inline fuel pump theory
Thread Starter
Joined: Jun 2004
Posts: 132
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From: NJ
inline fuel pump theory
i was just thinkign the other night about the theory of how a fuel pump works......
intank- fully understandable, the intank fuel pump gets replaced with say a walbro 255 and that is that......
what i do not understand is.....
an upgraded inline fuel pump (say the same one, walbro 255) is installed "inline" with your fuel line under the hood, how does that work????
Are you suppose to remove your original intank fuel pump, or disconnect it....
BUT, if you think about it the inline fuel pump is actually pullin fuel through my stock intank fuel pump.....
Another way to put it.... glass=fuel tank straw=stock fuel pump
garden hose=upgraded fuel pump mouth=motor
glass.....to straw......to mouth......STOCK
glass.....to straw....to garden hose....to mouth....INLINE FUEL PUMP
(No sense.....could only pull as hard as straw would pull)))
glass.....to garden hose....to mouth......INTANK FUEL PUMP
i hope someone understands this and can help me......i am not nuts, and the inline pump came with a kit.....i dont want to have to purchase an intank, unless is have to, please guys focus one the theory we r talkign about about...comments about my anology i guess are ok...
intank- fully understandable, the intank fuel pump gets replaced with say a walbro 255 and that is that......
what i do not understand is.....
an upgraded inline fuel pump (say the same one, walbro 255) is installed "inline" with your fuel line under the hood, how does that work????
Are you suppose to remove your original intank fuel pump, or disconnect it....
BUT, if you think about it the inline fuel pump is actually pullin fuel through my stock intank fuel pump.....
Another way to put it.... glass=fuel tank straw=stock fuel pump
garden hose=upgraded fuel pump mouth=motor
glass.....to straw......to mouth......STOCK
glass.....to straw....to garden hose....to mouth....INLINE FUEL PUMP
(No sense.....could only pull as hard as straw would pull)))
glass.....to garden hose....to mouth......INTANK FUEL PUMP
i hope someone understands this and can help me......i am not nuts, and the inline pump came with a kit.....i dont want to have to purchase an intank, unless is have to, please guys focus one the theory we r talkign about about...comments about my anology i guess are ok...
Honda-Tech Member
Joined: Jan 2003
Posts: 8,132
Likes: 5
Re: inline fuel pump theory (prelude994e)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by prelude994e »</TD></TR><TR><TD CLASS="quote">glass.....to straw......to mouth......STOCK
glass.....to straw....to garden hose....to mouth....INLINE FUEL PUMP
(No sense.....could only pull as hard as straw would pull)))
glass.....to garden hose....to mouth......INTANK FUEL PUMP</TD></TR></TABLE>That's not too bad, but remember any pump has a range of possible flows & pressures. Not just a single operating point. You want the inline booster pump to be kinda compatible with the flow & pressure of both the stock pump AND the needs of the fpr & injectors.
Say the stock pump is you trying to push your stalled car.
Your buddy comes to help, you both push; that's like adding an inline pump. You're both helping each other.
Your other buddy drives up with a tow truck, that's like a BIG in-tank pump. But if you're still hanging onto the rear bumper trying to push, you're just slowing everything down.
glass.....to straw....to garden hose....to mouth....INLINE FUEL PUMP
(No sense.....could only pull as hard as straw would pull)))
glass.....to garden hose....to mouth......INTANK FUEL PUMP</TD></TR></TABLE>That's not too bad, but remember any pump has a range of possible flows & pressures. Not just a single operating point. You want the inline booster pump to be kinda compatible with the flow & pressure of both the stock pump AND the needs of the fpr & injectors.
Say the stock pump is you trying to push your stalled car.
Your buddy comes to help, you both push; that's like adding an inline pump. You're both helping each other.
Your other buddy drives up with a tow truck, that's like a BIG in-tank pump. But if you're still hanging onto the rear bumper trying to push, you're just slowing everything down.
Honda-Tech Member
Joined: Oct 2001
Posts: 4,611
Likes: 3
From: Severn, MD
Re: inline fuel pump theory (JimBlake)
Stock fuel pump flow rates diminish as pressure is increased. Pressure is increased by using a larger restriction in the return line.
If you install an inline pump you are effectively removing the 'restriction' that the stock pump sees and thus is allowed to flow a lot more fuel - so basically, the stock pump becomes a thick straw to supply the inline pump.
If you install an inline pump you are effectively removing the 'restriction' that the stock pump sees and thus is allowed to flow a lot more fuel - so basically, the stock pump becomes a thick straw to supply the inline pump.
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