What's Next After You Outrun Your Walbro Drop-In??
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I have to assume that the reason the second pump doesn't kick on until 16psi is so it doesn't overrun the stock FPR at idle/cruise when the engine isn't consuming much fuel.
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I would agree, the stock FPR probably can't handle that much fuel bypass at idle, hence the part time duty of the secondary pump. I've run twin pump setups before, but never had one cycle on and off based on load. Is there no concern about backflow through the pump that is off line during low load conditions?
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I have to wonder if it would make more sense to ditch the pressure switch and run the twins full time with an upgraded fuel pressure regulator.
I'm trying to think about the downside to doing it like this:
a) heating up the fuel?
b) additional expense of an aftermarket FPR
or is the second pump coming on at x psi a non issue with regards to tuning?
another concern, if the second pump dies you'll lean out, if the pressure switch dies, you'll lean out.
I'm wondering if I should do the same setup I did with my stealth FPR + Kenne Bell boost -a- pump.
I'm trying to think about the downside to doing it like this:
a) heating up the fuel?
b) additional expense of an aftermarket FPR
or is the second pump coming on at x psi a non issue with regards to tuning?
another concern, if the second pump dies you'll lean out, if the pressure switch dies, you'll lean out.
I'm wondering if I should do the same setup I did with my stealth FPR + Kenne Bell boost -a- pump.
Last edited by Mellon Racing; Nov 25, 2007 at 07:16 AM.
I am using the Fullblown twin pump assembly, it is a very nice piece and works well. I run twin pumps 100% of the time with -8 Feed & -6 Return, I have an Aeromotive regulator and the car runs with about 45 PSI at idle. I really like this set up as it simplified my original plans to run an external A1000 from a surge tank that the in tank was going to feed. It presented to many places to leak, and I wasn't too happy about running pressurized fuel lines inside of the car! So if you need 2 pumps (500+ WHP) then check out the Fullblown unit...
As a side note.... Fullblown please chime in,.... I want to modify the return of the unit to larger than 1/4 preferably 3/8" or larger, but I would need a new suction manifold to make it work. Has anyone modded this portion of the unit and had success transfering fuel from the other side of the tank?
As a side note.... Fullblown please chime in,.... I want to modify the return of the unit to larger than 1/4 preferably 3/8" or larger, but I would need a new suction manifold to make it work. Has anyone modded this portion of the unit and had success transfering fuel from the other side of the tank?
LJ,
Do you think it would work if the siphon return was drilled 3/8" and then the manifold was made of a brass T and a few barb fittings, is there anything special inside of the plastic siphon?. I never looked at it before I dropped it in the tank.
Do you think it would work if the siphon return was drilled 3/8" and then the manifold was made of a brass T and a few barb fittings, is there anything special inside of the plastic siphon?. I never looked at it before I dropped it in the tank.
Thanks guys, well the problem is the stock siphon piece is very restrictive. You wont be able to get base pressure down past 60ish thats why you have to trigger the second pump to come on later. Im sure you could drill the siphon piece out and still have it work but we have not tested it yet. LJ
edit: just read your install instructions, nice job by the way! So even if you have an aftermarket fuel pressure regulator, the stock siphon piece can still act as a bigger restriction to fuel return back to the tank? So that the fuel pressure regulator isn't really regulating pressure?
Last edited by dubbleugly01; Nov 25, 2007 at 10:31 AM.
Heres a pic of the stock siphon piece. If you look inside from the bottom of it, you would see tha that its a tiny little hole. I dont know if drilling it out would affect it but its something we'll definately try very soon here. LJ
the evo tank is a saddle design. There are 2 fuel compartments ( one on the drivers and one on the passenger). The siphon uses the return fuel to create a suction to pull fuel from the passenger side over the the drives.
