Jump to content
Ultimate Subaru Message Board
moshem74

add mor fuel pressure to the fuel lines...to the carb.

Recommended Posts

hi.

i changed the fuel pump to a stronger one, now the pressuer before the carb is 3psi all the times....if i press the gas or not...it still 3psi all the time.

now, i want to add to the pressure, i want the pressure to be 5psi insted of 3psi.

how can i do it without taking the new one out and change it with a stronger pump?

can i add another inline fuel pump before the carb, on the line than goes into the carb?

can i put 2 fuel pumps on the same line?

thank you all.

moshe.

Share this post


Link to post
Share on other sites

well im not sure exactly what your asking, but i think what your dealing with is a Fuel Pressure Regulator, you can pump all you want and it will still only allow 3 psi in. so get an adjustable, or larger F.P.R.

Share this post


Link to post
Share on other sites
well im not sure exactly what your asking, but i think what your dealing with is a Fuel Pressure Regulator, you can pump all you want and it will still only allow 3 psi in. so get an adjustable, or larger F.P.R.

hi

how can i set the pressure from 3 to 5psi?

Share this post


Link to post
Share on other sites

you need to put some restriction on the return line. like a fuel pressure regulator thats adjustable. from say 1lb to 9lbs, then you dial in what you want.

Share this post


Link to post
Share on other sites
you need to put some restriction on the return line. like a fuel pressure regulator thats adjustable. from say 1lb to 9lbs, then you dial in what you want.
hi

if i'll put a fuel filter ,i'll cut the return line and add a fuel filter, normal simple one, is it will make some restriction on the return line ? it will rise my pressure?

 

moshe.

Share this post


Link to post
Share on other sites

It is unlikely that putting a filter in the return line will create enough restriction. You should be able to find a pressure regulator that only allows fuel to flow through the return line once it has reached a certain pressure.

Share this post


Link to post
Share on other sites

There's a pressure regulator in the fuel delivery line, just after the fuel pump. It's a little thing that looks like a hat, about 2 cm in diameter.

 

You need to replace this regulator with one that can be adjusted. If your fuel pump is itself adjustable (I thought you were going to buy one that could be adjusted), just remove that regulator and use your pump's adjustment.

Share this post


Link to post
Share on other sites
There's a pressure regulator in the fuel delivery line, just after the fuel pump. It's a little thing that looks like a hat, about 2 cm in diameter.

 

You need to replace this regulator with one that can be adjusted. If your fuel pump is itself adjustable (I thought you were going to buy one that could be adjusted), just remove that regulator and use your pump's adjustment.

hi.

this part that you are talking about,a little thing that looks like a hat, about 2 cm in diameter. i took it out already , the fuel line it's without it right now.

 

so.....is there something i can add to the in line or return line, that will rise a little the fuel pressure?

thank you.

moshe.

Share this post


Link to post
Share on other sites
hi.

this part that you are talking about,a little thing that looks like a hat, about 2 cm in diameter. i took it out already , the fuel line it's without it right now.

 

so.....is there something i can add to the in line or return line, that will rise a little the fuel pressure?

thank you.

moshe.

http://www.performancecenter.com/products/?productID=598561

 

Standard Finish Performance Carburetor Fuel Pressure Regulator

spacer.gif

hol_logo_70.gif

hol_12-501_50.jpg spacer.gifspacer.gifRetail Price:

Your Low Price:

Order now. Usually ships within 1 to 2 weeks.

(Click here to find out more)

Note: Regulates Pressure From 4 1/2 - 9 PSI

spacer.gif

blue.info.header.gif

The needle and seat assemblies that are installed in Holley performance carbureotrs can satisfactorily control fuel pressure up to about 8 PSI. If the fuel pump is putting out more than 8 PSI, a regulator should be used to keep the fuel pressure within safe limits and to avoid the possibility of flooding.

  • 3/8in NPT ports
  • .220in (7/32in) restriction
  • High Pressure (4-1/2 - 9 PSI)
  • Includes mounting bracket
  • 1 Year Limited Warranty

spacer.gifInstallation: For vehicles without fuel return line to the tank: Install the regulator close to the carburetor. Fuel lines from the regulator to the carburetor should be #6 (3/8in).

 

Tech Notes: This regulator is designed to work with a single carburetor installation. If two carburetors are used than two regulators will be required, one for each carburetor. Also, two of these regulators must be used when running a VOLUMAX fuel pump- one for each fuel bowl. blue.cust.review.header.gifBe the first person to review this product!

if i'll add this part, will it rise the fuel pressure from 3psi that i have now - to 5 psi ?

Share this post


Link to post
Share on other sites

It sounds as if your fuel pump isn't producing enough output pressure. Check the input voltage at the pump.

 

Pressure regulators cannot increase fuel pressure -- that's a function of the fuel pump. Pressure regulators can only reduce pressure.

Share this post


Link to post
Share on other sites
It sounds as if your fuel pump isn't producing enough output pressure. Check the input voltage at the pump.

 

Pressure regulators cannot increase fuel pressure -- that's a function of the fuel pump. Pressure regulators can only reduce pressure.

For sure. Need more fuel pressure? Then you need bigger fuel pump.

 

Why can't you run the Subaru fuel pump that is supposed to be on there? Did you upgrade to a Weber or something? Can't find a Subaru replacement pump?

Share this post


Link to post
Share on other sites

is there a reason you want more fuel pressure? is the car not running right?

 

i have a carbed car that puts out 2-3 psi all the time, it has always run fine...

 

just curious, i thought 3 psi was an adequate pressure for a carbed car.

Share this post


Link to post
Share on other sites
is there a reason you want more fuel pressure? is the car not running right?

 

i have a carbed car that puts out 2-3 psi all the time, it has always run fine...

 

just curious, i thought 3 psi was an adequate pressure for a carbed car.

The factory spec for hitachi carbs is around 3 psi.

 

What kind of carburetor is on this vehicle?

Share this post


Link to post
Share on other sites

hi

 

the car is runing just fine, the carb it's an hitachi carb (i think i put it from legasi....bigger then the normal)that i change it's DIZA's to a bigger one's, the fuel pump i replace because the original of the car is very slow pump that can't hold pressure, after i put a new electric weber pump, the car drove a lot better....i mean a-l-o-t.

now , lately, i add a fuel pressure claster before the carb, and the fuel pressure showing me all the time 3psi, even on idle or even when i press the gas ....3psi, ont moving up or down.

now, i have an open muffler from the engine to the back all the way, i change to msd ignition,plugs wires, disterbutor,coil,amplifire for stronger spark, also an open air filter and more.....

now, i want to work with this carb at 5psi, what i need to do?

do i have to change the fuel pump ,or there is another way....to add something or to change something?

thank you.

moshe.

Share this post


Link to post
Share on other sites

i see you have made some modifications to your car for more performance- thats great.

 

 

i guess all i am saying is, going from 3 psi to 5psi, is not going to make any difference, the carb is designed to work at 3 psi.

 

i do not think you will get any more performance by increasing fuel pressure.

 

if the car is running good- i just have to ask- why do you need to increase the fuel pressure?

 

as an old saying goes... if it is not broke, dont fix it.

 

not slamming you at all- im just wondering why you want to increase the pressure?

Share this post


Link to post
Share on other sites
you need to put some restriction on the return line. like a fuel pressure regulator thats adjustable. from say 1lb to 9lbs, then you dial in what you want.

like an adjustable regulator! on the return line

 

that little hat thing on the pump is a vibration/pulse damper, not a regulator.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×