Adjustable fuel pressure regulator

[azmidget91]

So some of you may know about my 32 ford I'm building. Anyways, the engine I got has a holley adjustable fuel pressure regulator. Originally I thought, great one thing I don't need to buy. But then I realized it is not vacuum controlled. So I am assuming the pressure stays constant all the time, is that correct? After doing a lot of searching yesterday I couldn't find much info on it and to me it just seems like a bad idea. Anyways I tried registering to a SVO forum but you have to be let in and so I said and came back here.

Side note, according to my findings people say to run 45psi at idle then add a psi for every psi of boost. I take this as a vacuum controlled regulator would start at 45 at idle and then adjust it automatically when under boost up to 65, and not set it to 65psi at idle if you plan to run 20 psi of boost. Which brings me to another point the holley is only good to 65psi and I plan on running about 20 psi.

So should I toss that holley in the garbage?

http://www.summitracing.com/parts/HLY-512-500-1/

 

[drperry]

Is there an adjustment screw somewhere?

It's probably a constant pressure regulator.

And if you plan on running 20 PSI at idle, you can't really use that regulator anyway... Ditch it for one that suits your pressure range

 

[Texas Jim]

The specs show it has a Boost/Vacuum reference port.
I do not know if that will automatically increase your pressure when you put it under boost load or not.

 

[Texas Jim]

Is there an adjustment screw somewhere?

It's probably a constant pressure regulator.

And if you plan on running 20 PSI at idle, you can't really use that regulator anyway... Ditch it for one that suits your pressure range

He needs 45PSI at idle...

 

[PenguinLTZ]

The specs show it has a Boost/Vacuum reference port.
I do not know if that will automatically increase your pressure when you put it under boost load or not.

They do?

I missed that. But it does say this on the Holley site:
"Holley's trick adjustable pressure regulator will give you 35-65psi to accommodate modifications from mild to wild. A special wave spring maintains constant pressure. Bolts on easily in stock location."

 

[drperry]

Is there an adjustment screw somewhere?

It's probably a constant pressure regulator.

And if you plan on running 20 PSI at idle, you can't really use that regulator anyway... Ditch it for one that suits your pressure range

He needs 45PSI at idle...

I read that part wrong

Either way he needs a different regulator, this one. According to both Summit and the Holley website, it's a constant pressure regulator, adjusted by the screw on the back.

The specs show it has a Boost/Vacuum reference port.
I do not know if that will automatically increase your pressure when you put it under boost load or not.

They do?

I missed that. But it does say this on the Holley site:
"Holley's trick adjustable pressure regulator will give you 35-65psi to accommodate modifications from mild to wild. A special wave spring maintains constant pressure. Bolts on easily in stock location."

Turn the screw for more or less oomph.

 

[Texas Jim]

Summit Racing Part Number HLY-512-500-1
UPC 090127431764

Fuel Gasoline
Pressure Range (psi) 35-65
Regulator Style Return
Regulator Location Fuel rail mount
Boost/Vacuum Reference Port ....... Yes

 

[azmidget91]

Ill have to double check next time I'm at the shop but pretty sure it doesn't have a reference port but you guys have confirmed my theory that I need a differnet one

 

[azmidget91]

another question, I have a walbro 255 inline pump, I know with a holley red fuel pump for a carb its best to have the pump closest to the tank as possible. Is that the same for a higher pressure/volume pump like this?

 

[Texas1911]

If you are running carburated then you need to run a low pressure, high volume pump.

If you are running fuel injection then the fuel pressure doesn't really matter, you set the injector duty cycle via the fuel map for whatever specific volume of flow you need. Fuel injection is done best around 35 - 50 PSI of fuel pressure as that's usually what the injectors are designed for as well as the fuel pump.

The Walbro 255 pumps don't like really high fuel pressures ... they tend to die out or not supply the flow you need. The Bosch Motorsports pumps are rated to astronomical fuel pressures and are a MUCH better fuel pump.

As far as an FPR goes ... as long as it regulates the pressure properly at the rails then it's doing it's job.