Alright right now i have a walbro fuel pump and am looking at upgrading to dual pumps. I was going to go with the dual supra tt pumps.

From coopers website i would prob be fine with the walbro and supra tt pump combo, yet ive heard of walbro pumps burning up.

any thoughts on this at all?

injectors are 1680 and 850.

Also is it better to Y the pumps together inside the tank or outside?

I know some people have had some disasters with them being Y'ed in tank, but this is just hearsay from what i know.

Thanks for your help guys.
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Doesn't matter where you Y them together, as long as you have check valves between the pumps and the Y.

 

i am going to y mine in tank. and run 2 walbro pumps.
i have heard of them burning up too.. but i say that there is no way both pumps will burn up at the same time.

 

why are you running dual pumps in the first place? What power are you planning to make? The only reason i ask is you may look into going with an external pump instead. Walbros are noisy as hell, especially 2. If your going to deal with that noise might as well get something that flows more, but externals can get pricey compared to the cheap 255's. The dual pump setup i used was 2 walbro 255's Y intank to a brazed an 8 on the lid.

 

Here is how I set up my dual walbros
http://www.banzai-racing.com/efini_dual_fuel_pumps.htm

 

Lots of people run dual pumps and I haven't read of any failures of this type, but...

From a system design perspective, two pumps is sort of dangerous in the event that either of them fails. Let's say each pump meets 80% of your needs. One pump stops working. You drive around for a while, unaware of the failure, since you haven't needed the extra 20% that the second pump provides. Then you do, you run lean, and the engine is dead. And the chance for one of the pumps failing is double what it is for having the pump system fail when you are only running one pump.

Contrast this with having one pump. The pump fails. Your car stops working. You don't need a rebuild.

-Max
one big pump

 

heres a good write up http://www.nopistons.com/forums/inde...howtopic=66911

 

I asked this in another thread but didn't get any replies, thank you for confirming this. Also i think it's been noted before that it's jdm tight yo to have two fuel pumps. But if i'm not mistaken they (usu) run two pumps that are both capable of meeting the needs of the engine to deal with pickup problems and mid-run failures. No sense spending 5k on a rebuild, $X,xxx on go fast parts and then cheap out on fuel delivery imho.

 

Walbro pumps run hot, you just need to keep the gas level above where they sit, so about 1/4 tank. Which is the lowest you should let your gas get to anyway, for obvious turbo rotary related reasons.

I have dual Walbros, I'm just trying to comprehend how to put them together. I had a 30 minute discussion with Ihor, and I came out scratching my head confused as hell...I still don't get it

 

Alright, well after reading this, i still believe two pumps will be needed. even by your calculator max on your site.

you will not always have one pump fail and the other go out and your car go lean. If you wire the pumps correctly and together than they act as one. If one goes out so does the other one. Thus your car will not go lean it will just shut off.

Just like christmas lights used to be. If one bulb went out the whole strand went out. Also it seems to be more of a problem of running lean with two pumps if it is two seperate lines running to the rails instead of one.

Its not total jdm to have two fuel pumps. i think running an external pump will be way too loud and considering this car will not be a track only car, its a must to keep it bearable.

 

which is why you get a fuel pressure gauge in cab.. that way you can see the pressure normally.. and monitor it. i agree with the christmas tree comment too!
chris, your set up looks like it would work very well.

 

The are NOT intended to be flames, but I don't think the two-pumps-because-one-won't-do setup is very well understood. If you don't want to discuss it further, I'm okay with that. However, I see problems with both of the solutions (xmas light wiring, fp gauge) to the one-pump-fails issue as presented so far in this thread.

If you wire like xmas tree lights (in series), each pump will only see 6v. And making a rough guess they they will pump half as much fuel as they would at full voltage, you'd be better off with one pump (same flow, less parts, better reliability)! That's a joke, but it's based in reality. This also assumes that pumps become an open circuit when they fail, which may be true, but I'm not sure that's the predominant failure mode. If there is some better way to wire them so that if one fails they both stop, I can't imagine what it is, without using a controller device with some "smarts". Please describe how to wire two pumps so that they will both stop if one fails, and they both get full voltage.

Will a failure of one pump really show up on a FP gauge in a way that you can't miss? I've had an FP gauge for years, and since the pressure changes with boost/vacuum, it's pretty hard to quickly detect an anomaly. Also, I usually don't stare at my FP gauge when I hit my HP peak and the engine needs the extra X% of fuel. What do you expect to see, and when do you expect to see it, when one pump fails?

