Fuel pressure regulator-Confused!

winkle · Post by **winkle** » Mon Dec 31, 2007 4:20 pm

Hi all,

Im planning on using a bosch 044 pump with pumps at a higher pressure than the standard EFI pump.

If I had a power boost regulator which replaces the standard hotwire regulator, would I also need to regulate the fuel pressure before it reaches the fuel rail?

Got confused with this (not difficult!)

happy new year to all
Steve

kev_the_mole · Post by **kev_the_mole** » Mon Dec 31, 2007 4:32 pm

If you put a standard 1 port in / 1 port out (excluding the vacuum) regulator before the fuel rail then you can't use a system with a fuel return and you may experience fuel overheating problems. If it goes after the the injectors at the end of the fuel rail then you get extra cooling from the fuel rail and the return to the tank / swirl pot.

Here's my diagram for my 6-pot Healey MS project

Fingers crossed I got this right

kiwicar · Post by **kiwicar** » Mon Dec 31, 2007 6:50 pm

so that is what the the oil pressure sender looks like

I wondered which one it was, the temp sender is the other one

.
Thanks
Mike

kev_the_mole · Post by **kev_the_mole** » Tue Jan 01, 2008 3:20 pm

Mike,

It's a 5psi safety switch that cuts out the pumps if there is a catastrophic oil loss!

Not forgotten the throttle bodies but we're on a 7 week lead time and all homers are forbidden.

Happy V8 new year to all.

Ian

kiwicar · Post by **kiwicar** » Tue Jan 01, 2008 3:31 pm

Hi Ian
yup I see now, body/can is the same as the unit I recon is the oil pressure sender though, and the thread is the same, the other unit is totally different.
The throttle bodies are on hold for me at the moment, I am having severe cash flow issues so am doing things that need to be sorted but do not cost much, hence sorting out the flywheel, it needs to be done but would normally wait to later in engine assembly.
Best regards
Mike

winkle · Post by **winkle** » Tue Jan 01, 2008 4:30 pm

OK cheers,

so it doesnt matter if a higher than standard pressure is going into the fuel rail cos the adjustable power boost valve/regulator will send whats not used back to the tank. Am I understanding that right?

Steve.

stevieturbo · Post by **stevieturbo** » Tue Jan 01, 2008 6:06 pm

winkle wrote:Hi all,

Im planning on using a bosch 044 pump with pumps at a higher pressure than the standard EFI pump.

No it doesnt. It may have the abillity to do so, but the fuel pressure regulator 100% dictates pressure seen at the injectors, and of course pump.

If I had a power boost regulator which replaces the standard hotwire regulator, would I also need to regulate the fuel pressure before it reaches the fuel rail?

Got confused with this (not difficult!)

happy new year to all
Steve

The PBR is the fuel pressure regulator, which replaces the factory one... Ideally you need a fuel pressure gauge on this, and to monitor AFR's once installed, to see if it may need raised, or lowered.

DO NOT RANDOMLY ADJUST such a regulator. Very small turns can have a massive effect on fuel pressure, which could burst any pipes not designed for such pressures. This will be made more risky, by using a pump that has the ability to create high pressures.

winkle · Post by **winkle** » Wed Jan 02, 2008 9:53 am

OK, cheers Stevie.

Plumbed the fuel lines in with aeroquip hose for the standard regulator, bugger! Will need some more hose and fitting cos the PBR is a remote fitting

Eliot · Post by **Eliot** » Wed Jan 02, 2008 10:38 am

You should have a EFI fuel filter after the HP pump and before the injectors.

This is my 044 lineup, the pre filter is a simple mesh filter - which isn't great IMO.

stevieturbo · Post by **stevieturbo** » Wed Jan 02, 2008 1:24 pm

winkle wrote:OK, cheers Stevie.

Plumbed the fuel lines in with aeroquip hose for the standard regulator, bugger! Will need some more hose and fitting cos the PBR is a remote fitting

You should not have both regulators in the system. That nearly sounds like you do ?

winkle · Post by **winkle** » Wed Jan 02, 2008 5:40 pm

Will only have the remote PBR Stevie which has been something ive decided to put on as the project has progressed, (pi55 poor preparation)

Will just extend the return line to wherever I mount the PBR.

BTW, cheers Eliot for the photo. Going by what was originally fitted to the car my EFI filter is before the pump?

Steve

stevieturbo · Post by **stevieturbo** » Wed Jan 02, 2008 6:13 pm

If fitting a filter before an EFI pump, it needs to be a BIG FREE FLOWING NON RESTRICTIVE filter....

A restriction before the pump, will cause cavitation, and will lead to premature pump failure, as well as potential fuel supply issues.

stevieturbo · Post by **stevieturbo** » Wed Jan 02, 2008 6:26 pm

Eliot wrote:You should have a EFI fuel filter after the HP pump and before the injectors.

This is my 044 lineup, the pre filter is a simple mesh filter - which isn't great IMO.

In that setup, I'd have put that big filter pre-pump.

I only run a single 100Mic Aeromotive stainless filter pre-both pumps. So far its working fine.

Eliot · Post by **Eliot** » Wed Jan 02, 2008 11:15 pm

I thought you should always put a filter (<25 microns) post pump.
What if the bearings or something else lunched itself insde in the pump?- all your injectors would get clobbered.

That big filter in the picture is a post pump filter, with m12 fittings - which isn't any good as a prepump filter as it would restrict the flow. (its actually of a merc) - part numbers here:
http://www.mez.co.uk/ms13.html

stevieturbo · Post by **stevieturbo** » Wed Jan 02, 2008 11:33 pm

Well....I guess the pump could fail. Although TBH, I dont think Ive ever had a Bosch style pump fall apart that badly. Usually they just stop working.

Ideally I guess you would have a filter after the pump. Space is tight.....and I just didnt bother lol.

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Fuel pressure regulator-Confused!

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