easier for me as well since I have most of these fittings, just need to buy the new fittings for the billet rail and have them step down to -6 which will be a 3/8" barb for my setup. Thanks everyone

 

[smithabusa]

well from tank to pump, then pump to rails

 

[arthur39]

correct, TY they all came with the kit, I just upgraded to a billet rail seperately and it had me running on a tangent thinking more volume here would be "better"

 

[smithabusa]

gotcha

 

[runrunsteven99busa]

2 adaptors in the oem fuel rail or a billet rail , oem billet oem billet hmmmm 6 an ..well thats what i came to find out and yes 8 an in to the pump stands for reason makes scene , love the information guys