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where to mount fuel pump?


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having trouble deciding where to mount my fuel pump. i know i need to mount it as close to the fuel tank as possible but where exactly? also i just hook up the rubber hose coming from the fuel tank to the fp and then the other end to the metal fuel line that goes to the engine bay?

 

 

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Good thing I checked.. this is for a KA motor in a 310 right??? This should be in your profile so a fuel pump for an A series isn't discussed.

 

Yours will be a high pressure pump for the EFI. The metal line isn't designed for this but I wouldn't have any problem using it. Make sure the clamps ahead of the pump are adequate for the garden hose pressure. The tanks in the 310 are high above the rear end which is good as the pump should also be mounted as low as possible to take advantage of gravity feed from the tank. Fuel pumps are great at pushing but suck at sucking. No pump made, no matter how powerful, can draw fuel vertically over about 30 feet so vertical lift is to be avoided. Other than that, mount outside the car for cooling and to lessen the sound and place where road debris wont's damage it and it won't scrape on anything.

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Good thing I checked.. this is for a KA motor in a 310 right??? This should be in your profile so a fuel pump for an A series isn't discussed.

 

Yours will be a high pressure pump for the EFI. The metal line isn't designed for this but I wouldn't have any problem using it. Make sure the clamps ahead of the pump are adequate for the garden hose pressure. The tanks in the 310 are high above the rear end which is good as the pump should also be mounted as low as possible to take advantage of gravity feed from the tank. Fuel pumps are great at pushing but suck at sucking. No pump made, no matter how powerful, can draw fuel vertically over about 30 feet so vertical lift is to be avoided. Other than that, mount outside the car for cooling and to lessen the sound and place where road debris wont's damage it and it won't scrape on anything.

 

Not too familiar with the 310's, or KA's for that matter, but regarding pumps in general~

 

Mechanical diaphram pumps are indeed designed, and operate well, sucking fuel, as they have backflow valves (usually spring/puck, or possibly reed) in them making every stroke positive flow.

 

Electromechanical pumps are typically vane or gyrotor design- having designed clearances between moving parts for lubrication/friction/heat expansion/etc.. This clearance does not create a 100% positive flow, and allows a bit of bypass to occur- making them location-sensitive. Optimum e/m pump (not the electric motor- but the pump guts themselves)mounting shoud be at or slightly below the bottom of your fuel supply. This takes maximum advantage of Mother Nature's capillary action, and reduces the possibility of losing pump prime after sitting for any length of time.

 

Fuel pressures in general terms are:

mechanical pumps- up to about 9psi

TBI setups- 12-20psi

Portfuel setups- 20+ up to 45-50 (depending on system, mods, etc.)

 

In addition to PSI one must consider fuel flow in GPM as well. If your 310 had a smaller motor it's very likely the 1/4" fuel line will restrict flow for the larger KA~ resulting in reduced performance under load and/or at higher rpm's. This reduced flow can cause the injectors to fall into 100% duty cycle while trying to keep up with the O2 signal~ wearing on them over time. Of course if you're carb'ed then it'll just fall flat on it's face, people will pass you by, point, and laugh..... Let's not let that happen~ the whole point of a motor swap, right?

 

P.S.~ if your KA's injected (or gonna be) leave the old line in place for a return line....

 

Peace~

Scott

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glad I found this. I finished my k swap only 521 and I'm having n issue with this. looks like the pump I not too good at pulling the fuel from the tank. wonder if I use a fitting on the bottom of the tank to feed the pump will help? that way it won't have to pull from the top. sorry I jacked ur thread man.

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glad I found this. I finished my k swap only 521 and I'm having n issue with this. looks like the pump I not too good at pulling the fuel from the tank. wonder if I use a fitting on the bottom of the tank to feed the pump will help? that way it won't have to pull from the top. sorry I jacked ur thread man.

No worries yes use gravity to feed yer pump that's what I did I mounted it as close and low to the tank for best performance

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That bolt in the bottom is for draining. I wouldn't use it for a feed as it's to easy to hit something on the road and rip it off. The tank line is fine and although it has to rise vertically up and out, it also drops down on the outside and this cancels it out. Mount the pump lower than the tank or as low as you can safely. Pumps can push, no problem, but they suck at sucking.

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Avoid any restriction between tank and pump. That filter will never survive 40 PSI do not use ahead of the pump. Get the stainless steel ones.

i use the filter for the fuel injected 280z on my z series engine and my pump works well at drawing through the filter and its a 44$ mr. gasket pump for 4-7 lbs. no problems yet. but i can imagine how it would be better not to restrict flow. back to the point, the stainless filters are really nice. i would recommend using the one found on stock 280z's. it seems high quality

 

 

 

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