greerracing

Here is a quick drawing that i did. I could not figure out how to get it to embed.

Untitled-1 | Flickr - Photo Sharing!
The reason I am wanting a new fuel system is that i want a system that is boost reference-able, a system that does not require me to drop the tanks, and a system that allows the siphon to still work. So here is my idea in a nut shell, I am not for sure it will work or if someone has other ideas please respond. To start i want to drill two holes in the bottom of the drivers side tank, one being a -6 fitting used for a return line and the the other being a -8 fitting. Both lines will run from the tank into the driver side rocker panel where the -8 fitting will feed a Magnafuel MP4302 pump, the pump will then run to a Y fitting in the engine bay. The other side of the Y fitting will be fead by the stock fuel line with a check valve right before the Y fitting. The Y fitting will then feed the boost referenced regulator (-8) mounted to aftermarket fuel rails. The regulator will return to the bottom of the driver side fuel tank. The Magnafuel pump will be activated by a hobbs switch set at 2psi, and the external regulator will be set at 56-57psi. When the pressure of the external regulator rises above the stock regulator the check valve before the Y fitting on the stock fuel line side should keep the intake regulator from being damaged. Basically this system would bypass the stock fuel system when the car makes over 3 psi of boost.

Thanks for reading this and hopefully some of this made sense.

gotjuice?

Very close to the way I did mine. I spliced the factory pump at the rear instead on in the engine compartment and then used the original feed line as the return line. I used the ECS tank fitting so I did not have to tap the tank. I felt it would seal better. You will have to drop the tanks to block off the factory regulator and block off the passenger bypass. I also used check valves to prevent backflow. I have not had any issues with it so far. I used the Magnafuel 4303 pump with a hobbs switch.

greerracing

Why do I have to block off the factory regulator and factory bypass, wont the check valve on the stock fuel line before the Y fitting keep the pressure in the stock fuel system around 58 psi when the external system pressure exceeds the stock system pressure, or do the block offs do something else.

narfdanarf

Without commenting on any other aspects of your plan. The first thing I noticed is that the regulator is on the supply side of the fuel rails which is generally the wrong way to go about it. If it's not on the return side of the fuel rail then there will be a pressure drop from one side of the rail to the other as the fuel is used.

gotjuice?

You will be eliminating the factory pump if you do not use the block off plates. Search, It has been discussed a lot lately. Doug, ECS had a good explanation of how everything works.

Unreal

I don't think you can just block off the factory pump 100% like you want. The internal regulators wouldn't be able to dump all the fuel from the factory pump and it would probably damage the stock pump.

turbotuner20v

look at the a&a fuel kit, it's pretty much the same thing with a smaller pump.

DOUG @ ECS

Thanks.

Search the A&A vrs ECS fuel system thread and a lot of your questions will be answered along with seeing how an incorrectly engineered fuel system is made and sold to the public.

I know I'm biased, but for what we charge for our finished fuel system I personally do not think it's worth the time it takes to reinvent the wheel.

Z06-TT

... put fuel into the rail. then form the rail to a reg and then the return system....

greerracing

I have the upp fuel system right now which works fine but i was just looking for a way to go boost referenced without dropping the tanks, but it looks like i am going to have to. Thanks for all the input.

mourat

Putting a check valve is pointless.

The stock pump already has an internal check valve you can't pump back into it, the check valve is located at the neck of the stock pump and is a pretty good one at that. I have 3 of them beside me.

Otherwise your fuel system would bleed down after shut down if the stock pump didn't have a check valve.

mourat

The only way for you to accomplish this is to run a SURGE tank or block off the stock fuel line and run just an external tank, then the stock pump just runs the stock system.

Surge is best and you dont have to drop tanks Dropping would still be ultimately but completely unecessary.



And if you want to just use what you already have, and go boost referenced only up to 56 psi, so starting point being lower, you could just drop the passenger tank and install an LPE block off.

