04-02-2009, 11:32 AM
[quote=blazinchuck]
Im worried about that. I just find it hard to believe i need to run 2 pumps...what about a holley blue or black...surely that can work by itself???
QUOTE]
Don't be scared of the two pumps. It's not a "need" but a "purpose built system"
A single HP pump will work but you must keep the pickup submerged in the fuel cell all the time. This is easy to do with a full tank. But if you run it low, get off camber and the pickup sucks air, engine will stall. That's the problem you said you had with the Toyota. That is the why you need the accumulator for what you are building. Even if you suck some air out of the tank, the accumulator has enough gas to keep the engine running long enough to get back to normal. OEM EFI fuel tanks and tanks the Bronco vendors sell are baffled and mount the fuel pump in the lowest point of the tank minimizing the effect of fuel sloshing around. But even those tanks were not built or designed to be doing what you building.
The low pressure feeding directly into a high pressure pump without the use of an accumulator in between is just a waste of hose clamps.
For what you are building ( a badass rock buggy) I would use an accumulator. LP pump transfer from the fuel cell, keeps it full, even if the tank is low and the pickup is sucking air some of the time. Then the HP pump then circulates fuel from the accumulator to the EFI and back into the accumulator. Don't return the HP back to the fuel cell or you are defeating the point of the accumulator. That maximizes the fuel capacity in the accumulator from just seconds to minutes of fuel capacity.
It also minimizes the amount of HP line you need to run and have handy in a emergency. The LP pump can use any fuel rated rubber, but the EFI hose is $$$.
A single f250 Pump on the frame can be done but it must be lower than the fuel cell pickup. A HP pump is a pusher and not a puller. And any time it sucks air you will lose pressure at the injectors and the motor will stumble.
The f250 HP pumps and LP pumps are cheap and you can get them at any parts store. Important if you are away from home and you have a problem. An exotic HP pump from summit or Jegs could cut a trip short if you have to wait for a replacement.
Just my 2 cents.........
Im worried about that. I just find it hard to believe i need to run 2 pumps...what about a holley blue or black...surely that can work by itself???
QUOTE]
Don't be scared of the two pumps. It's not a "need" but a "purpose built system"
A single HP pump will work but you must keep the pickup submerged in the fuel cell all the time. This is easy to do with a full tank. But if you run it low, get off camber and the pickup sucks air, engine will stall. That's the problem you said you had with the Toyota. That is the why you need the accumulator for what you are building. Even if you suck some air out of the tank, the accumulator has enough gas to keep the engine running long enough to get back to normal. OEM EFI fuel tanks and tanks the Bronco vendors sell are baffled and mount the fuel pump in the lowest point of the tank minimizing the effect of fuel sloshing around. But even those tanks were not built or designed to be doing what you building.
The low pressure feeding directly into a high pressure pump without the use of an accumulator in between is just a waste of hose clamps.
For what you are building ( a badass rock buggy) I would use an accumulator. LP pump transfer from the fuel cell, keeps it full, even if the tank is low and the pickup is sucking air some of the time. Then the HP pump then circulates fuel from the accumulator to the EFI and back into the accumulator. Don't return the HP back to the fuel cell or you are defeating the point of the accumulator. That maximizes the fuel capacity in the accumulator from just seconds to minutes of fuel capacity.
It also minimizes the amount of HP line you need to run and have handy in a emergency. The LP pump can use any fuel rated rubber, but the EFI hose is $$$.
A single f250 Pump on the frame can be done but it must be lower than the fuel cell pickup. A HP pump is a pusher and not a puller. And any time it sucks air you will lose pressure at the injectors and the motor will stumble.
The f250 HP pumps and LP pumps are cheap and you can get them at any parts store. Important if you are away from home and you have a problem. An exotic HP pump from summit or Jegs could cut a trip short if you have to wait for a replacement.
Just my 2 cents.........