moshem74 Posted June 16, 2005 Share Posted June 16, 2005 hi to all subaru dl 1993 with hitachi carb. i want to add another fuel pump , inline fuel pump that will sit before the carb under the hood. can i do so? can i put another fuel pump with the one that i already have? do i need to make it work all the time or just when i press down to the end i'll have a swich that will make it work? does this fuel pump need to be stronger then the one that is already in the back - near the fuel tank - under the body? or less stronger ? or have to be exacly the same one? does any one made a project like this ? thank you for your fast answer. moshe. Quote Link to comment Share on other sites More sharing options...
MudisFun Posted June 16, 2005 Share Posted June 16, 2005 Sounds like a mess, but I guess you could do it. To make it work right you would need to find the same fuel pump so that the ratio of stroke will match. You might be able to use any pump by might run a risk of to much or to little pressure in the line between the two pumps. So that you don't over fill the carb/ kill the primary pump using the fuel pump circuit will have to be spliced so when the computer will turn both pumps on and off as one unit. I don't see any reason to do something like this, so what's up? Quote Link to comment Share on other sites More sharing options...
pyromanic Posted June 17, 2005 Share Posted June 17, 2005 Yes, why are you wanting to do this? I have never heard of doing this, and also can not think of a reason to do so. Pyro hi to all subaru dl 1993 with hitachi carb. i want to add another fuel pump , inline fuel pump that will sit before the carb under the hood. can i do so? can i put another fuel pump with the one that i already have? do i need to make it work all the time or just when i press down to the end i'll have a swich that will make it work? does this fuel pump need to be stronger then the one that is already in the back - near the fuel tank - under the body? or less stronger ? or have to be exacly the same one? does any one made a project like this ? thank you for your fast answer. moshe. Quote Link to comment Share on other sites More sharing options...
MilesFox Posted June 17, 2005 Share Posted June 17, 2005 actually older model soobs circa 1982 had the fuel pump under the hood. Quote Link to comment Share on other sites More sharing options...
moshem74 Posted June 17, 2005 Author Share Posted June 17, 2005 hi when you press the gas,if you have a pressure gage,you can see that the pressure is going down when you press the gas hard,that mean that less fuel is comming to the carb. my car has no computer. i want that the pressure will be stronger than what it is now,that never will be less fuel from what it should be,so, i think if i'll add another feul pump and i'll operate it only when i need, it will solve this thing. maby there is a way that i can make more pressure,like put something in the return line of the fuel to the tank or something like that? and then i wont need another feul pump....? thank you. Quote Link to comment Share on other sites More sharing options...
pyromanic Posted June 17, 2005 Share Posted June 17, 2005 If you can find another fuel pump to install inline, why not just replace the one in the rear with the new one? Or am I missing something. Just seems like it would be easier. Good luck Regards, Pyro Quote Link to comment Share on other sites More sharing options...
KStretch55 Posted June 17, 2005 Share Posted June 17, 2005 Adding another pump won't make any difference to a carbuerated system, because the float bowl is basically an unpressurized reservoir that the fuel is drawn from. So, unless you have your foot in it long enough and hard enough to empty the bowl (not likely, since as soon as you begin drawing fuel the float valve will let more in and it's designed to stay ahead of the demand) more pressure will be of no value. As a matter of fact too much pressure could overcome the float valve and cause you lots of grief. Quote Link to comment Share on other sites More sharing options...
moshem74 Posted June 17, 2005 Author Share Posted June 17, 2005 thank you for your answer , got the point. can i put a feul filter on the line that go back to the feul tank = will it make any difference to a carbuerated system, i mean more pressure ,little more...its better then nothing no?....? thank you. Quote Link to comment Share on other sites More sharing options...
bgd73 Posted June 17, 2005 Share Posted June 17, 2005 hi, You're misunderstanding the "pressure" dropping. At slow speeds less fuel "flow" within the same volume (line) pressure will appear to go up. Flowing fuel drops pressure, if pressure stayed UP, while accelerating hard, I'd be worried then. The fuel pump is steady all the time, what we do with the throttle isn't. Quote Link to comment Share on other sites More sharing options...
MilesFox Posted June 17, 2005 Share Posted June 17, 2005 its the same principal as vacuum, when the car is idling it has high vacuum because the throttle is closed. when open, the vacuum drops but yo have volume of flow. so this analogy for the fuel system, you have the pressure when the fuel is stopped up by the carb's float valve, and when the pressure drops, that is because its flowing into the carb and thru the motor its like when you put your finger on the end of a garden hose. plug it up and water shoots out fast but not that much. let go and it pours out freely. wit it plugged and the water coming out faster it may seem to be more water but its coming from the same hose and faucet, so its really not Quote Link to comment Share on other sites More sharing options...
archemitis Posted June 17, 2005 Share Posted June 17, 2005 carburetors have a bowl of fuel, that they draw on when you floor it. more pressure, or more flow wont help a carb. it only needs 2-3lbs to keep the bowl full. Quote Link to comment Share on other sites More sharing options...
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