BoosterClub

The pressure difference will be negligible. The only thing that will affect it will be the resistance in to flow in the lines, but if they are sized appropriately it will be a non issue.

If we were talking about gas, as in state of matter, then yes this would be true.

narfdanarf

To put it simply: you are 100% wrong. Normal fuel pressure regulators control upstream pressure. In the OP's example. as fuel pressure would be required to be increased as boost increases the regulator will shut further to increase upstream pressure which in turn decreases downstream pressure exponentially to the point of almost no flow. This is the exact opposite of what you want in a boost referenced system and defeats the entire purpose of installing a return line. This setup would be worse than stock.

jacked cobra

I did something very close to what you did works great. To test it and see if it works just trick out the pumps to run with the car off and turn the reg up to the amount of boost you are going to run pass base fuel pressure. If it gets to that pressure and holds there your good. Example 58psi base 10psi boost. total 68psi fuel pressure your good. If you want a diagram of my set up pm me its a little different then yours.

Quiky One

As gotjuice nailed in the first response, your basic system you have created will work if the tanks are dropped and you install the two LPE block offs. I would change the way your lines are at the fuel rails and run a front crossover with the feed lines at the rear and the regulator at the front of the drivers side rail.

Here: read this thread http://forums.corvetteforum.com/c6-f...ours-best.html

Doug does an awesome job explaining the system in easy terms. Read post 18, 21, and 29 closely to see why your drawing as is won't work.

x2.

Jason

BoosterClub

To put it simply, you 100% have no idea how a fuel pressure regulator works.

There is no "upstream" and "downstream" pressure. The feed into the regulator is DIRECTLY connected to the output of the regulator to the fuel rails. NOT through any sort of orifice or limiting device like you seem to have decided in your head.

Pressure is regulated by a variable orifice that simply bleeds off excess pressure into the return line. It is partially open the entire time your fuel pump is on. It closes some when there is a higher fuel demand or higher targeted pressure from boost. It opens some when there is a low fuel demand or low pressure targeted from vacuum. It is not inline with the supply and output lines, it is teed in, it does not backup pressure on the supply line in order to effect a change in output pressure.

Regardless of how open or closed the orifice is pressure before and after the regulator are nearly identical. The only variance that may occur is from the restriction of the lines themselves. This is negligible in a system with recommended hose sizes for the flow.

I know it's probably really hard for you to wrap your head around these concepts, but try and actually go do some reading if you still don't get it instead of replying with some half cocked rant.

BoosterClub

Reread what he wrote, he's not talking about the same thing you're talking about with the OEM regulators. He's just trying to say you can't use a regulator on the supply side of a fuel rail, which is 100% incorrect. I would argue is actually the more common placement on other makes and models.

Also, in regards to the OPs "design" it will work, even with the factory regulators in place. The only difference is that when commanded pressure goes above the factory pressure, the OEM fuel pump will start dumping back into the tank rather than feeding to the engine bay. At that point though he has an external pump feeding the engine, and a checkvalve to prevent bleed back through the OEM regulator. It's not great because you lose the flow from the oem fuel pump, but it will work.

One issue will be the passenger siphon though, it needs to see high pressure to operate (it operates through a regulator), and the OP will likely be below that pressure when in vacuum.

mourat

Stock system has two regulators lol, both are capable of relieving pressure since both are tied into the same system, both to the same pump.

greerracing

I would use a surge tank setup and i originally wanted to do this, but I have a UPP twin kit so space is at a very minimum and I haven't figured out a place to mount one yet. If you have any mounting locations im all ears.

Everything I have been reading says my system should work, but wouldn't the syphon still work because base pressure would still be around 58psi or does base pressure decrease with vacuum. Also I could just run the external pump all the time and just have the factory system tee into the return line of the regulator unless somebody sees a problem doing it this way. A magnafuel mp4302 should handle at least 1200rwhp which is more than ill need.