Dual fuel pumps?

[sepulchralx]

Just curious how some owners run dual fuel pumps? In a normal pumping situation each pump (in most applications, boiler feed pump, water pumps, etc) have check valves right at their discharge. Do people run check-type valves on a dual fuel pump setup? And is an extra voltage source needed for a secondary pump, or can you just split off the stock wiring?

Also in the case of the S14, would it be best to modify the pump holding bracket to house two pumps? Or do some people just lay the secondary pump at the bottom of the fuel tank and leave it sit?

JW Thanks!

[Darius]

Why would you need check valves in a parallel setup? The pumps are going to be running simultaneously.

I would run separate wiring to each pump and make it heavier gauge than stock too.

Not sure what most people do, but I can't imagine trying to squeeze two pumps down in there. I had a hard enough time getting the damn supra tt pump in there.

[sepulchralx]

Why would you need check valves in a parallel setup? The pumps are going to be running simultaneously.

I would run separate wiring to each pump and make it heavier gauge than stock too.

Not sure what most people do, but I can't imagine trying to squeeze two pumps down in there. I had a hard enough time getting the damn supra tt pump in there.

almost all parallel setups i've seen had check valves. did you take industrial hydraulics

if one pump goes out, and there is no check before they T into a single discharge line, the pressure may go through the outlet and back out the inlet of the downed pump, losing pressure.... It all depends on design of pump. If it has some fail-close design it could be fine.. This is my main concern.

If you have one pump and it goes out... your car just shuts off, alright.

If you have two pumps and one goes out, and you dip in pressure, your engine will lean out... which could be a disaster

I'm just not sure what others have done... Or would just a larger pump be better.


Modified by sepulchralx at 9:42 AM 2/15/2009

[Kansei240sx]

Instead of going a for a parallel system, have you thought of doing an inline circuit?

[Cjmartz2k]

I've been running two walbro's in parallel for over a year with no problems. I think for most people who have enough hp to require two or more aftermarket pumps, if one goes out, check valve or not, motor goes bye bye.

[Kansei240sx]

A residual check valve is something that would be a needed/good idea because even if you aren't driving it hard, and a pump goes out problems and disruption in flow can arise.

[PhenomR33]

Ive also run the dual walbro with a 2 way joint going to the outlet on the assembly for 3 years, no probs

[Cjmartz2k]

You would WANT a disruption in flow during normal driving if one of the pumps gives up the ghost. That way you know there is a problem before you step on it. Unfortunatly, you usually don't notice anything until it's to late. That's probably the biggest argument against 2 pumps is a single well "let you know" when it dies, but you can't tell with 2 pumps until it's too late.

And BTW, if by inline you meant two Walbro 255HP's for instance, that won't flow more than 1 walbro.

[sepulchralx]

I'm not sure putting two pumps in series will get max efficiency out of the pumps. I think the pump upstream of the first will be only 50% of efficient yet pressure will still rise.... THen the problem comes with adapting the discharge of one to the filter end of the other... And if it falls off, **** could happen.

Anyways, how do you guys mount your secondary pumps... lay them in the tank??? Thats what i really want to know.

[Sil240]

If I were u, I would keep your walbro or whatever in-tank pump you have.Use it as a lift pumpThen look in to a surge tank and a in-line Big pump.

[Darius]

almost all parallel setups i've seen had check valves. did you take industrial hydraulics

if one pump goes out, and there is no check before they T into a single discharge line, the pressure may go through the outlet and back out the inlet of the downed pump, losing pressure.... It all depends on design of pump. If it has some fail-close design it could be fine.. This is my main concern.

If you have one pump and it goes out... your car just shuts off, alright.

If you have two pumps and one goes out, and you dip in pressure, your engine will lean out... which could be a disaster

haha dude. I do more hydraulics than anybody on this whole f**king web board, so let's get that out on the table. Your idea of being able to run one pump if the other goes down is fine if you are looking for redundancy of single operation.

Cjmartz2k is right that you WANT to know if you lose a pump so you don't blow the motor up. If it leaves you stranded, who gives a $hit. I'd rather be stranded with a faulty fuel pump than stranded with a boat anchor for an engine.

And running walbros in series is retarded. Nobody needs 130+ psi of fuel pressure at the regulator unless they're running 80+ psi of boost or running 2mm fuel lines. Regardless, it still only flows what one walbro flows.

[eh?]

Run both Pumps in parrallel, use check valves and use Fuel pressure switches. Obviously you'll need the check valves with that set up. Since you have the EMS you can configure it to run high boost only when both pumps are above the desired fuel pressure at each line. It's an easy concept if you are paranoid about running dual pumps.

[Darius]

You can wire in pressure switches to the EMS?! Man, the flexibility of that system is making me want to ditch my PFC.

[sepulchralx]

You can wire in pressure switches to the EMS?! Man, the flexibility of that system is making me want to ditch my PFC.

haha, do it, then we can chit chat about it.. Btw, what size injectors are you running?

[Darius]

Only 650cc, but that is to approximately match the supra tt flow at the boost I want to run. I'll have to do a major fuel upgrade next winter.

[eh?]

You can wire in pressure switches to the EMS?! Man, the flexibility of that system is making me want to ditch my PFC.

There about 1000X more things you can do with the aem vs a pfc . I ditched the pfc/datalogit 4 years ago. But what I'm talking about is just using the high/low boost switch function of the aem. Just using a switch, relays and pressure switches you can do that. Basically you'd need a ground at the high boost switch and both pressure switches to raise the boost limit. Or you can just set the pressure switches in series and they will be the boost swicth Or if you want you can even set the second pump to turn on at a certain rpm or psi with the output functions.

[sepulchralx]

Do

There about 1000X more things you can do with the aem vs a pfc . I ditched the pfc/datalogit 4 years ago. But what I'm talking about is just using the high/low boost switch function of the aem. Just using a switch, relays and pressure switches you can do that. Basically you'd need a ground at the high boost switch and both pressure switches to raise the boost limit. Or you can just set the pressure switches in series and they will be the boost swicth Or if you want you can even set the second pump to turn on at a certain rpm or psi with the output functions.

Do you tune your car yourself? I really want to be self-sufficient and not have to rely on anyone to tune... Know of anything good besides the aemforums that could teach me the basics of fuel map and ignition timing?

[WhatsADSM]

Do

Do you tune your car yourself? I really want to be self-sufficient and not have to rely on anyone to tune... Know of anything good besides the aemforums that could teach me the basics of fuel map and ignition timing?

There are lots of good books on the subject. Even your local Barnes & Nobels will typically stock them. My suggestion is to start with a good book, or a tutorial from one of the EMS providers. Honestly the internet has probably just as much good info as bad info.

[BoostFab]

most dual pump setup i have seen are dual feed line straight to the rail and regulated by the FPR. of course; if your high powered setup were tuned utilizing that much volume, and one pump goes out, the definite risk is blowing your motor during a race LOL.

[eh?]

Do

Do you tune your car yourself? I really want to be self-sufficient and not have to rely on anyone to tune... Know of anything good besides the aemforums that could teach me the basics of fuel map and ignition timing?

Yes, tuning a mild (less than 500whp) setup is easier than most make it seem. You already have a base map which is the hard part. Read the aem forums for boost comp and read the aem EFI basics manual and also Freshalloy has a very good thread about tuning in the "best of" section.

[Beerdoh]

Just get one big a** fuel pump, lets hassel in my opinion.