Please give opinions on my fuel system
06-07-2009, 09:51 PM
#1
Please give opinions on my fuel system I have a 71 Cutlass with a Magnacharged LQ4 in it at 6psi. The car has an aftermarket tank in it with a intank pump setup. The stock pump with the tank was a Delco EP381 (50gph), OE from a 5.7 Vortec pickup. The car ran ok at 4,300' elevation, where the air was thin. The injectors would start to max right before red line (5,800 rpm, shift at 6,200). I get the car to 630' elevation and it maxes the injectors out quickly, I have not been able to go over 75% TPS.
I picked up two GSS340 with socks and pigtails, planning to make a custom dual pump setup. The problem I am running into is I have 7" from the top of the tank to the bottom, so the whole package needs to fit in a 7"x4" cylinder and I don't think its going to work. I can get one of the Walbro's in no problem, but am concerned it will still not be enough pump for my application. Heres a break down of the system in place:
3/8" feed and return lines, stock truck regulator at the rail, high flow rails, 42# injectors, 50 psi at the rail, 12ga wire on a dedicated circuit to the pump, directly off the battery. 12 ga wire also in the sending unit, pump to connector.
Will this support setup with one GSS340 support 500rwhp?
I picked up two GSS340 with socks and pigtails, planning to make a custom dual pump setup. The problem I am running into is I have 7" from the top of the tank to the bottom, so the whole package needs to fit in a 7"x4" cylinder and I don't think its going to work. I can get one of the Walbro's in no problem, but am concerned it will still not be enough pump for my application. Heres a break down of the system in place:
3/8" feed and return lines, stock truck regulator at the rail, high flow rails, 42# injectors, 50 psi at the rail, 12ga wire on a dedicated circuit to the pump, directly off the battery. 12 ga wire also in the sending unit, pump to connector.
Will this support setup with one GSS340 support 500rwhp?
06-08-2009, 11:37 AM
#2
FormerVendor
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One pump should feed about 550rwhp on a boost application with the lines you have. What do you mean by the stock truck regulator? The stock truck reg. is either in the tank or part of the fuel rails on some years?
Nate
Nate
Last edited by Nasty N8; 06-09-2009 at 11:07 AM.
06-08-2009, 11:13 PM
#5
Its is very tight, I had a GSS307 and the EP381 rubber banded together for mock up and the rubber bands, laying flat, caught on the sides of the hole. both pumps will slide in scraping both sides of the hole. Then the sender is in there, its just really tight. Gonna put one in for now, its a direct drop in, I'll see how it does.
06-09-2009, 11:11 AM
#6
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Ahhh You mentioned in your list of parts that you had high flow rails so it through me off. One pump and you lines and rails should feed 500rwhp without a problem much more and I would get that second pump in there...Trust me Lonnie knows how difficult it is we build some very tight dual pump setups for alot of cars and trucks.
Nate
Nate
