Fuel pressure regulators

hot66 · Post by **hot66** » Wed Sep 21, 2005 11:33 am

I have a purolator 'dial' style fuel pressure regulator on my 2.0 motor. I have haerd bad things about the reliability of the purolators so I'm thinking of fitting a new regulator.

What fuel pressure regulators are yo using?

Nige · Post by **Nige** » Wed Sep 21, 2005 11:57 am

Well I'm using a rotary fuel pump that provides a constant pressure, so no need for a regulator.

davidppp · Post by **davidppp** » Wed Sep 21, 2005 12:08 pm

Hello, Nige.

Which pump is that please?

I've been looking for one with a reliable low output pressure..so far the only ones I've found are the tick tock spring operated reciprocating type..

Kind regards
David

shambly · Post by **shambly** » Wed Sep 21, 2005 12:34 pm

I'm using a Mallory rotary low pressure pump, which isn't meant to need a regulator..... But I couldn't set it for consistent (2.5psi) low pressure.

So I added a holley type regulator and found this gave a more consistent pressure run to run. (Was attempting to eliminate high fuel pressure as a reason for running rich at the time)

I also performed an experiment with a hand operated mityvac vacuum/pressure pump to generate fuel pressures (using it to pressurize a small fluid chamber containing petrol) to feed one of my carbs.

I found that it took significantly less indicated pressure (on the cars mechanical fuel pressure dial) to overwhelm the needle valves in my 44IDFs with the rotary pump & regulator than it did generating the pressure with a hand operated mityvac pump. This implied that pulsing of fuel pressure was still occuring even with the regulator - the pulses are just too quick for the gauge to register. So you can't necessarily believe what your (damped) gauge is telling you.

Not sure if all this is helpful, but just wanted to share.....

Nige · Post by **Nige** » Wed Sep 21, 2005 12:37 pm

This one down the bottom £49, think its a CB Performance Product

http://www.vwspeedshop.co.uk/pg/fuelsystem.htm

davidppp · Post by **davidppp** » Wed Sep 21, 2005 12:48 pm

Thanks very much, guys..

Shambly that is really very interesting indeed...

As you obviously know, one of the most recalcitrant problems of webers, and even PMO's I'm told, is variations in float chamber level...exacerbated by slosh in corners...

Nige, does the CB pump have a return line to the tank?

Rotary pumps fundamental physics is based on a fixed flow rate...a simple blocking valve regulator, like the Filter King etc is a pretty crude way of attempting to match the variable fuel demand of carbs (or injection if it comes to that) to the fixed output of the pump....

However, injection systems get round this by using a bleed valve allowing excess back to the tank.

I have only seen one regulator, the Holley, which has this provision at low pressures.

Kind regards
David

Nige · Post by **Nige** » Wed Sep 21, 2005 1:23 pm

No fuel return