Rising Rate Adjustable fuel regulator for carby setup.

[Fairlady Z]

 

as per title rising rate fuel pressure regulator for carby setup.

 

Apparently need one of these suckers for my twin stromberg suck through carby turbo setup. kinda explains my carby pissing fuel problem.

 

 

may have had one at some stage and than someone took it of and now full pressure from pump is flooding the carbs.

 

apperently needs 3psi on idle and for 2Psi more than desired boost pressure. there fore needs to be adjustable.

 

i got an efi 0-100PSi but i dont think it will work well under low settings. but ill try anyway. but if someone has the right one ill be interested.

 

 

[1600dave]

Your carb pissing fuel is because you have too much fuel pressure, which overwhelms the needle / seat that should cut off fuel flow when the carb float chamber is full.

 

You need a normal regulator to drop the pressure from the pump, not a rising rate one.

 

What fuel pump are you running ?

[Fairlady Z]

Actually i do need as it has a turbo sitting right behind the carbies. on idle u get 2-3 psi and on boost 12-14si. With stock regulator will lean out on boost ping etc.... we all know what goes after that.

 

 

Your carb pissing fuel is because you have too much fuel pressure, which overwhelms the needle / seat that should cut off fuel flow when the carb float chamber is full.

 

You need a normal regulator to drop the pressure from the pump, not a rising rate one.

[1600dave]

Suck through, yeah ?

 

Turbo's don't pressurise the air at the turbo inlet, only the outlet. You may get 12-14psi in a suck through setup, but only from the turbo outlet through to the inlet valve, not at the carb.

 

You are correct in a blow-through setup where the carby sees the increased pressure from the turbo.

 

A carb isn't like injection, where you get more fuel flow if you put more pressure into it. All more pressure does is cause it to leak.

[Fairlady Z]

yeah you are right

 

its correct for blow through not suck through.

 

oh that makes it easier i got a holley regulator already (somewhere lol)

 

may give that a crack first. going to chuck a fuel pressure gauge see what pressure im getting. though it filled up a 2l bottle quite quick. so got bit of flow. assuming pressure will be right up there.

 

Cheers mate.

 

 

[Fairlady Z]

Fuel pump haven't checked. stock one is still there but disconnected. havent been under the car yet to see it / but sounds like a holley blue chugging away in the back like a diesel.

 

will find out tomorrow

 

[1600dave]

Yep, most carbs can't handle any sort of fuel pressure, only a few psi. The needle and seat allows the float chamber to fill, then cuts off fuel supply (like your toilet cistern). If the fuel pressure is too great, the fuel supply isn't cut off and has to go somewhere (eg leak all over the place).

 

The airflow through the carb just "sucks" the fuel from the float chamber. More boost should = more "suck", therefore more fuel, therefore (hopefully) no leaning out. All the fuel pump has to do is maintain the fuel at the correct level (height, not pressure)in the float chamber.

 

 

[Fairlady Z]

cool cool will let you know how i go tomorrow.

 

replaced/replacing the entire ignition system so that should be 100% add bit of fuel = should run.

 

than I look at how well it starts and runs. i got a bad feeling therese no fuel regulation and has some sort of monster fuel pump.

 

damn work. wan to go home now and check it all out.

 

 

[d3c0y]

Damn pipped to the post by everyone!

[MaygZ]

Don't confuse pressure with volume.  A low pressure/high volume pump with a pressure regulator will get it just right.  Don't forget to ensure there is plenty of scope for fuel return from the carbies back to the tank.  I have in the past seen these lines blocked and the excess fuel has to go somewhere (or the pump simply aerates the fuel).

 

I would also suggest that you spray carbie cleaner through the throats and allow it to soak overnight.  I would be tempted to do it for a couple of days in a row.  This should clean/soften any residue that is sitting in air/fuel bleeds.  Give it chance to breath if it hasn't breathed for a while.