Try these...attached. The first one is hard to see, move your mouse over it and it will click. Diagram A and Diagram B. I'm no artist.

 

look at this chart and it might explain itself. this is not the stock pump we have but it will be similur map.



the stock pump by itself is expected to pump 60+psi for us boosted guys. lets say 65psi you can see it will flow about 55gph. now lets say it only has to feed another pump 2feet away and it only has to use 5psi to do that. you can see where the flow just went up to 82pgh. the new inline pump will have a higher flow rating than the stock pump at 65psi. lets say it has a flow rating of 80gph at that presure. you can see how the stock pump can feed it that much fuel since it is only at 5psi and the new inline can up the presure since it is a higher flowing pump.

hope that makes some sence.

 

So the addition of an inline effectively increases the output capacity of the stock pump by decreasing the distance the pressure has to be maintained? Did I get it? If this theory holds true, couldn't one add another inline pump (2 total +the stock) and increase pressure even more? Probably blow a fuel line but I'm just testing my thought process. The less distance a pump has to maintain its pressure the higher pressure it can maintain, right?? So the stock is now pushing harder and the line will not go dry and the inline is pushing at 255lph which will keep my fuel pressure where it needs to be....

 

no, but close. that 65psi isn't from the lines. it is from the injectors. if you take the line off at the motor and just let the pump freeflow there is probably only a 5psi load on the stock pump from the lines and it would flow that high 80+gph.

the stock pump only needs to feed the new pump wich will only take a few psi to get the fuel to that pump. since it is not working nearly as hard it will pump more fuel based on that chart.

with 2 new external pumps(in parallel i assume) you would be trying to draw fuel thru the stock pump at a rate faster than it could pump. the stock pump would be a restriction at that point. the same would apply if you put a really big inline on there. but the basic $130 inline is a good match for the stock pump.

 

Got it. So if I install the 255lph inline pump I got from Magnuson (I assume it's a Walbro) I should not have anymore fuel pressure issues with my 42# Ford (48#GM) injectors? Is there any need at all for the Kenne Bell Boost-A-Pump to be installed onto the inline or stock pump? I don't see why I should need it. I am only going to be making 500/550 at best. You know, half what you make

 

i dont know what pump that is. i do know a gss340m is good for 600+rwhp without a boost a pump. i would use some nice and fat wire to feed it with just to keep the voltage drop to a minimum. at least some number 12 but 10 would be better.

in my last truck i ran into the 11's with just an inline pump. probably close to mid 11's but i never got to the track after turning it up. seems like i was in the 10-11psi range with a 100shot on a 6.0 and was not running out of fuel yet.

 

Well 9 psi and a 50 shot is the most I'm gonna see so I should be good. I guess I'll keep eyeballing that fuel pressure gauge until I get a wideband.

 

do your self a favor and get a wideband now. it makes tuning soo much easier.

 

what if you put an aftermarket high flow pump intake and put a high flow pump inline? would that be able to feed more than the stocker and an inline?

 

not sure on that one but if it does flow more it wont be much more. if you are going to use 2 good pumps like that it would be best to put them in parallel. you will get a ton of fuel then.