Fuel pressure drop need HELP
So far I have strair hot wired the pump power and ground side so I know it is getting 14.8 volts. I have the hinson fuel system Walbro 255HP pump with -6 lines for the supply. The tanks is over 1/2 full.
What could be the trouble here guys I have tried everything and it still just falls off at the top end. I think I have a bad pump thats they only thing I can see. Anyone else have something to add here. Oh it is doing this on the Dyno, and driving!
here is the pump before it went in the tank
I was thinking of steping it up to this pump.

Bosch 040
The reg is like this one.

The filter is this size but not this one.

This is the 1st I have heard about the 255 not being able to fill a -6 line???
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I have read go things about it and hence will be using it in my current project.
What ever pump you decide to go with, buy from a seller who can guarantee its 100% Bosch or walbro if you go that route....theirs too many fake chinese pumps that look exactly like the original product.
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The 040 has the same specs as the 044 but the whole bottom of the pump is a screen pickup, rather then an inlet and out like the 044. Its rated to support over 700HP
These are the Bosch specs
040: 100 l/hr @ 6.5bar (94psi)
040: 200l/hr @ 5 bar (72psi)
fuelpumps.pdf
the 040 is recommended for a max of 400hp NA
on the flip side the 044 is very large and a sock( strainer) for it costs $50
Bosch 040 fuel pumps are universal style in tank fuel pump replacements recommended for vehicles exceeding OE specifications. The Bosch 040 fuel pump is one of the only in tank fuel pump that can be compared with the Walbro 255LPH High Pressure series fuel pumps for use in vehicles with up to 700 horsepower.
Bosch 040 Fuel Pump Specs:
Bosch Part Number: 0 580 254 040
Minimum Current: 12 Volts
Operating Pressure: 94 PSI (6.5 Bar)
Minimum Flow @ Outlet: 80 GPH (300 LPH)
Fuel Pump Location: In Tank
High Temperature Reduction: 8 GPH (30 LPH)
Weight: 930 Grams (2.05 Pounds)
Fuel Pump Connections:
Inlet: Open Base
Outlet: M10 x 1.0
Electrical: Positive M6 / Negative M5
http://www.boschfuelpumps.com/
and by your math the 040 still out flows a Walbro 255 casue it is rated at 255LPH at free flow it does not come close to 200 at 4 bar.
As far as boschfuelpumps.com is concerned, not only is their info misleading but, if you purchase a pump from them chances are you will not get it.I even doubt they are still in business
http://www.rx7club.com/showthread.ph...boschfuelpumps
Anyway since Im not helping you much with your original problem I'll cut the yapping. Hope you figure it out.
Last edited by Schitzo; Dec 19, 2007 at 10:35 PM.



