Dual pumps and Regulator adjustment with boost ref
Thread Starter
Launching!
Joined: Feb 2012
Posts: 263
Likes: 50
From: IL, USA
Dual pumps and Regulator adjustment with boost ref I'm running dual 450lph pumps with a 8an feed and 6an return thru an Aeromotive regulator. The second pump is set to come on at around 5 psi with a pressure switch. The regulator also has the boost reference hose connected.
How would I go about adjusting the base fuel pressure that I need (58psi) on this setup? Do I need both pumps on?
How would I go about adjusting the base fuel pressure that I need (58psi) on this setup? Do I need both pumps on?
I run same pumps, same regulator, same fuel line sizes, on my E85 fueled car, fwiw.
210# injectors.
Although, i run both pumps on, full time, and see absolutely no negatives doing so.
My fuel pressure would spike, when 2nd pump was boost referenced. Mine is and was easier to dial in with both pumps on, full time
I had heard, or read, that the Walbro 450's didn't like higher pressures, so I run my base fuel pressure at 45psi.
Setting fuel pressure should be done with the vacuum/reference hose removed.
210# injectors.
Although, i run both pumps on, full time, and see absolutely no negatives doing so.
My fuel pressure would spike, when 2nd pump was boost referenced. Mine is and was easier to dial in with both pumps on, full time
I had heard, or read, that the Walbro 450's didn't like higher pressures, so I run my base fuel pressure at 45psi.
Setting fuel pressure should be done with the vacuum/reference hose removed.
Thread Starter
Launching!
Joined: Feb 2012
Posts: 263
Likes: 50
From: IL, USA
Yeah Chris1313, who's pump assy I'm using said it's fine to run both full time so I think I'm gonna do that. Car is also a non DD anyways. Thanks for the heads up on the base pressure, I will try that when we get ready to retune it. 
Some say the fuel gets overheated with both pumps on. That is not what I have experienced.
I have staged pumps on a Hobbs. I dry tested it by turning on the main pump, set pressure, then manually activate the second pump by shorting across the Hobbs switch while observing pressure. It jumps one psi. Which when under load during a pass becomes invisible.
Also should note I’m -8 feed and return.
Maybe think of it this way. Double the flow, all that fuel needs to bypass into a smaller fuel line. The pressure spike is caused by the smaller return line. I learned that 30 years ago when I built the fuel system on my car when it had an NA rat motor in it.
With the exception of much larger pumps now, the system is still the same.
Ron
Also should note I’m -8 feed and return.
Maybe think of it this way. Double the flow, all that fuel needs to bypass into a smaller fuel line. The pressure spike is caused by the smaller return line. I learned that 30 years ago when I built the fuel system on my car when it had an NA rat motor in it.
With the exception of much larger pumps now, the system is still the same.
Ron
Thread Starter
Launching!
Joined: Feb 2012
Posts: 263
Likes: 50
From: IL, USA
I would never run two 450s full time especially if it's driven on the road for more than 30 minutes at a time. With a good regulator you won't even see the pressure spike when the 2nd one turns on.
Trending Topics
Thread Starter
Launching!
Joined: Feb 2012
Posts: 263
Likes: 50
From: IL, USA
I'm using an Aeromotive fpr btw... LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo