Which fuel pump with Webers?

[route11]

I'm re-plumbing the fuel system in my '73T. Running Webers with a pressure control unit but which pump to use? Don't want to run a return to tank.

Where is best mounting location?

[cosley]

I've had good results with the Mallory Comp 4070. Comes set from the factory at 5-6 lbs, but you can adjust it down to 3. I mounted mine near the stock pump location. Should be mounted vertically, or as close as you can. I've had 2-Carter pumps fail.

[andyjboy]

I've used a Facet pump (in the same location) & a Malpassi pressure regulator:

[merbesfield]

Can anyone elaborate on the proper fuel pump for Webers? I have seen posts stating that the new Facet pumps are junk. I have no idea and no knowledge. Car is a 66 w Webers. Thanks.

[fromage]

go to NAPA or any quality parts store, I haven't bought a fuel pump in a while, but $50 or less should get you a pump with a warranty, Webbers use low pressure pumps, if you like you can add a pressure regulator to fine tune the fuel flow... the OEM pumps are not worth the price unless you are trying to have a 100 pt car...

[Merv]

This is one of the items I was looking at as well. My 68 has the Webers and came to me with a Facet Solid State pump (see for example: http://compare.ebay.com.au/like/1405...PriceItemTypes ). I have been thinking about replacing it, but it works just fine! I increased the rubber insulation as it is not quiet on idle. My last car had a Mallory pump and regulator. Doesn't seem needed on the Porsche 911 SWB.

[edmayo]

I've had good luck using a low pressure Facet pump with the Bendix decal added for that period look, and I use 10 X 1.00 MM banjos for a more correct appearance. Of course this was correct for the SWB cars but the pump will certainly work for any Weber application. For a LWB application since the pump wasn't originally mounted in the engine bay I'd go with the original location down by the torsion bar tube.

[Merv]

Nice Ed. If I change, that is the one I was looking at. What PSI does it put out?

[chris_seven]

The subject of pumps keeps coming back around and really there are two options that make reasonable sense.

Very early cars with Solex carbs used the Bendix pump (Silver Top?) and this pump can produce a pressure of up to 6.5psi.

The early 911S then swapped this for a Hardi pump which had a simliar delivery capability but max pressure was around 3 psi.

The Hardi pump is still available and is reasonably cost effective, the downside being that they are even nosier then the Bendix/Facet. This pump was also mounted in the engine compartment.

For some reason Facet pumps have developed a repuatation for unreliability over the years but I am not sure that this is deserved.

One of the issues is that it became common practice to mount these pumps horizontally, even Factory prepared Mk1 Escort Rallly cars show this in their preparation manual, and this doen't help them at all as they should be mounted vertically. If you mount them horizontally they will have a tendancy to fail.

Apart from the very low quality replicas the current Facet seems well made and quite reliable.

Eliminating the need to install a pressure regulator also seems a good idea as these devices do cause fuel line restrictons which means operating pressures will increase.

The flow specification quoted for Bendix/Hardi pumps assume 'zero pressure' that is to say the fuel would be pumped into an open tank down a line with little of no flow restriction.

As the 'junk' in the fuel line increases, in terms of number of T pieces, valves and regulators so the pressure needed to allow flow increases.

As line pressure increases flow from the pump reduces and at the maximum stated pressure- say 6.5psi - flow is zero and the engine will cut out.

It is also quite common for engines to develop misfires at sustained high rpm when fuel lines are restrictive and this is almost always due to lack of pump output.

It is important to note that flow is not the enemy of good fuel metering it is the impact of fuel line pressure on needle valves and float height that is the issue.

If you can live with the noise the Hardi pumps are good as the max pressure they generate eliminates the need for a pressure control valve.



If you prefer the appearance of the Facet with a Retro 'Bendix' Sticker then it is possible to internally regulate the pump to a maximum of 2.5-3psi delivery pressure.

We use a replacment pressure control spring which is easy to install and works quite well.

[chris_seven]

The MFI pump fitted to the front of the car has its own By-Pass Regulator designed to protect the filter console in the engine bay.

I believe that this pump has a nominal delivery pressure of 1 bar with the By-Pass pressure set at 2 bar.

If your carbs saw 2 bar then the floats would probably be crushed and even at 1 bar you would be in trouble.

I think PMO make a regulator that con control a K-Jetronic Pump and regulate this pump down to the correct pressure for carbs but I am not sure if an MFI Pump would have enough delivery out put at 3psi but would like to know the answer to this point.