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Old 02-13-2010 | 09:27 PM
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Default two inline fuel pumps

Guys,
Has anyone ran two inline fuel pumps one up stream for the other? I want to put my old Walbro 255 near the tank and my new aermotive in the engine compartment. I must say, the only reason I want to put it in the engine compartment is because it looks cool and the fuel filters will be easy to access...

Thanks..
Old 02-13-2010 | 09:35 PM
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Someone will correct me if I am wrong but I think you would be better to run a low pressure pump back near the tank and the high pressure pump up front. Reason being is that a low pressure pump primes much quicker and is less likely to be affected by fuel sloshing around in the tank.
Old 02-13-2010 | 10:22 PM
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you dont want to put two pumps inline with each other! but not one in front of the other. if your using a y block you should be fine. you want to have the pumps as close to the fuel tank as possible. they push fuel much better than pulling it.
Old 02-13-2010 | 11:08 PM
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Okay, I was thinking it isn't the smartest thing to do, but why not? Will it cause too much pressure at the pump down stream? Will there be a a void of fuel between the fuel pumps?
Old 02-14-2010 | 12:22 AM
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I have done this and this is my 2cents in it.

I had a stock fuel pump in tank and a Walbro 255LPH in the engine compartment. this was installed "in series" (not a LS1 car)
I was able to make good power 500+hp 550+/- in torque
I did this because, the replacement intank pump at the time was around or over $400

Here are the issues Ive found:
If one pump fails, I could and have run lean because the pump that failed acted like an obstruction in the line. I tested this by shutting it one pump at a time and could just hear the pump whine like there is no tomorrow. It would still run, but not offer enough fuel pressure to support the HP
2nd, Im no mathmatician, but lets say if my OEM pump flows 100LPH and I place a walbro 255LPH unit in series. The Walbro 255LPH will not flow a full 255LPH due to the obstruction of the OEM pump. Figure 200LPH +/- will be the output of the Walbro 255.Although it worked fine in my situation, I would not use it again in that configuration.


I hope this helps....If others think Im wrong, be nice
Old 02-14-2010 | 10:03 AM
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Originally Posted by aixgelo78
I have done this and this is my 2cents in it.

I had a stock fuel pump in tank and a Walbro 255LPH in the engine compartment. this was installed "in series" (not a LS1 car)
I was able to make good power 500+hp 550+/- in torque
I did this because, the replacement intank pump at the time was around or over $400

Here are the issues Ive found:
If one pump fails, I could and have run lean because the pump that failed acted like an obstruction in the line. I tested this by shutting it one pump at a time and could just hear the pump whine like there is no tomorrow. It would still run, but not offer enough fuel pressure to support the HP
2nd, Im no mathmatician, but lets say if my OEM pump flows 100LPH and I place a walbro 255LPH unit in series. The Walbro 255LPH will not flow a full 255LPH due to the obstruction of the OEM pump. Figure 200LPH +/- will be the output of the Walbro 255.Although it worked fine in my situation, I would not use it again in that configuration.


I hope this helps....If others think Im wrong, be nice

I hear you on the second point, but we'd need to know how the pumps are designed to confirm this. I'm trying to imagine what is going on inside the pump; With regard to the pump in the engine compartment, would it be similar to rolling down and hill in first gear, or would it be more like rolling down a hill in sixth gear??

Any comments? Should I just dump the idea and put this beautiful billet red pump on the frame rail and call it a day? I really don't want to do that....
Old 02-14-2010 | 12:37 PM
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From: surry, va
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the pumps will be pushing/pulling against each other if they are inline. if you use a yblock, they will push together. this is how i did mine..

i know what your saying, its a shame that its such a pretty pump to just be hidden. but on a fuel injected motor, the pump is much more efficent as close to the tank as you can get it and as low as possible.



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