Got an electric fuel pump on a DG or DF?

Big lumps of metals and spanners. Including servicing and fluids.

Moderators: Moderators, User administrators

weimarbus
Posts: 581
Joined: 19 Jun 2010, 12:53
80-90 Mem No: 10165
Location: coulsdon

Re: Got an electric fuel pump on a DG or DF?

Post by weimarbus »

Be aware that some electric pumps do not provide enough fuel at motorway speeds, especially on hills.
1985 hi-top 2.1MV with DG carb and LPG
1955 trials buggy with 1.9 DG high lift cam and twin dell's

User avatar
937carrera
Posts: 3322
Joined: 05 Apr 2015, 19:29
80-90 Mem No: 16333
Location: N Yorks.

Re: Got an electric fuel pump on a DG or DF?

Post by 937carrera »

Really ?

I looked at this : https://www.merlinmotorsport.co.uk/p/fa ... -fac-60106

26 gallons / hour is 2 litres a minute which should be more than adequate

Or look at it another way.... say 80 mph at 4 mpg is 20 gallons per hour
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

User avatar
itchyfeet
Posts: 12366
Joined: 23 Jul 2007, 17:24
80-90 Mem No: 12733
Location: South Hampshire

Re: Got an electric fuel pump on a DG or DF?

Post by itchyfeet »

Whats wrong with a T25 injection fuel pump?
1988 DG WBX LPG Tin Top
1989 DJ digijet WBX Holdsworth Villa 3 Pop Top
itchylinks

User avatar
bigherb
Posts: 2394
Joined: 27 Mar 2008, 13:50
80-90 Mem No: 5789
Location: West Kent

Re: Got an electric fuel pump on a DG or DF?

Post by bigherb »

itchyfeet wrote:Whats wrong with a T25 injection fuel pump?
Nothing, if you have fuel injection.

As far as Facet Posiflow pumps go I've never had a problem with a 2l with twin carbs and they can drink fuel at 70+ mph
1982 Camper 1970 1500 Beetle Various Skoda's, Ariel Arrow

User avatar
itchyfeet
Posts: 12366
Joined: 23 Jul 2007, 17:24
80-90 Mem No: 12733
Location: South Hampshire

Re: Got an electric fuel pump on a DG or DF?

Post by itchyfeet »

bigherb wrote:
itchyfeet wrote:Whats wrong with a T25 injection fuel pump?
Nothing, if you have fuel injection.

As far as Facet Posiflow pumps go I've never had a problem with a 2l with twin carbs and they can drink fuel at 70+ mph


let me rephrase, whats wrong with a T25 injection pump for a DG or DF or one of those early prototypes?
1988 DG WBX LPG Tin Top
1989 DJ digijet WBX Holdsworth Villa 3 Pop Top
itchylinks

User avatar
bigherb
Posts: 2394
Joined: 27 Mar 2008, 13:50
80-90 Mem No: 5789
Location: West Kent

Re: Got an electric fuel pump on a DG or DF?

Post by bigherb »

itchyfeet wrote:
bigherb wrote:
itchyfeet wrote:Whats wrong with a T25 injection fuel pump?
Nothing, if you have fuel injection.

As far as Facet Posiflow pumps go I've never had a problem with a 2l with twin carbs and they can drink fuel at 70+ mph


let me rephrase, whats wrong with a T25 injection pump for a DG or DF or one of those early prototypes?
It is a constant flow pump at much higher pressure.
1982 Camper 1970 1500 Beetle Various Skoda's, Ariel Arrow

User avatar
937carrera
Posts: 3322
Joined: 05 Apr 2015, 19:29
80-90 Mem No: 16333
Location: N Yorks.

Re: Got an electric fuel pump on a DG or DF?

Post by 937carrera »

itchyfeet wrote:Whats wrong with a T25 injection fuel pump?

It's all about pressure and flow.

A carb engine needs the flow of fuel to allow the engine to develop the power it needs. The pipework is not designed for high pressure, so is more prone to leaks with high pressure.

FI systems require the same flow at a certain pressure to deliver the required fuel correctly. Typically an injection pump will operate at 5 bar with the regulator set at 3. The pump I linked to, based on earlier comments, runs at 0.3 bar.
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

weimarbus
Posts: 581
Joined: 19 Jun 2010, 12:53
80-90 Mem No: 10165
Location: coulsdon

Re: Got an electric fuel pump on a DG or DF?

Post by weimarbus »

937carrera wrote:Really ?

I looked at this : https://www.merlinmotorsport.co.uk/p/fa ... -fac-60106

26 gallons / hour is 2 litres a minute which should be more than adequate

Or look at it another way.... say 80 mph at 4 mpg is 20 gallons per hour
I can see that the figures work, but can only speak from experience with the pump as installed when I changed to LPG. The pump was bought new( not a Chinese copy) and fitted with the relay and petrol supply solenoid in the engine compartment, when switched to petrol more than 3/4 throttle would create fuel starvation on the motorway, having thought that the pump was fitted too far from the tank, I then moved it to the chassis rail by the tank outlet, it made no difference. I then changed to the cube type pump and issue has been resolved. I can only conclude that the posiflow was not able to supply enough fuel, was faulty, or that the cut off solenoid creates a significant restriction. The same symptoms occurred with both a Weber carb and the Pierburg when put back on.

P.S. having rebuilt the Pierburg and put it back on the camper I have noticed that the overall performance is the same but watching the air/ fuel gauge shows that the Weber has a cruder on/off lean/rich delivery where the Pierburg is more subtle . Strangely consumption appears to be the same.
1985 hi-top 2.1MV with DG carb and LPG
1955 trials buggy with 1.9 DG high lift cam and twin dell's

User avatar
itchyfeet
Posts: 12366
Joined: 23 Jul 2007, 17:24
80-90 Mem No: 12733
Location: South Hampshire

Re: Got an electric fuel pump on a DG or DF?

Post by itchyfeet »

937carrera wrote:
itchyfeet wrote:Whats wrong with a T25 injection fuel pump?

It's all about pressure and flow.

A carb engine needs the flow of fuel to allow the engine to develop the power it needs. The pipework is not designed for high pressure, so is more prone to leaks with high pressure.

FI systems require the same flow at a certain pressure to deliver the required fuel correctly. Typically an injection pump will operate at 5 bar with the regulator set at 3. The pump I linked to, based on earlier comments, runs at 0.3 bar.

:ok which just goes to show there is a lot more to it then just bodging in a pump.
1988 DG WBX LPG Tin Top
1989 DJ digijet WBX Holdsworth Villa 3 Pop Top
itchylinks

User avatar
itchyfeet
Posts: 12366
Joined: 23 Jul 2007, 17:24
80-90 Mem No: 12733
Location: South Hampshire

Re: Got an electric fuel pump on a DG or DF?

Post by itchyfeet »

bigherb wrote: It is a constant flow pump at much higher pressure.

:ok
1988 DG WBX LPG Tin Top
1989 DJ digijet WBX Holdsworth Villa 3 Pop Top
itchylinks

User avatar
Mocki
Membership Admin
Posts: 14830
Joined: 29 Sep 2005, 09:27
80-90 Mem No: 428
Location: Mansfield tel/txt 07947137911
Contact:

Re: Got an electric fuel pump on a DG or DF?

Post by Mocki »

the cheap ( and some may say nasty ) square farct pump for about £15 off the bay of fleas can happily deliver enough for my 2.1 of a carb at any speed ....

no need for any regulator and sits happily on the inner sill by the tank ..... ok, you can hear it at idle, but that is a good thing in my book, i know its working and can hear when the carb has fuel when strting from dry
https://www.ebay.co.uk/itm/UNIVERSAL-SO ... SwKtVWzCvd" onclick="window.open(this.href);return false;
Steve
tel / txt 07947137911
Image
just one shade of very fast grey
________________

1989 2.1LpgWBX HiTop Leisuredrive Camper

User avatar
itchyfeet
Posts: 12366
Joined: 23 Jul 2007, 17:24
80-90 Mem No: 12733
Location: South Hampshire

Re: Got an electric fuel pump on a DG or DF?

