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1G Bosch 044 install?

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Two 255LPH HP pumps WILL flow more fuel than one 450.

Edit: I knew it was more, but wasn't sure HOW MUCH MORE..
This is conservative / to be safe. Looking at a couple flow charts and cross-referencing:

At 12 volts, two 255's flow ~350lph, that's ~50lph more than a single 450 @ ~70psi (~26psi boost pressure) - which flows ~300lph @ 70psi

12 volts, @ ~80 psi (~36psi boost), Two 255's flow ~300lph. One 450 = ~275lph

The higher the voltage, the pumps start doing A HELLUVA LOT better. But I wanted to keep this conservative.

Edit again: Note - this is for Walbro part #'s GSS341/GSS342 for the 255's and #F9000267 for the 450. If you want me to upload the charts I referenced, I can do that.
 
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What are your IDCs with the 044 inline with the 450?
I'm gunna be taking the car out for some testing tmrw to see if I made some hedway, I always plan the weekend in advance. I only get two weekends a month free so i have to plan accordingly. Ill be sure to keep everyone updated.
 
At 12 volts, two 255's flow ~350lph, that's ~50lph more than a single 450 @ ~70psi (~26psi boost pressure) - which flows ~300lph @ 70psi

12 volts, @ ~80 psi (~36psi boost), Two 255's flow ~300lph. One 450 = ~275lph

I'm not understanding how your math adds up. What base fuel pressure are you using for your math? And what flow charts are your referencing?
 
No problem. For the math, I'm using a base fuel pressure of 43.5 - I know these cars are a couple psi different, but 43.5 is what I'm used to, and it's super easy to calculate with being a multiple of 14.5...
Either way though - fuel flow at what pressure the pump is at is what we care about.

The 450 flow chart I'm referencing is straight from Walbro's website.


The 255 flow chart is also posted on their website, but it's in gph and they didn't any math to help US. Which is a crock... So I googled and came up with 1 gallon per hour = 3.78 liters per hour AND cross-referenced charts and data from multiple sources.
-Real street's tests
-Super street's tests
-Radium's fuel pump tests

I did the math quick and it def needs gone over again (will probably edit the post today or tomorrow), but it's pretty solid.
 

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What are your IDCs with the 044 inline with the 450?
Decided to do some more testing while I wait to hear back from jacks for the dogbox. Went with the full blown hanger. My idcs are in the 90s at 37 psi on e85 with the walbro 450 and inline pump. I'm going to see how much if any improvement this makes.
 

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Why do you even need the 044 inline if you have 2 255's in tank? If anything that'd be a restriction? Not understanding that one...

Edit: Does supplying pressure to the intake side raise the floor?
So applying 3 bar to the back side pushes the inline pump to free flow / zero being intake and feed would be equalized?
 
Why do you even need the 044 inline if you have 2 255's in tank? If anything that'd be a restriction? Not understanding that one...

Edit: Does supplying pressure to the intake side raise the floor?
So applying 3 bar to the back side pushes the inline pump to free flow / zero being intake and feed would be equalized?
to be honest I dont know, initially i had the walbro 450 in tank, added the inline and saw an improvement. The I added the new hanger with twin 255s. I wanted to do a surge tank, this is why I purchased the 044 to begin with, I had it so ive been testing. Could it be acting like a restriction? Maybe. https://ls1tech.com/forums/forced-i...44-inline-existing-dual-walbros-intank-2.html
 
Why do you even need the 044 inline if you have 2 255's in tank? If anything that'd be a restriction? Not understanding that one...

Because it's not a restriction.

Configuring two pumps (or 3 in this case) in series will deliver the same flow at twice the pressure, hence, plumbing pumps in series is a way to maintain flow at high pressure. The dual 255's behind the 044 simply allow it to sustain its rated flow at high boost. They do nothing to increase the performance of the 044 itself.

Basically, the 2 lift pumps let the 044 operate as optimally as it possibly can. On its own, the 044's flow would drop off significantly as fuel and boost pressure increase. Same with a lone set of in-tank 255's. However, when you couple them all together plumbed in series you can preserve flow at high pressure, working to offset the normal reduction in flow due to high pressure slowing the pump motor.




Lil update, currently have two walbo 255 pumps with the inline 044, The car is now running 8an ptfe aeroquip lines. My idcs have dropped into the 70s....

The dual 255's will definitely move enough fuel to feed the 044. Hopefully, you don't run into the same issue I had with the dual pumps plumbed directly to the feed of the inline pump, though. In that configuration, when my car would get low on fuel (below half a tank) the dual lift pumps would suck the sump dry, since the return from the tank to the sump is too small. This is one of the main reasons I had to add a surge tank. Your 255/044 combo should move less fuel than mine though, so you may be just fine. If you hear the 044 start to get noticably more whiny as your fuel level gets low, you've got an issue.
 
Because it's not a restriction.

Configuring two pumps (or 3 in this case) in series will deliver the same flow at twice the pressure, hence, plumbing pumps in series is a way to maintain flow at high pressure. The dual 255's behind the 044 simply allow it to sustain its rated flow at high boost. They do nothing to increase the performance of the 044 itself.

Basically, the 2 lift pumps let the 044 operate as optimally as it possibly can. On its own, the 044's flow would drop off significantly as fuel and boost pressure increase. Same with a lone set of in-tank 255's. However, when you couple them all together plumbed in series you can preserve flow at high pressure, working to offset the normal reduction in flow due to high pressure slowing the pump motor.






The dual 255's will definitely move enough fuel to feed the 044. Hopefully, you don't run into the same issue I had with the dual pumps plumbed directly to the feed of the inline pump, though. In that configuration, when my car would get low on fuel (below half a tank) the dual lift pumps would suck the sump dry, since the return from the tank to the sump is too small. This is one of the main reasons I had to add a surge tank. Your 255/044 combo should move less fuel than mine though, so you may be just fine. If you hear the 044 start to get noticably more whiny as your fuel level gets low, you've got an issue.
Once again man.... I appreciate your help. You have gotten me through alot of bs.
 
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