weber 40's and fuel pumps

[BLUNT]

i see pics of guys running mechanical pumps with webers and some running electrics. i have a set of 40's ill be running on a 2.3 stroker. should i be looking for an electric pump and if so can anyone recommend a good one? i am a total rookie with carbs so im learning but i thought the side drafts didnt allow room for a mechanical pump but yet ive seen pics of people using them. thanks. i have a regulator that came with the carbs

[TimNC]

This is what I am using since I rebuilt and re-installed my engine this past spring....a Carter 4070 low pressure fuel pump (rated at 4 psi). But, a word of caution...when fuel pressure was checked at carb right after installation, the pressure was actually higher than rated, almost 10 psi. Had to install a fuel pressure regulator and dialed the pressure down. After adjusting and testing a pressure of around 7 psi works best for my 38/38 Weber on pretty much stock engine. Engine starts easily and runs strong, with no problems with fuel delivery at any point during normal and/or "spirited" acceleration. Tim

[Lee]

Hi Blunt.

You will need an electric fuel pump, and pressure regulator set to about 2,5psi. Carter makes external pumps. They work okay and cost in the vicinity of $75. If you run a daily driver and don't want the constant buzz, then you can use an e21 pre-pump assembly and an external regulator. No noise, all hidden in the tank. Easy to plumb. That will allow you the full use of the trunk.

Carter pump.

[HarryPR]

I bought a Mr. Gasket electric pump for the 320i a few weeks ago (I yanked out the pesky FI and installed a 32/36).

It is rated at 7 psi and cost me $44. It has worked great so far.

[steve k.]

run the pressure at about 3.5 PSI. The pump is only there to fill up your bowl, not to push the fuel through the carb. Pressure higher then that will wear the needle valve preternaturally. Always use a regulator and plug a gauge in to it to see the actual pressure. Do not depend on the dial regulators to be accurate.

steve k.

[esty]

This is what I am using since I rebuilt and re-installed my engine this past spring....a Carter 4070 low pressure fuel pump (rated at 4 psi). But, a word of caution...when fuel pressure was checked at carb right after installation, the pressure was actually higher than rated, almost 10 psi. Had to install a fuel pressure regulator and dialed the pressure down. After adjusting and testing a pressure of around 7 psi works best for my 38/38 Weber on pretty much stock engine. Engine starts easily and runs strong, with no problems with fuel delivery at any point during normal and/or "spirited" acceleration. Tim

i 2nd the carter...i'm a mechanical dummy but have used these on my cars for years and never had one fail...on my 2002, i did have to install a fuel pressure regulator to bring the pressure down...i mounted the regulator on the firewall where the fuel line comes out, then down to the carb

[herkjerk]

I also have the carter 4070, which has been installed since '98 with no issues. I useed a cheap regulator from a vw shop which is dialed in at 3.5 and put an inline fuel filter just prior ro the pump. works great with the 45's I have installed

[gone002]

heres mine...

[Mike Self]

plain 'ole mechanical pumps, same as the single carb cars, and they seemed to work OK...why not try the mechanical pump and see if it's adequate to do the job? A lot less hassle than plumbing/wiring an electric pump...

mike

[Mike Self]

plain 'ole mechanical pumps, same as the single carb cars, and they seemed to work OK...why not try the mechanical pump and see if it's adequate to do the job? A lot less hassle than plumbing/wiring an electric pump...

mike

[Guest Anonymous]

You'd have to use the old-style mechanical pump with the bolts around the outside of the diaphragm. The new-style sealed pumps interfere with the choke lever. If you go electric, definitely don't over-do it with pressure/volume capacity. A pump that is too big can overcome the capacity of a regulator and flood your carbs. As stated before, you only need enough fuel volume to keep the bowls full, pressure is not important.

[csmccoy67]

Hey, here's a topic I can chime in on.

I dumped my Carter 4070, because it required the use of a pressure regulator. It made a lot of noise until I tried it without the regulator, but then the pump just overpowered the DCOE float needles and gas poured out of the carbs.

After a little time on the 'net, I came up with a better choice, which has worked as well as the 4070 was supposed to, but didn't... The Carter 60504, sometimes listed as P60504, is smaller, easier to mount, and runs quietly without a pressure regulator!

http://www.partsamerica.com/productdetail.aspx?MfrCode=CTR&MfrPartNumber=P60504&PartType=52&PTSet=A

2 months of use so far, and no complaints.

Chris

[KFunk]

I know this is a point of contention, but according to Summit and other sites, the Carter vane-style rotary pump is actually self-regulated. I couldn't find the link right now, nor do I know the mechanicism by which it does this.

But somehow I bet it adjusts the fuel pressure upon demand. I've been running the Carter for my simple little 32/36 for a couple years now without any external regulator, and we know my car has been abused like hell and driven cross-country. I've had no problems at all with flooding, no smell of gas under the hood, needle valve seems to be fine (haven't visually looked recently), and I get decent gas mileage on the highway for a tired old motor with 250K+ and 4-speed w/3.91.

I've never had the desire to measure the fuel pressure, so I don't know how you guys are doing it. But perhaps your testing it with the Carter running with no load, and the self-regulation hasn't kicked in.

I know there are plenty of others like me that run the Carter without an external regulator, so I don't know why anyone else hasn't spoken up yet. Do a search, its been argued plenty, perhaps they're tired of arguing.

[TobyB]

the race car came with a blue Holley on it-

basically, this thing could act as a bilge pump for the Titantic.

It took several months to find a regulator that can cope with the

absurd amount of pressure and flow this pump develops.

The little Holley it came with is simply overwhelmed.

The only reason I keep it is that it's incredibly fault- tolerant-

with a flow- through regulator, it can suck air, bits of cell foam, small animals

and keep pumping.

I don't recommend this method to anyone. Jenn's car uses the small Carter P60504, and needs no regulator either.

This, I recommend!

fwiw,

Toby

[visionaut]

Hi Steve,

I'm also running the low pressure/high volume Carter 4070 pump with my dual 40 DCOEs. And I don't run a regulator. Fuel delivery works great for me at all levels of throttle/rpms. I also don't have any issues with excess fuel, needles, etc. And I rarely have any noticeable 'buzzing' - only when it's very cold and my isolation mount is stiff, and even then it goes away after a couple of minutes. I also get pretty decent mileage, with all my performance mods considering --18-23mpg on average as my DD.

FWIW, I don't run a 'return line' set-up either - maybe that's a factor with those who found it had too much pressure? (Maybe that affects the 'self-regulating' feature?)

Tom