Post by itchyfeet »

weimarbus wrote: I then changed to the cube type pump and issue has been resolved.

Do you have a link to this please?
1988 DG WBX LPG Tin Top
1989 DJ digijet WBX Holdsworth Villa 3 Pop Top
itchylinks

User avatar
T25Convert
Posts: 352
Joined: 20 Jun 2009, 09:27
80-90 Mem No: 7819
Location: Chester

Re: Got an electric fuel pump on a DG or DF?

Post by T25Convert »

weimarbus wrote:
937carrera wrote:Really ?

I looked at this : https://www.merlinmotorsport.co.uk/p/fa ... -fac-60106

26 gallons / hour is 2 litres a minute which should be more than adequate

Or look at it another way.... say 80 mph at 4 mpg is 20 gallons per hour
I can see that the figures work, but can only speak from experience with the pump as installed when I changed to LPG. The pump was bought new( not a Chinese copy) and fitted with the relay and petrol supply solenoid in the engine compartment, when switched to petrol more than 3/4 throttle would create fuel starvation on the motorway, having thought that the pump was fitted too far from the tank, I then moved it to the chassis rail by the tank outlet, it made no difference. I then changed to the cube type pump and issue has been resolved. I can only conclude that the posiflow was not able to supply enough fuel, was faulty, or that the cut off solenoid creates a significant restriction. The same symptoms occurred with both a Weber carb and the Pierburg when put back on.

P.S. having rebuilt the Pierburg and put it back on the camper I have noticed that the overall performance is the same but watching the air/ fuel gauge shows that the Weber has a cruder on/off lean/rich delivery where the Pierburg is more subtle . Strangely consumption appears to be the same.

You must have been unlucky! I have had posiflow on 1.9 WBX with webber, pierberg and twin 40 HPMX carbs and it fed all of them fine (plus some very thirsty air cooled stuff). They are push pumps rather than pull, so need to sit next to tank outlet. Only issue is that they are very sensitive to small particles so good filter is important.

And back to what started the thread, need to be wired in so they cut off if you crash. Seen some wired direct to the coil which is terrifying as coil and hence pump can remain live when you are upside in a ditch, just pumping petrol out at 26 gallons an hour....
RIP - George - 1.9DG '85 AutoSleeper Trident - rusted away

George Second - 1.9DG '89 Caravelle

weimarbus
Posts: 581
Joined: 19 Jun 2010, 12:53
80-90 Mem No: 10165
Location: coulsdon

Re: Got an electric fuel pump on a DG or DF?

Post by weimarbus »

itchyfeet wrote:
weimarbus wrote: I then changed to the cube type pump and issue has been resolved.

Do you have a link to this please?[/quote

Sorry Itchy, I'm a dinosaur with computers, so don't know how to do link. I bought the genuine 'fast road engine' cube from 'Demon tweeks'. but with a recco from Mocki for the fleabay one it has to be worth a try at £15 . I had a cheaper copy on the buggy feeding the twin Dellortos and it was fine.
1985 hi-top 2.1MV with DG carb and LPG
1955 trials buggy with 1.9 DG high lift cam and twin dell's

User avatar
Whitevanman
Posts: 58
Joined: 18 Oct 2007, 17:39
80-90 Mem No: 12492
Location: Medstead, Hants

Re: Got an electric fuel pump on a DG or DF?

Post by Whitevanman »

Hi, I'm planning on fitting a facet poziflow pump but unclear about the regulator. Assume I need one though as up to 6 PSI at the carb seems high and risking leaks. Any experiences of this setup welcome. Thanks Mark

Post Reply