My SPA gauges have programmable warning lights that would be great if you could have the light turn on when the pump fails. But how would you program it to come on if and only if there is a pump failure? I could see this perhaps working if you have one of those gauge sets that includes both a fuel pressure and a manifold pressure (boost/vac) gauge, and you can have the FP gauge show only the difference in pressure between the fuel system and the manifold (so it will stay relatively constant). You could program a warning light to come on when the pressure dropped below a certain level in that case.

Perhaps the sound level will be different enough to detect when a single pump has failed. However, it has been my experience that fuel pumps make a variety of different noises based on how full the tank is, temperature, etc. so this might not be a very reliable indicator.

Maybe you could construct a little circuit that would show a warning light if one of the pumps dies. I bet the circuit would be pretty simple for someone with just a moderate amount of electronics knowledge. You could even turn it into a product and make a little business out of it. I'll help you with marketing by spreading FUD about unmonitored dual pump setups.

Running one pump to each rail might actually be better from a what-happens-when-one-fails perspective. If the primary rail pump dies, the car will stop running. If the secondary rail pump dies, the car will fall flat on it's face as soon as you try to boost, and hence you won't break a seal.

-Max

 

well, max, im sure i could come up with some warning light for the fuel system, possibly tie it into the Low fuel light and use that instead. that way its completely stock.
Otherwise i am still open to suggestions on the single fuel pump. If you happen to have a diagram with your current setup that would be awesome. im a very visual person and pictures and drawings.
Another way to hook up the two pumps would be to wire a boost switch, or injector duty switch. As soon as it hits a certain amount of boost the other pump kicks on. Thus you wont have a huge amount of fuel coming on at idle while you are just sitting there. Thus only one pump is running most of the time until it is needed.

Also for everyone that thinks running two walbrows or two supras will give you the flow of 500lph (walbro) and 580 (supra TT) you are wrong. it is at most 1.65 times the amount of one pump. And this is with a well flowing Y. With a Tee at most times you will prob see just a little above the flow rate of one pump. just fyi.

Max you really have me brainstorming about making a system in which there is an indicator light that tells you when one pump dies.

If you have a good electrical system going to your pumps you would not be able to tell much of a voltage increase with one pump shutting off at a high load or even low load. This is saying that you checked your voltages to a tee and made sure you are getting a current flow.

Another way is to wire it so when that fuse does blow out it sends current to an adjacent feed which lights up or turns off a light in the cockpit, or better yet a buzzer that goes off so you know you are losing fuel pressure.

There are a lot of ideas to choose from, im just looking for the most reliable and the not neccessarily the easiest way out.

 

Wow. I am glad a single Walbro will be enough for my car. This dual pump theory is making my head hurt.... and we haven't even talked exact efficiency numbers yet.

 

Ive got the Aeromotive A1000 pump...

 

i really hope that isnt your real grounding point. yes it is attached to the chassis. You might want to strip away some of that paint on the spare tire spot so you can get a better connection.

Otherwise nice setup.

Single outta tank pumps are over my head at the moment. Ive done a lot of research onto the dual pump so if someone like max or anyone else wants to chime in on some details about it. that would be cool.

 

We have done many dual pump setups. Walbro/walbro, nippondenso/nippondenso and nippondenso/walbro. We always Y it out of the tank and each pump gets its own power supply.

Jason

 

I am about to setup my two walbros with a T in the tank, I know Y would be better for flow but I have seen people on the forum use a T, also that Y block with fittings would be $100+. I plan on doing something with a cell eventually, so who knows how long I will keep it this way.

I just need to find a way to get the wires into the tank & seal everything up.

 

I've just got one pump (A'PEXi BNR-32) with stock wiring. And the plumbing is all stock right up until the FPR. The fuel pressure holds for the amount of power the car makes (410WHP). Nice and simple.

-Max

 

i cleaned out my charcoal canister line and each pump runs a seperate line to the rails. a ford starter solenoid pushes fused battery voltage to each pump when (for right now) the stock power wire flips the relay.

i watch things with a fuel pressure gauge in one of flyrx7's speaker pods and i haven't had any problems except for finding out that a K&N fuel filter will restrict the needed fuel pressure past a certain point.

 

hate digging up old threads but a buddy ran a 911 pump in his 680hp awd Eclipse;
Single Pump, $(600 i think), easy install;

If you'd like - I could get some details from him later tonight;