Dual walbro Wiring!
Dual walbro Wiring!
07-04-09, 02:42 AM
#3
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Sorry I don't have an answer to your questions. I simply wanted to share some knowledge that most people don't seem to know.
Dual pumps are a bad idea. If one dies you will still have the needed fuel pressure at low speeds but when you get hard on it the pressure will drop, leaning the engine out and resulting in detonation. I've heard of more then a few high horsepower engines being turned to scrap due to this.
Dual pumps are a bad idea. If one dies you will still have the needed fuel pressure at low speeds but when you get hard on it the pressure will drop, leaning the engine out and resulting in detonation. I've heard of more then a few high horsepower engines being turned to scrap due to this.
07-04-09, 10:36 AM
#4
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The stock wiring does not suck, it's just old and you're expecting it to power more then twice the amount of pump it was designed for. The stock wiring was designed for a 180/200HP car, not a 400+ HP car.
Wiring two pumps is exactly the same as wiring one pump. Use a relay switched by your standalone from a fuse 12V source off of your aux fuse box. Run a nice thick wire down to the fuel pump area (12 gauge or 10 gauge). Use a bulkhead passthrough to get it into the fuel tank on the pump flange then split the wire inside and connect the pumps in parallel.
Wiring two pumps is exactly the same as wiring one pump. Use a relay switched by your standalone from a fuse 12V source off of your aux fuse box. Run a nice thick wire down to the fuel pump area (12 gauge or 10 gauge). Use a bulkhead passthrough to get it into the fuel tank on the pump flange then split the wire inside and connect the pumps in parallel.
07-04-09, 10:41 AM
#5
Sorry I don't have an answer to your questions. I simply wanted to share some knowledge that most people don't seem to know.
Dual pumps are a bad idea. If one dies you will still have the needed fuel pressure at low speeds but when you get hard on it the pressure will drop, leaning the engine out and resulting in detonation. I've heard of more then a few high horsepower engines being turned to scrap due to this.
Dual pumps are a bad idea. If one dies you will still have the needed fuel pressure at low speeds but when you get hard on it the pressure will drop, leaning the engine out and resulting in detonation. I've heard of more then a few high horsepower engines being turned to scrap due to this.
07-04-09, 11:55 AM
#7
Sorry I don't have an answer to your questions. I simply wanted to share some knowledge that most people don't seem to know.
Dual pumps are a bad idea. If one dies you will still have the needed fuel pressure at low speeds but when you get hard on it the pressure will drop, leaning the engine out and resulting in detonation. I've heard of more then a few high horsepower engines being turned to scrap due to this.
Dual pumps are a bad idea. If one dies you will still have the needed fuel pressure at low speeds but when you get hard on it the pressure will drop, leaning the engine out and resulting in detonation. I've heard of more then a few high horsepower engines being turned to scrap due to this.
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07-04-09, 11:58 AM
#8
The stock wiring does not suck, it's just old and you're expecting it to power more then twice the amount of pump it was designed for. The stock wiring was designed for a 180/200HP car, not a 400+ HP car.
Wiring two pumps is exactly the same as wiring one pump. Use a relay switched by your standalone from a fuse 12V source off of your aux fuse box. Run a nice thick wire down to the fuel pump area (12 gauge or 10 gauge). Use a bulkhead passthrough to get it into the fuel tank on the pump flange then split the wire inside and connect the pumps in parallel.
Wiring two pumps is exactly the same as wiring one pump. Use a relay switched by your standalone from a fuse 12V source off of your aux fuse box. Run a nice thick wire down to the fuel pump area (12 gauge or 10 gauge). Use a bulkhead passthrough to get it into the fuel tank on the pump flange then split the wire inside and connect the pumps in parallel.
07-04-09, 01:39 PM
#10
what do you define as 'big' ? I'm not saying this to hassle your in any way. I'm just curious about your setup and whether it really warrants this. Both myself and J-Rat on this forum are running T04R's (67mm inducer) with single pumps just fine. He's making high 500s with a single Walbro pump on stock fuel lines. I'm using a single Supra pump with 6AN hose (clamped the stock hardlines) routed in series like stock. I run 15psi with no issues. Is this a 700whp drag car? A show car with all shiny bits?
There's nothing wrong with duel fuel pumps, but it's easy to spend way more money on a fuel system than you need and then not have that money for other important things on the car like the interior.
I have my car wired like the second diagram. The trigger for the relay comes from the factory circuit opening relay (stock pump wire).
There's nothing wrong with duel fuel pumps, but it's easy to spend way more money on a fuel system than you need and then not have that money for other important things on the car like the interior.
I have my car wired like the second diagram. The trigger for the relay comes from the factory circuit opening relay (stock pump wire).
07-04-09, 01:44 PM
#11
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True, but if a single pump dies the car simply wont run, where as with dual the car runs well enough to get you into trouble. I know lots of people run duals and even in some cases triples with no problems, but I personal would rather just run a larger single pump and have the piece of mind.
07-04-09, 01:54 PM
#13
^ go to carquest and ask for a 4 or 5 pin 30amp/40amp Bosch relay. Or use a factory headlight relay from a parts car or whatever (that's what I use). I wouldn't use the radio shack relays, I have seen many of them burn out.
Last edited by arghx; 07-04-09 at 01:55 PM. Reason: Bosch
07-06-09, 12:06 AM
#17
i hear people running xxx amount of HP on single pumps but thats not for me. to each there own. I would rather run 2. guess ill give you a little run down.
to get the car running ill be using a HX35w, Then switching to a HX40 with a 18cm, then if i can find a diff hot side i will be running a 42r...,Meth, 94oct, 1600 primary, 1680 secondary, microtech, a/w IC...umm no my car isn't a drag car, its a sunny day driver. Yes it's shiny, Yes it's Clean. could it win a car show im sure depends on were. It has bling. It has bumps and 3/8 fuel line.
to get the car running ill be using a HX35w, Then switching to a HX40 with a 18cm, then if i can find a diff hot side i will be running a 42r...,Meth, 94oct, 1600 primary, 1680 secondary, microtech, a/w IC...umm no my car isn't a drag car, its a sunny day driver. Yes it's shiny, Yes it's Clean. could it win a car show im sure depends on were. It has bling. It has bumps and 3/8 fuel line.
07-06-09, 12:11 AM
#18
Just go to the junk yard cut some out of a car. grab many there usefull. all it is is a relay nothing to special. try to get the ones that.....The relay plugs into and the wires run from that. If you just go and pull relays from a box then all you have is a relay and you have to solder to the relay and if it ever burns up you have to un solder and re-solder the new one on.
07-06-09, 10:49 AM
#20
True, but if a single pump dies the car simply wont run, where as with dual the car runs well enough to get you into trouble. I know lots of people run duals and even in some cases triples with no problems, but I personal would rather just run a larger single pump and have the piece of mind.
07-07-09, 09:00 AM
#23
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I can't believe that people are actually suggesting junkyard relays. Seriously, good relays with a holder are like $10 at an auto parts store. Don't rely on junkyard parts which may have been sitting for years in water. Even if they look good, the wires can be corroded inside.
I just raided my local junkyard for GM fan connectors because the ones the auto parts store sells are poor quality (the seal rots away in a year). I picked up 10 of them, all looking good. When I got them home I found that 7 of them had wires that had turned to powder. Totally useless.
One pump versus two pumps will always be a debate and there are pros and cons to both. But since one Walbro is good to 500HP or so, why the need for two? There are higher quality pumps on the market with capacity for a lot more flow. Aeromotive, Mallory and Holley all make nice pumps.
I just raided my local junkyard for GM fan connectors because the ones the auto parts store sells are poor quality (the seal rots away in a year). I picked up 10 of them, all looking good. When I got them home I found that 7 of them had wires that had turned to powder. Totally useless.
One pump versus two pumps will always be a debate and there are pros and cons to both. But since one Walbro is good to 500HP or so, why the need for two? There are higher quality pumps on the market with capacity for a lot more flow. Aeromotive, Mallory and Holley all make nice pumps.
07-07-09, 10:39 AM
#24
^ I've never had any problem with the OEM rx-7 headlight relay or whatever that rx-7 4 pin relay is that I'm using. but that came off a friend's parts car that was not sitting outside.
you do have to be careful with the made-in-China cheap relays. When i had an electric 6 port setup on my nonturbo they used to burn out all the time. When I switched to Bosch I never had a problem.
you do have to be careful with the made-in-China cheap relays. When i had an electric 6 port setup on my nonturbo they used to burn out all the time. When I switched to Bosch I never had a problem.
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