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Discussion Starter #1 (Edited)
I have converted over to fuel injection but I really dont feel like trying to make or modify a fuel tank with baffles. I read that you can make something called a surge tank the only thing is that you need two fuel pumps. I was considering buying one of those low pressure fuel pumps you get at autozone or any of the local parts stores and putting it in line right before one of those large injection fuel filters then running a T-fitting to the return line to act as a surge then after that I will have a high pressure 100 psi injection fuel pump going to the intake. Does this sound like it will work at all?
 

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If I follow your post you are going to recycle the fuel back to the filter ahead of the suction side of the high pressure fuel pump. If that is correct, I would think you will biuld a lot of heat in the fuel that way, instead of sending it back to the tank to be mixed with the cooler fuel. ?????? Maybe I don't understand what you are wanting to do.
 

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Discussion Starter #3
I think maybe i need to put the t fitting in before the filter. Im just looking for the simplest way to setup a surge tank. I know it has been done so i know it works. Im going off this diagram so im trying to work out something simpler to help with fuel starvation due to teh lack of baffles in the tank.

 

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That is basically the factory stock setup on my 88 VW GTI. I was amazed at how they set up this. I had to replace a line etc. and couldn't quite understand why they went to all that trouble.
 

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I've been researching this on for a while. Hard to find good information. Even harder to find anyone who knows what you are talking about. Everyone seems to believe that the fuel requirements for EFI are the same as for a carburetor. They are not.

I'm assuming you are using a multi-port system (one injector for every cylinder). First some technical info on EFI systems. EFI pumps are designed to push fuel, not to pull. Because of this, pumps are usually mounted in the fueltank or lower than the tank. The pump feeds directly to the fuel rail. There is a fuel pressure regulator mounted to the fuel rail that returns excess fuel to the tank. There is a vacuum line connected to the fuel pressure regulator. Under light or part throttle conditions, fuel pressure will be about 10 psi lower than at WOT. So on a stock TPI engine, you may have 35 psi at idle (or part throttle) and 45 psi at full throttle (or when vacuum drops). Think of this as the power valve for EFI.
The actual amount of fuel that enters the engine is determined by the pulse width of the injectors. You may have noticed that injectors tick. This is because the internal valve of each injector is constantly opening and closing. The ECM will use a longer pulse (hold the injector open longer) for more fuel or a shorter pulse for less fuel. While all of this is happening, the fuel pump is moving a very large volume of fuel. Which brings us up to our current discussion.
To keep an EFI engine happy, you need a constant large volume of fuel with no air in the system. Most modern cars have an upright tank with internal baffling. The pump is mounted internally at the lowest point. The upright design lets gravity work in your favor. When it is combined with the internal baffling, you can keep fuel at the pump under acceleration and cornering even when the fuel gets low. The problem with retrofitting EFI into an older car (such as a Nova) is that most had flat fuel tanks. With the flat tank, the pick up or pump can be uncovered under hard acceleration or sharp cornering once fuel starts to get low.
In Europe, older cars are retrofitted to EFI for road racing. They came up with the idea of adding an external surge tank (1 gal for four cylinders). (Surge tanks are nothing new. They have been used on prop style planes for a lot of years now.) The purpose of the surge tank is to purge any air from the fuel before it is sent to the high pressure pump & fuel rail. A lift pump will feed fuel from the primary tank to the surge tank. There is a return line at the highest point in the surge tank. Air should rise to the top and return to the primary tank. At the lowest point in the surge tank will be the feed to the pressure pump. (The pressure pump must be mounted lower than the surge tank.) The high pressure pump feeds the fuel rail. The return from the fuel pressure regulator also returns to the surge tank. This should insure that the surge tank is always full. This should also insure that there is always a constant supply of fuel (with no air bubbles) even under hard cornering or acceleration.

Whew! That's a lot of typing. I need a break.:beer:
 

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I had my tank modified by Rock Valley Antiques in '95. I have a 190 LPH Mustang pump in my tank. They added baffling that is attached to the top of the tank. (I specified that I wanted the tank sumped. It wasn't.) The results were OK but not impressive. (I have to keep the fuel level above a 1/4 tank to prevent fuel starvation under heavy throttle or hard cornering.)

I am not crazy about the idea of a surge tank in the trunk and I haven't found a good place under the car. Jeg's is getting $1100.00 for a stainless efi tank. That's a bit out of my current budget. I am thinking about ripping off an idea from the Mustang crowd.



This tank welds into a 12" x 12" hole in the bottom of the factory tank. It would be the new lowest point of the factory tank and would serve as essentially an internal surge tank. Fuel enters this box through two 3/8" holes on the left and right. And with this set up, one fuel pump would get the job done. I posted this idea a while back but my schedule has not allowed me the time to pursue it. I have purchase stainless steel to build my own version of this. (I don't need the external fittings and stainless won't rust.) I plan to mig weld it together with stainless wire. Eastwood sells a kit to replace the sealer on the inside of the steel tank. I was thinking of flowing argon into the tank to disapate any oxygen. (Gas vapor needs oxygen to go boom.)
 

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Discussion Starter #7
Wow the surge tank idea looks much simpler haha. I actually know some people that have done it with success.
 
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