electric fuel pump pressure?

Road-race engines and ancillaries - general discussion
bernie
Posts: 24
Joined: Sun Jun 25, 2006 12:49 pm
Location: Southampton UK
Contact:

electric fuel pump pressure?

Post by bernie » Mon May 14, 2012 5:09 pm

Fairly simple request but I cannot find the answer in my book collection.

I would like to replace the original electric fuel pump in my 1976 Fiat 124 Spider 1800cc CS1.
Engine, carb and tune are standard spec.
1.What is the standard spec pressure of the pump?
2.Anyone recommend a pump to fit and is a regulator necessary?

Thanks
Book 28
Too many 124

Urbancamo
Posts: 317
Joined: Mon Aug 08, 2011 2:04 pm
Location: Finland
Contact:

Re: electric fuel pump pressure?

Post by Urbancamo » Mon May 14, 2012 7:06 pm

Basically all Weber and Dellorto carbs like to have fuel pressure in 0.2 bar region. Definately not much more.
You want enought flow but no high pressure. Regulator is not necessary if fuel pressure isn't too high.

I personally like German engineered and manufactured Huco pumps, they are quiet and very reliable. But every one might have their own opinion here.

T
GC_25

nabihelosta
Posts: 94
Joined: Tue Dec 14, 2010 5:37 pm
Location: Lebanon

Re: electric fuel pump pressure?

Post by nabihelosta » Mon May 14, 2012 9:17 pm

If it has twin Webers, I'd go with a Facet Silver Top fuel pump, trunk mounted (as it is a pusher).

Monitor your fuel pressure with a gauge. Try to stay between 3 and 4 PSI (0.2-0.3 BAR) pump on, engine off. If it isn't possible for any reason, you can always use a Filter King regulator, or borrow some Alfa Romeo Giulietta regulator (built-in fuel filter).

Thank you.

(P.S: I have seen some cars lately, using japanese made fuel pumps, same interruptor type as the Facet, originary equipping carbed Hondas or Mitsubishis from mid nineties. Is that even an option/alternative?? Thank you).

Nabih
HORSEPOWERunlimited

Guy Croft
Site Admin
Posts: 5032
Joined: Sun Jun 18, 2006 10:31 am
Location: Lincoln, UK
Contact:

Re: electric fuel pump pressure?

Post by Guy Croft » Tue May 15, 2012 12:26 pm

90% of my reason for using Facet is I can get them very easily thru reliable friends Northampton Motorsport*

I only started using Malpassi Filter King units quite recently, no matter that I rebuilt IDF carbs with great care - much more than 4psi line pressure (engine off - measured at the carb) they showed an alarming tendency to flood and fill up the barrel with gasoline.


G

* shameless 'plug' there...

bernie
Posts: 24
Joined: Sun Jun 25, 2006 12:49 pm
Location: Southampton UK
Contact:

Re: electric fuel pump pressure?

Post by bernie » Wed May 16, 2012 6:41 pm

Thanks to all for their response.

I see Facet pumps come in various pressures namely
1.5 to 2.5 psi SS500
2.5 to 3.5 psi SS501
4.0 to 5.5 psi

Care to say which I need?
Book 28
Too many 124

turbofiat
Posts: 67
Joined: Thu Nov 30, 2006 10:09 pm
Location: Kingsport, Tennessee, USA
Contact:

Re: electric fuel pump pressure?

Post by turbofiat » Thu May 17, 2012 4:39 pm

Is there anyway to properly measure the pressure with a diaphram type pump? The only time I've ever managed to measure fuel pressure properly is with a rotary vain type (Bosch L-jet).

With mechanical or electric style with uses a diaphram, the pressure guage flickers like mad and it's hard to get a good reading.

I don't know it this is a due to the guage itself or this would happen with all pumps. I tried a couple of difference fuel pressure guages on my Yugo but they were not all that expensive (<$20), Mr. Gasket was one of those brands.

I originally had a cheap boost guage on my Yugo that would do this at idle (vacuum mode). I replaced it with a VDO and the needle doesn't flicker. So the VDO guage may have some sort of damper in it where cheaper guages do not.
124 Spider, Yugo,131

Brit01
Posts: 825
Joined: Tue Jun 28, 2011 5:54 pm
Location: Uruguay

Re: electric fuel pump pressure?

Post by Brit01 » Thu May 17, 2012 4:48 pm

turbofiat,

If you have fluctuations you can use a small damping advice as I do with a vacuum meter when measuring the carbs. I use a small aquarium air pump tap that I can use to smooth out the fluctuations.

I'm sure this would work with the fuel also. (as long as it doesn't leak). Test it with water first.

bernie
Posts: 24
Joined: Sun Jun 25, 2006 12:49 pm
Location: Southampton UK
Contact:

Re: electric fuel pump pressure?

Post by bernie » Thu May 17, 2012 4:57 pm

I suppose the SS500 is probably suitable?
Book 28
Too many 124

Guy Croft
Site Admin
Posts: 5032
Joined: Sun Jun 18, 2006 10:31 am
Location: Lincoln, UK
Contact:

Re: electric fuel pump pressure?

Post by Guy Croft » Fri May 18, 2012 9:37 am

Yes, that's the one. Here is the link to the UK importer, FSE.

http://www.fuelsystem.co.uk

Among other things there is a very good page on the Facet fuel pumps giving part nos and data. I have the pump page printed off and refer to it frequently.

G

bernie
Posts: 24
Joined: Sun Jun 25, 2006 12:49 pm
Location: Southampton UK
Contact:

Re: electric fuel pump pressure?

Post by bernie » Fri May 18, 2012 10:41 am

Thanks Guy
Book 28
Too many 124

Brit01
Posts: 825
Joined: Tue Jun 28, 2011 5:54 pm
Location: Uruguay

Re: electric fuel pump pressure?

Post by Brit01 » Fri May 18, 2012 1:11 pm

What's the difference between the cube and posi-flow facet pumps?

Chris

Guy Croft
Site Admin
Posts: 5032
Joined: Sun Jun 18, 2006 10:31 am
Location: Lincoln, UK
Contact:

Re: electric fuel pump pressure?

Post by Guy Croft » Fri May 18, 2012 2:26 pm

Dunno really Chris, always just favoured the more expensive cylindrical ones.

From memory I think the little square ones are a bit noisy.

G

Brit01
Posts: 825
Joined: Tue Jun 28, 2011 5:54 pm
Location: Uruguay

Re: electric fuel pump pressure?

Post by Brit01 » Fri May 18, 2012 7:30 pm

Thanks Guy.

And they look nicer! Well no need for a Facet right now in my case. My mechanic has got the new QH pump going so lets see how it behaves after a week of sitting around. The diaphragm was much thicker than the old one (I suspect they changed the old one here in Uruguay one time due to the messed up cross head screws!!). New one is Italian made and sold by a British company, QH. Nice 3mm allen bolts holding down the diaphragm instead of screws.

Chris

Guy Croft
Site Admin
Posts: 5032
Joined: Sun Jun 18, 2006 10:31 am
Location: Lincoln, UK
Contact:

Re: electric fuel pump pressure?

Post by Guy Croft » Sat May 19, 2012 12:26 pm

I have never found QA to be anything but good..

G

bernie
Posts: 24
Joined: Sun Jun 25, 2006 12:49 pm
Location: Southampton UK
Contact:

Re: electric fuel pump pressure?

Post by bernie » Sat May 19, 2012 7:56 pm

Guy Croft wrote:I have never found QA to be anything but good..

G
Freudian slip Guy?
Book 28
Too many 124

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest