Installed Dual intank 255's
02-06-2006, 11:27 AM
#1
Installed Dual intank 255's I installed my dual intank 255's the other day. I already had the single 255 in the tank. I went with the three port air line splitter and ran it into the stock fuel lines. Still using the factory fuel pressure regulator. Instead of running both pumps all the time, I have a hobs switch turn on the second fuel pump at 3-4 psi manifold pressure. I made a pass through for the extra set of wires for the second pump.
The system performed flawlessly! I made it onto the Dyno the next day, I hooked up a fuel pressure gage to the rail while on the dyno. The Fuel pressure stays almost rock steady at 60 psi the whole pull with no dips or spikes with the second pump fires up.
I didn't take any pictures but I used the pictures I found in here to help make it...
Ryan K.
The system performed flawlessly! I made it onto the Dyno the next day, I hooked up a fuel pressure gage to the rail while on the dyno. The Fuel pressure stays almost rock steady at 60 psi the whole pull with no dips or spikes with the second pump fires up.
I didn't take any pictures but I used the pictures I found in here to help make it...
Ryan K.
02-06-2006, 11:48 PM
#3
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What fittings did you use to connect the airline fittings to the stock fuel rails?
And did you keep the stock bucket?
-B
And did you keep the stock bucket?
-B
Last edited by Blown383; 02-07-2006 at 02:23 AM.
02-07-2006, 08:25 AM
#5
Originally Posted by SRZ
I thought they were 340 pumps? Seems everyone is using 255's though. I ordered 340's. 
Glad it worked flawless for you too. Can't wait to get mine.
Glad it worked flawless for you too. Can't wait to get mine.
those are the same pumps.
they used to call them 255s because they were 255 at pressure.
but everyone else advertises their pumps at unrestricted open flow ratings..
so walbro started to do the same, and calls them 340s.
02-08-2006, 09:48 AM
#7
Originally Posted by MrDude_1
were you getting fuel pressure drop on the dyno before you went to the dual pumps?
I never really dynoed this combination with the single pump. I don't believe that a single 255 is really capable of delivering enough fuel for 650 rwhp through an automatic.
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02-08-2006, 09:53 AM
#8
Originally Posted by Blown383
What fittings did you use to connect the airline fittings to the stock fuel rails?
And did you keep the stock bucket?
-B
And did you keep the stock bucket?
-B
Ryan
02-08-2006, 10:34 AM
#10
Originally Posted by Ryan K
I never really dynoed this combination with the single pump. I don't believe that a single 255 is really capable of delivering enough fuel for 650 rwhp through an automatic.
but i was just curious if you were seeing a high end FP drop off to begin with, and then this fixed the problem, or if it was something you just did and tested without a prior "control" test...
btw, where did you mount your hobbs switch? in the intake plumbing, or to the manifold? if its on the manifold, did you use that little HVAC vac nub in the back, or something else?
02-08-2006, 12:57 PM
#11
Originally Posted by MrDude_1
i wouldnt try it on my car either.
but i was just curious if you were seeing a high end FP drop off to begin with, and then this fixed the problem, or if it was something you just did and tested without a prior "control" test...
btw, where did you mount your hobbs switch? in the intake plumbing, or to the manifold? if its on the manifold, did you use that little HVAC vac nub in the back, or something else?
but i was just curious if you were seeing a high end FP drop off to begin with, and then this fixed the problem, or if it was something you just did and tested without a prior "control" test...
btw, where did you mount your hobbs switch? in the intake plumbing, or to the manifold? if its on the manifold, did you use that little HVAC vac nub in the back, or something else?
Ryan
02-13-2006, 01:09 AM
#12
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Originally Posted by Ryan K
First I have a 98 car so no bucket really. The fittings I uses were 3 barbed 5/16 to 1/4 pipe, 1 3 way air line, 1 1/4 pipe plug, and 1 1/2 pipe to 1/4 pipe adapter. Then used 5/16 hose to connect the splitter to the stock fuel line in the tank. Make sure you use hose rated for EFI pressure and EFI hose clamps (not the worm gear hose clamps).
Ryan
Ryan
Pics? Also what did you do about the wiring for the 2nd pump?
-B
Last edited by Blown383; 02-14-2006 at 01:02 AM.
02-14-2006, 08:18 PM
#14
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I had both pumps wired at the same time with no problems. I did it that way just for peace of mind, meaning if the 2nd pump took a crap I didn't want to find out the hard way. 
Plus it was just easy that way.
Plus it was just easy that way.
02-15-2006, 07:38 AM
#15
Originally Posted by HellRaiser
I had both pumps wired at the same time with no problems. I did it that way just for peace of mind, meaning if the 2nd pump took a crap I didn't want to find out the hard way. Plus it was just easy that way.
Plus it was just easy that way.i mean, it'll run fine until you need the second pump for volume....go WOT under boost and boom... but just driving around, it would act fine since one pump is sufficent.
really, i was thinking about this.. id wire them both seperately, and run a watchdog circuit of somekind.. similar to thoes electric waterpump watchdog boxes.... if one dies then, you'll know before it goes boom.
02-15-2006, 08:14 AM
#16
yep...
Originally Posted by MrDude_1
if one of the pumps die, how do you tell?
i mean, it'll run fine until you need the second pump for volume....go WOT under boost and boom... but just driving around, it would act fine since one pump is sufficent.
really, i was thinking about this.. id wire them both seperately, and run a watchdog circuit of somekind.. similar to thoes electric waterpump watchdog boxes.... if one dies then, you'll know before it goes boom.
i mean, it'll run fine until you need the second pump for volume....go WOT under boost and boom... but just driving around, it would act fine since one pump is sufficent.
really, i was thinking about this.. id wire them both seperately, and run a watchdog circuit of somekind.. similar to thoes electric waterpump watchdog boxes.... if one dies then, you'll know before it goes boom.
02-15-2006, 08:47 AM
#17
Originally Posted by Old Geezer
Yet, another reason to use a single pump, that's sized for the application......
show me a quality intank pump that big, and i'll buy it (along with half the other FI guys)
although, i kinda like this watchdog idea... im still running my single pump setup, but i think i'll tinker with making one anyway...
02-15-2006, 04:32 PM
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Originally Posted by MrDude_1
if one of the pumps die, how do you tell?
i mean, it'll run fine until you need the second pump for volume....go WOT under boost and boom... but just driving around, it would act fine since one pump is sufficent.
really, i was thinking about this.. id wire them both seperately, and run a watchdog circuit of somekind.. similar to thoes electric waterpump watchdog boxes.... if one dies then, you'll know before it goes boom.
i mean, it'll run fine until you need the second pump for volume....go WOT under boost and boom... but just driving around, it would act fine since one pump is sufficent.
really, i was thinking about this.. id wire them both seperately, and run a watchdog circuit of somekind.. similar to thoes electric waterpump watchdog boxes.... if one dies then, you'll know before it goes boom.
02-16-2006, 08:10 AM
#19
Originally Posted by HellRaiser
I would think the fuel pressure would drop a little at idle? That was something I really never thought about. But like you said I would want some kind of warning that the other pump is working before it was to late. I like things simple and the way I did it was simple and worked for me.
one pump is enough to run a LS1 just fine... even one stock TPI pump (they flow less then stock LS1 pumps)
i dont think you'll see a fuel pressure drop until demand exceeds the volume pumped by that one pump.
hmm... im starting to see a need for a product.... something that can monitor the current draw of the pumps and warn you if one fails....
although, you can probly set a adjustible fuel pressure switch to near where your FP is set to, and have a big bright light come on if it starts to drop pressure........
02-16-2006, 03:21 PM
#20
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Originally Posted by MrDude_1
eh, not to scare you, but no.. i dont THINK it would drop at all.
one pump is enough to run a LS1 just fine... even one stock TPI pump (they flow less then stock LS1 pumps)
i dont think you'll see a fuel pressure drop until demand exceeds the volume pumped by that one pump.
hmm... im starting to see a need for a product.... something that can monitor the current draw of the pumps and warn you if one fails....
although, you can probly set a adjustible fuel pressure switch to near where your FP is set to, and have a big bright light come on if it starts to drop pressure........
one pump is enough to run a LS1 just fine... even one stock TPI pump (they flow less then stock LS1 pumps)
i dont think you'll see a fuel pressure drop until demand exceeds the volume pumped by that one pump.
hmm... im starting to see a need for a product.... something that can monitor the current draw of the pumps and warn you if one fails....
although, you can probly set a adjustible fuel pressure switch to near where your FP is set to, and have a big bright light come on if it starts to drop pressure........