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#1
advice needed; electric fuel pump w/ 40mm webers
IAMLeon
Posted on: 2011/1/29 12:19
Evening fellas,
Currently rebuilding my a14, fairly worked setup, running twin 40mm webers. I'm after some advice regarding electric fuel pumps and regs, i've already got a small surge tank installed underneath the car, and now just need something to flow a bit more fuel. What's everyone running? thanks!
#2
Re: advice needed; electric fuel pump w/ 40mm webers
clyons8
Posted on: 2011/1/29 12:46
Stock pump works fine for twins. You can get one for about $25.00.
Carter, Holley etc are some of the big name electric ones you could use, regulator would need to keep the pressure below 5psi or so. Most sidedraft carbs like between 3.5 and 5 psi maybe up to 6 so when selecting your regulator make sure it will operate at low or as low as the pressures you want. But a electric setup will cost at least $250 when you consider the fittings, wiring, lines, pump, regulator etc. Volume is also as important as PSI so be mindful of that if you're going for a no-name cheap unit. They might have the right pressure but the volume they provide is often insufficient to feed the pair of thirsty bastards. If you have a surge tank does that mean you will also need a lift pump? is that correct?
#3
Re: advice needed; electric fuel pump w/ 40mm webers
jmac
Posted on: 2011/1/30 0:27
If you run a holley pump, even though they are internally regulated (it's more of a safety thing that pressure maintenance) to 9-12psi depending on model - but even though the holley regulator is a 'deadhead' style (it regulates pressure to the carbs by shutting off supply altogether) - this is 'bad' especially when used for a motor that is going to consume a lot les than the v8s the holley pumps are made for. The pump will run hot, not last as long, and perhaps just as importantly run _loud_/. Get a bypass style regulator in there and then it controls pressure to the carbs by bleeding off excess fuel back tot he tank via a return line (that you'd have to fabricate, and don't use the existing supply line, it's too small and restrictive enough that it won't be able to return the fuel tot he tank quickly enough and the pressure will soar up to the pumps limits,
The surge tank isn't a bad idea at all, but I will mention just for the record that the holley fuel pumps are reasonably happy to 'pull' fuel from the tank, and don't need an in tank lift pump or anything. they should still be mounted as close to the tank as possible so they are still mostly 'pushing' fuel rather than pulling it. But do it right with a bypass regulator and decent diameter supply and return pipes, and the holley pumps will last 2-3 times as long as normal and be a lot quieter. If you ever do rallying, then the bumps will tend to knock the regualtor off it's seat (or onto it) and cause fluctuating fuel pressure. And the float will bounce up and down too and might cause carb metering 'shenigans' (it'd have to eb a fairly rough course though, rougher than most I can think of in Aus.
#4
Re: advice needed; electric fuel pump w/ 40mm webers
1200rallycar
Posted on: 2011/1/30 7:04
one tip - don't get too fancy
stock pump will definitely do the job (we are running it on our rally car) holley is poo - so is carter and neither suit what you need (they are loud, require priming and unreliable) bursons near me had a few pumps for $30 on the counter, would be perfect. the old L28 patrol pump - which they still sell new today as a V8 supercar lift pump (400plus bux) are awesome if your willing to go second hand - $40 just get the typical 4-6psi pump, anything more requires an expensive regulator or it just overcomes the needle and seat no wait - i take it back - just use stock, what body shape is your 1200 and what are you using it for? (helps us understand why you have a surge tank)
#5
Re: advice needed; electric fuel pump w/ 40mm webers
lamb_daiquiri
Posted on: 2011/1/30 8:28
Sorry to go off track, which Bursons? I'm slowly collecting parts to go efi on my a15 and have been looking around for an electric pump to fill my surge tank. $30 is the best price I've heard of.
#6
Re: advice needed; electric fuel pump w/ 40mm webers
IAMLeon
Posted on: 2011/1/30 8:36
I'm hearing lots of conflicting information, weber themselves have recommended a Carter pump. The last owner used to circuit race it so that's where the surge was obviously implemented. My engine builders have had issues with fuel flow running carbs like the on the stock pump. As far as I know I shouldn't require a lift pump as it's running lower pressure.
Im running it in a sedan also.
#7
Re: advice needed; electric fuel pump w/ 40mm webers
woody
Posted on: 2011/1/30 8:42
on my race a15 im running twin 40mm webers with a holley black pump. i agree its massive overkill, noisy, and is a bit of a bugger to mount at times due to the layout of the pump. im also running a walbro adjustable pressure reg at the firewall which runs at 4psi. webers dont like much more pressure than 4-6psi.
on my turbo a12 im just running a standard pump and its holding up just fine so i dont think you will have an issue with a standard pump setup, but i would upgrade the supply lines to 10mm including in the tank like i have in my race coupe just as added insurance
#8
Re: advice needed; electric fuel pump w/ 40mm webers
ddgonzal
Posted on: 2011/1/30 9:33
Quote:
weber themselves have recommended a Carter pump that's because Weber carburetors will work fine with a carter pump (regulated to 4 psi). Weber is not saying whether the carter pump is reliable. But people keep asking them what electric fuel pump to use, so they have recommended one. You don't need an electric pump even for racing. A surge tank can be useful. But remember that carburetors have built-in surge tanks -- the carb float chambers.
#9
Re: advice needed; electric fuel pump w/ 40mm webers
ssskiwi
Posted on: 2011/1/30 10:08
The biggest electric pump I have ever run on a 1200 (actually 1300 odd CC pulling to 9k RPM on twin DHLA) was a solid state Facet.
With a 3/8" fuel system (incl the tank outlet, all barbed fittings, hoses etc.) it kept up no problem, in fact, increasing everything to 3/8" (prev only the line was 3/8") all the way through actually decreased the pump activity! I have heard the Filter King regs are the best for carb use as they do not limit flow when regulating and the adj range is perfect for carbs 1 - 5 psi, they also have a built in fuel filter bowl and optional gauge.
#10
Re: advice needed; electric fuel pump w/ 40mm webers
1200rallycar
Posted on: 2011/1/30 11:02
ill see if they have them still tomoz, gotta get one for supafatto potentially, ill grab two if you wanna grab one off me
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