Intank or inline walbro???
Mar 11, 2009 | 09:15 PM
#11
Theory, behind 2 pumps in-line, or in "series" is that with 2 pumps, they will split the pressure duties between the two pumps. So each pumps is only have to supply about 30psi. Since fuel pumps are flow rated at usually 43.5 psi, but they will flow more volume at less pressure. That is how you get more fuel past the stock pump, with an in-line pump, then just the stock pump could flow by its self. Make since?
Mar 11, 2009 | 09:37 PM
#13
I got a Bosch 044 inline with stocker in the tank. Its only been a month but no problems. I think a big benefit to the intank upgrade is there is no external noise of the inline pump. The down side is you most likely will have to hack up your fuel bucket to make it fit right.....which means you will have to be careful when fuel falls below 1/4 tank.
Mar 11, 2009 | 10:10 PM
#14
TECH Regular
Joined: Nov 2006
Posts: 478
Likes: 6
Theory behind 2 pumps in-line, or in "series" is that with 2 pumps, they will split the pressure duties between the two pumps. So each pumps is only have to supply about 30psi. Since fuel pumps are flow rated at usually 43.5 psi, but they will flow more volume at less pressure. That is how you get more fuel past the stock pump, with an in-line pump, then just the stock pump could flow by its self. Make since?
Mar 11, 2009 | 10:30 PM
#15
Yes, you can't use in-line pumps on 04+ because they are return-less systems with the regulator on the fuel pump in the tank. Your only alternative to upgrading those is to upgrade the in-tank pump, or a voltage booster like a Magna volt. It increases the voltage to the stock pump during boost to increase output.
Mar 11, 2009 | 10:50 PM
#16
I've been rockin' the stock intank and a Magnuson's inline setup for 3yrs. now. No issues whatsoever. I don't think it'll be enough for my future plans, but I'm considering just putting in a 255 intank with the 255 inline. We'll see...
Mar 12, 2009 | 12:24 AM
#17
TECH Regular
Joined: Nov 2006
Posts: 478
Likes: 6
Yes, you can't use in-line pumps on 04+ because they are return-less systems with the regulator on the fuel pump in the tank. Your only alternative to upgrading those is to upgrade the in-tank pump, or a voltage booster like a Magna volt. It increases the voltage to the stock pump during boost to increase output.
Mar 12, 2009 | 08:46 AM
#18
All the 99+ truck fuel systems are regulated at 58 psi, but most fuel components (injectors, pumps, ect...) are rated at 3 bar which is 43.5.
Mar 12, 2009 | 09:08 AM
#19
Theory behind 2 pumps in-line, or in "series" is that with 2 pumps, they will split the pressure duties between the two pumps. So each pumps is only have to supply about 30psi. Since fuel pumps are flow rated at usually 43.5 psi, but they will flow more volume at less pressure. That is how you get more fuel past the stock pump, with an in-line pump, then just the stock pump could flow by its self. Make since?
Fuel pumps are rated for max flow at a given pressure. For instance, a 255lph pump can flow 255 liters per hour at 43.5psi (3 bar rating -- the other sometimes used rating is 5bar). In addition, fuel pumps only supply volume -- they don't create pressure directly. The fuel pressure regulator creates the pressure.
The fuel pressure problem comes from too little volume to support the amount of fuel being delivered by the injectors, so the pressure can't be maintained. Another problem comes up when there is a high demand for fuel (e.g. boost) -- the fuel pump has to work harder (rotation slows down) so volume decreases.
Fixes for these conditions:
1) increase the line diameter of the fuel lines -- a 33% increase in line size will double volume delivered
2) upgrade to a larger in tank pump -- limit goes back to lines vs. how hard the pump has to work
3) add a helper pump in series -- You are still restricted by the flow of the first pump. Yes, there is some degree of added security with the second pump and yes, it will provide a marginal increase in flow over the stock pump alone, but flow testing after the regulator will tell the story here -- it's a night and day difference between a single in-tank 255lph pump and a stock+255 inline. So why do it -- it does help keep the volume the intank pump provides steady by helping the pump keep up with the work load (e.g. the stock pump doesn't have to slow down as much under high demand)
4) 2 in tank pumps -- here there is literally twice the volume hitting the lines and the lines are the restricting factor (without upgraded lines).
Mar 12, 2009 | 09:31 AM
#20
Yes, you can't use in-line pumps on 04+ because they are return-less systems with the regulator on the fuel pump in the tank. Your only alternative to upgrading those is to upgrade the in-tank pump, or a voltage booster like a Magna volt. It increases the voltage to the stock pump during boost to increase output.
Fuel pumps are rated for max flow at a given pressure. For instance, a 255lph pump can flow 255 liters per hour at 43.5psi (3 bar rating -- the other sometimes used rating is 5bar). In addition, fuel pumps only supply volume -- they don't create pressure directly. The fuel pressure regulator creates the pressure.
The fuel pressure problem comes from too little volume to support the amount of fuel being delivered by the injectors, so the pressure can't be maintained. Another problem comes up when there is a high demand for fuel (e.g. boost) -- the fuel pump has to work harder (rotation slows down) so volume decreases.
Fixes for these conditions:
1) increase the line diameter of the fuel lines -- a 33% increase in line size will double volume delivered
2) upgrade to a larger in tank pump -- limit goes back to lines vs. how hard the pump has to work
3) add a helper pump in series -- You are still restricted by the flow of the first pump. Yes, there is some degree of added security with the second pump and yes, it will provide a marginal increase in flow over the stock pump alone, but flow testing after the regulator will tell the story here -- it's a night and day difference between a single in-tank 255lph pump and a stock+255 inline. So why do it -- it does help keep the volume the intank pump provides steady by helping the pump keep up with the work load (e.g. the stock pump doesn't have to slow down as much under high demand)
4) 2 in tank pumps -- here there is literally twice the volume hitting the lines and the lines are the restricting factor (without upgraded lines).
The fuel pressure problem comes from too little volume to support the amount of fuel being delivered by the injectors, so the pressure can't be maintained. Another problem comes up when there is a high demand for fuel (e.g. boost) -- the fuel pump has to work harder (rotation slows down) so volume decreases.
Fixes for these conditions:
1) increase the line diameter of the fuel lines -- a 33% increase in line size will double volume delivered
2) upgrade to a larger in tank pump -- limit goes back to lines vs. how hard the pump has to work
3) add a helper pump in series -- You are still restricted by the flow of the first pump. Yes, there is some degree of added security with the second pump and yes, it will provide a marginal increase in flow over the stock pump alone, but flow testing after the regulator will tell the story here -- it's a night and day difference between a single in-tank 255lph pump and a stock+255 inline. So why do it -- it does help keep the volume the intank pump provides steady by helping the pump keep up with the work load (e.g. the stock pump doesn't have to slow down as much under high demand)
4) 2 in tank pumps -- here there is literally twice the volume hitting the lines and the lines are the restricting factor (without upgraded lines).
The down side to having an inline is when it dies there is a form of restriction and you'll need to limp home. But IMO, replacing an inline BLOWS away replacing an in tank. Granted the rumor is inlines die more so than intanks. Just a rumor I hear.