Fuel inlet info sought

[HandyAndy]

Hi all,

I,m looking at connecting up the installed fuel line to my carb ( standard carb setup) on my CVH,
my question is this.........

Do i NEED to run a return fuel line back to the tank from the fuel vapour seperator or can i ditch the seperator ( its in the engine bay) , or keep it in place & just run a short return line from the seperator & "T" it into the fuel line that feeds the fuel pump (which is attached to the top of then engine)?

your thoughts/suggestions are welcomed.

The reason i,m asking is that i intend to run bike carbs so won,t need a return back to the tank, so i,m being both lazy & forward thinking

cheers
andy

[twinturbo]

I would put the return in, i think the vapour preasure trap is there to prevent the carb being over preasured which may lead to the car running rich.

And anyway. when yo step up from the bike carbs to the throttle body injection on megasquirt your going to need the return

TT

[gus]

Hi Andy,

I had the same discussion with AdrianH. We both threw the vapour serperator in the bin. Mine runs fine without it.

Like you said I have looked at running bike carbs in the future, and by using a bike interrupter fuel pump you don't need the return to the tank.

I wouldn't both with it in my opinion.

Cheers

Gus

[HandyAndy]

Originally Posted by gus

Hi Andy,

I had the same discussion with AdrianH. We both threw the vapour serperator in the bin. Mine runs fine without it.

Like you said I have looked at running bike carbs in the future, and by using a bike interrupter fuel pump you don't need the return to the tank.

I wouldn't both with it in my opinion.

Cheers

Gus

cheers "Gus",

that was my thoughts, but just wanted someones opinion on whether i,m thinking right

so , are you saying to just run the fuel line straight into the fuel pump & ditch the seperator all together?
thanks for your help

Twin Turbo.....

That also was on my mind but then thought that the carb wouldn,t get under pressure as any surplus fuel vapour would still be in the fuel seperator but fed straight back into the fuel line going into the fuel pump, instead of travelling all the way back to the tank, if that makes sense. tho i might be wrong

cheers
andy

[gus]

Andy,

I ran the pipe from the tank through a filter & then onto the pump. From the pump straight onto the carb.

I think this is what most people will say. I think I have seen this come up on LCB builders before, and they all say to bin it.

Cheers

Gus

[HandyAndy]

Originally Posted by gus

Andy,

I ran the pipe from the tank through a filter & then onto the pump. From the pump straight onto the carb.

I think this is what most people will say. I think I have seen this come up on LCB builders before, and they all say to bin it.

Cheers

Gus

cheers Gus,

just what i wanted to hear (read)

thanks for your help.

cheers
andy

[baz-r]

the pierburg 2e3 (sierra cvh carb) shuold be fitted with a return line you dont need the seperator just a t pice with a restristion on the return side (old carb jet screwed in)
if you have no return line you will get one of two problems the float will hold back the pressure and the fuel pump will not follow the cam damaging it
or the float will get pushed down changing your fuel hight in the float chamber

also worth thinking about vapor lock in hot weather

[HandyAndy]

Originally Posted by baz-r

the pierburg 2e3 (sierra cvh carb) shuold be fitted with a return line you dont need the seperator just a t pice with a restristion on the return side (old carb jet screwed in)
if you have no return line you will get one of two problems the float will hold back the pressure and the fuel pump will not follow the cam damaging it
or the float will get pushed down changing your fuel hight in the float chamber

also worth thinking about vapor lock in hot weather

so, a return from the carb fed back into the "fuel in" supply to the fuel pump with a "one way" valve in? would that do the trick Baz-r ?

thanks
andy

[AshG]

got binned mine runs fine without it. put a mini filter up by the carb the nature of them means they never fully fill up so theoretically it will give you a bit of expansion. the pump shouldn't really pump more fuel than the engine can use as they work with the rpm of the engine.

from what i understood the vapour separators were only used to eek that extra bit of fuel economy.

[HandyAndy]

cheers Ash, i like the comment on the fuel economy, i,d heard that before too.

cheers for all your suggestions guys.

cheers
andy