Fuel Return? - LS1TECH

Log In 


Fueling & Injection Fuel Pumps | Injectors | Rails | Regulators | Tanks

Fuel Return?

Reply
 
Thread Tools Search this Thread
Old 05-12-2007, 01:48 AM   #1
TECH Enthusiast
Thread Starter
iTrader: (8)
 
dixonk's Avatar
 
Join Date: Sep 2006
Location: Elk Grove, CA
Posts: 696
Default Fuel Return?

At what point or power level should you run a fuel return line?
dixonk is offline   Reply With Quote
Old 05-12-2007, 01:28 PM   #2
8 sec potential, 12 sec slip
iTrader: (50)
 
ChevyChad's Avatar
 
Join Date: Apr 2002
Location: Savannah, GA
Posts: 4,109
Default

I would think anything over 500 rwhp
ChevyChad is offline   Reply With Quote
Old 05-12-2007, 03:30 PM   #3
TECH Enthusiast
Thread Starter
iTrader: (8)
 
dixonk's Avatar
 
Join Date: Sep 2006
Location: Elk Grove, CA
Posts: 696
Default

I'm at pretty much the identical power level as you and still don't have a fuel return. Just want to prepare myself for the new motor. Maybe you can explain to me the reasoning behind it?
dixonk is offline   Reply With Quote
Old 05-12-2007, 03:37 PM   #4
8 sec potential, 12 sec slip
iTrader: (50)
 
ChevyChad's Avatar
 
Join Date: Apr 2002
Location: Savannah, GA
Posts: 4,109
Default

LOL I guess I'm wrong then. I just said 500 because thats what I got away with on my stock engine and single line fuel system.
ChevyChad is offline   Reply With Quote
Old 05-12-2007, 08:20 PM   #5
9 Second Club
iTrader: (10)
 
mikep2002's Avatar
 
Join Date: Apr 2006
Location: Oxford, Chester County,Pa
Posts: 510
Default

Quote:
Originally Posted by dixonk
At what point or power level should you run a fuel return line?
I cant believe you got the amount of power you stated on a stock fuel system or even if you had a Walbro/Ractronics kit. Thats impressive alone. I think at the point of moving up to a 408 with an F1 you gonna need a dedicated system that will run off a MAP sensor. Alot of the stand alone systems are kind of noisey. If you hook up the 2nd pump to run off of the MAP the second pump(external) will only come on when you go into boost. Basiclly my understanding is that it is set up like an alky kit and triggered by boost. You might want to talk to Nate over at Nasty to see if he can set you up. He seems to be a big fuel guy around here. If that doesn`t work there is a particular vendor on another well known forum who sells a kit.
mikep2002 is offline   Reply With Quote
Old 05-12-2007, 11:10 PM   #6
TECH Enthusiast
Thread Starter
iTrader: (8)
 
dixonk's Avatar
 
Join Date: Sep 2006
Location: Elk Grove, CA
Posts: 696
Default

Ya I need to give Nasty a call. Current setup is 2 Walbro 255's running to the fast fuel rails and a kenne bell boost a pump. Pressure stays at 60PSI consistently at 14 PSI of boost with 18 degrees of timing.
dixonk is offline   Reply With Quote
Old 05-13-2007, 08:57 AM   #7
8 sec potential, 12 sec slip
iTrader: (50)
 
ChevyChad's Avatar
 
Join Date: Apr 2002
Location: Savannah, GA
Posts: 4,109
Default

At 14 psi, your fuel should be at 72psi (58+14). That is why you need a boost referenced FPR. Not sure if they make a FPR that does not have a return on it.
ChevyChad is offline   Reply With Quote
Old 05-13-2007, 09:35 AM   #8
TECH Enthusiast
Thread Starter
iTrader: (8)
 
dixonk's Avatar
 
Join Date: Sep 2006
Location: Elk Grove, CA
Posts: 696
Default

Thanks for the great info
dixonk is offline   Reply With Quote
Old 05-14-2007, 12:21 PM   #9
11Second Club
iTrader: (3)
 
Gauge's Avatar
 
Join Date: Dec 2004
Location: Dallas (Richardson), TX, USA
Posts: 1,295
Default

Quote:
Originally Posted by dixonk
Pressure stays at 60PSI consistently at 14 PSI of boost with 18 degrees of timing.
I'm not trying to be a smartass here, I really think I might be lacking some fundamental understanding here... what does spark timing have to do with fuel consumption?
Gauge is offline   Reply With Quote
Old 05-16-2007, 07:04 AM   #10
TECH Addict
iTrader: (11)
 
No Juice's Avatar
 
Join Date: Jan 2003
Location: Minnesota Corn Fields
Posts: 2,284
Default

Quote:
Originally Posted by ChevyChad
At 14 psi, your fuel should be at 72psi (58+14). That is why you need a boost referenced FPR. Not sure if they make a FPR that does not have a return on it.
Ok this maybe a dumb question but why do you need a boost referenced FPR? Why does the fuel pressure need to rise with boost? I'm a fuel noob.
No Juice is offline   Reply With Quote
Old 05-16-2007, 08:05 AM   #11
Pathological Modifier
iTrader: (11)
 
Ryan K's Avatar
 
Join Date: Jan 2002
Posts: 3,626
Default

injectors work off of the differential pressure across the injector. As intake manifold pressure increases, the d/p goes down reducing the flow capability of the injector. SO to maximize what you are getting out of your particular injector the fuel pressure should rise at the same rate as the manifold. If you have 14 psi in the manifold and a rail pressure of 55 psi the injector is really only seeing a fuel pressure of 55-14=41psi.
Ryan K is offline   Reply With Quote
Old 05-16-2007, 08:22 AM   #12
TECH Addict
iTrader: (11)
 
No Juice's Avatar
 
Join Date: Jan 2003
Location: Minnesota Corn Fields
Posts: 2,284
Default

makes sense
No Juice is offline   Reply With Quote
Old 05-16-2007, 09:22 AM   #13
TECH Enthusiast
Thread Starter
iTrader: (8)
 
dixonk's Avatar
 
Join Date: Sep 2006
Location: Elk Grove, CA
Posts: 696
Default

Great learning experience.
dixonk is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are Off



All times are GMT -5. The time now is 03:18 PM.