setting up a holley fuel pressure reg.

[67worshipper]

guys im trying to set up a holley fuel pressure reg without a gauge(dont ask) now ive read that they regulate from 4 to 9 psi.is this correct? im assuming that if you wind the allen headed screw in its closing the fuel (lowering the pressure) and winding out is raising the pressure? is there a stop to the screw? thanks in advance.

[benssp]

if you use the principle of squeezing the end of a hose pipe, you'll want to wind it out to lower the pressure

[67worshipper]

thanks ben.it makes the hole smaller then.is there a stop setting to it then? thanks again.

[Russell]

wind all the way in and then a couple of turns back is all you need, the gauges are quite poor as the pressure is so low, keep an eye out for fuel being pushed past the carbs, this will mean its still too high

[Jason Foster]

I think the 4 to 9 lb reg. is too big. and no it wont stop it will unscrew all the way out.
 This is the one i used part number 12-500

http://www.holley.com/12-500.asp

[Jim Ratto]

I've never been satisfied with the inconsistent performance of the Holley "fuel T"

I ran one from 1991 until last year.

Enough headaches in 17 years... I switched to this http://cal-look.no/lounge/index.php/topic,7542.0.html

And my Webers and I are much happier. The Holleys always seemed way too sensitive to temperature. Pressure was very inconsistent (no matter whose gauage I used, including Holley's). Could turn the regulator all the way up and carbs still didn't bleed over. In one weekend, I swapped over to Malpassi and at 4.5psi, the carbs flood over, like they should. I changed over the weekend after Christmas, and have not touched it or the carbs since....   

[67worshipper]

I think the 4 to 9 lb reg. is too big. and no it wont stop it will unscrew all the way out.
 This is the one i used part number 12-500

http://www.holley.com/12-500.asp

i realized last night that theres two different pressure regs that holley make.is there any code or markings to differenciate one from the other? many thanks

[BeetleBug]

I think the 4 to 9 lb reg. is too big. and no it wont stop it will unscrew all the way out.
 This is the one i used part number 12-500

http://www.holley.com/12-500.asp

i realized last night that theres two different pressure regs that holley make.is there any code or markings to differenciate one from the other? many thanks

Yes. The high pressure regulator = blue plastic seals for the outlets/inlets. The low pressure regulator = red plastic seals for the outlets/inlets.

[Diederick/DVK]

how do you recognize/differentiate em when they have the fittings installed already

[benssp]

is there a paint mark on the spring? think mine has a red mark

[67worshipper]

thanks guys i may have to strip it off the car and check.

[Jon]

You can't regulate a flow without consumption. There is just no way to do that... when the inlet valves in the carbs close, the pressure in the line after the regulator WILL rise to the max pressure the pump is capable of delivering (unless the intake valve in the carbs open before that time).
The way to regulate it is to make a return line back to the gastank, or buy a fuel pump incapable of making to high pressure.

[alex d]

You can't regulate a flow without consumption. There is just no way to do that... when the inlet valves in the carbs close, the pressure in the line after the regulator WILL rise to the max pressure the pump is capable of delivering (unless the intake valve in the carbs open before that time).
The way to regulate it is to make a return line back to the gastank, or buy a fuel pump incapable of making to high pressure.

what you are saying makes sense, but then how do you explain all those thousands of pressure regulators effectively working? 

[Jon]

what you are saying makes sense, but then how do you explain all those thousands of pressure regulators effectively working? 

This way:

(unless the intake valve in the carbs open before that time).

In other words, when the engine is running, the inlet valves in the carbs let fuel in to the carb thus preventing a high pressure. It comes down to how much your fuel pump delivers compared to how much fuel your engine consumes during idle. With a return line back to tank you can have a really big pump delivering in abundance for quarter mile action and still ALWAYS have the correct pressure.

[67worshipper]

ive just found out from the builder of my car(thanks luke)that ive got a low pressure holley pump(1 to 4 psi).so that saves me a job.will sort out putting a gauge into the line though to keep an eye on the pressure.going to look at my carbs now i think .

[67worshipper]

what you are saying makes sense, but then how do you explain all those thousands of pressure regulators effectively working? 

This way:

(unless the intake valve in the carbs open before that time).

In other words, when the engine is running, the inlet valves in the carbs let fuel in to the carb thus preventing a high pressure. It comes down to how much your fuel pump delivers compared to how much fuel your engine consumes during idle. With a return line back to tank you can have a really big pump delivering in abundance for quarter mile action and still ALWAYS have the correct pressure.

this sounds interesting JHU.ive spoke to work collegue about this regulator and he couldnt see how it was going to stem the flow either the flow of fuel will be far greater than a regulator could take.

[Jon]

This is one of the subjects where real world physics coincide with Aircooled physics 

Most of us use the Holley regulator because it also acts as a splitter for us, but check out what Holley write about the exact same part:
http://www.holley.com/HolleyNews/article.asp?ID=25

[Lids]

my advice is to ditch the holley and buy either a new regulator like a mallory, or buy a fuel pump that has a built in bypass valve..  These have 1 input and 3 outputs, 2 = carbs 1 =return line.  Depending on the model it may even come with a take off port for the pressure gauge.

A return line will make your fuel pump more efficient, and hence your engine run better.

[Steve D.]

Put a gauge on it ONCE!  Stick a guage inline with it and adjust the psi with the motor running.  Start out at 3psi and run the screw down until the motor starts to choke on the fuel- back it out a bit, lock it down, and put the gauge away in the garage.  Don't live day to day on what a gauge says, but don't totally stick your head in the sand.

[lowfastbus]

I just use a simple cheap pump from a german brand, it gives a constant pressure and never had problems with fuel shortage or flooding.
Steve, from steve's VW shop (LGK on here) sold it to me.  Think it gives about 3.5 psi?

Why don't more people use pumps like that?

[Jon]

Why don't more people use pumps like that?

They need higher volume of fuel...  or they just wants something big and beautiful