Issue With Fuel System Design. Need A Little Help.

[Sayajin]

Okay guys. I recently decided that I was not going to be running a meth injection kit in my GTR33 and have decided to go a different route. However I still need a little help with the design.

First let me tell you what I currently plan to run:

I plan to use the stock GTR pump as a lift pump, running to a surge tank, coming out to 2x Bosch 044 pumps then running to a SARD fuel rail. A pretty standard dual pump setup.

Now this is what I want to do:

Run the above setup, however sit on the side next to the surge tank and dual pumps, a 5 gallon fuel cell. I want to be able to store my C16 in this 5 gallon fuel cell.

Here is where the question comes in however. What I would like to do is this if you can picture it, run a Y line, one coming from the stock fuel tank and the other coming from the new 5 gallon fuel cell. Then plug the single end on the Y line into the surge tank. Now here is the big thing. I would like to put some type of valve right at the point where the Y lines becomes a single line that will allow me to open or close one side of the Y line. IE with the valve to the right, the part of the Y line that goes to the fuel cell is closed and the fuel pumps only get fuel from the stock tank. Conversly, when the valve is to the left, the part of the Y line that goes to the stock tank is closed and the pumps get fuel from the fuel cell.

Get what I mean? Now I dont know if this can be done, but if so I would LOVE to. This would allow me to walk to my trunk turn the valve and have access to whichever fuel I want to run. Then I can walk back to the cabin, run the engine a bit to make sure all of the original fuel is out of the lines, and then change the fuel map to the map for the other fuel.

Now here are my questions:

1. Can this be done? I mean do they make the Y line and the valve necessary to run it this way?

2. About the surge tank, does the surge tank actually store a large amount of fuel? Or does a small amount of fuel just go into the surge tank before it hits the fuel pumps?

The reason I ask this is becuase lets say the surge tank stores 1 gallon of gas. That would mean once I turn the valve, I need to drive the car for say 8-10miles in order to empty the pump gas that was in the surge tank and lines and start getting the C16 in the lines. Or does only a bit of gas actually stay in the surge tank and I can turn the valve, drive a little bit to empty the lines and then be running the C16?

Those are my main 2 questions regarding this setup.

So what do you guys think? Thanks for all the help in advance!

-Sayajin

[GeeTR]

Hey Sayajin,

Would suggest a diagram of what your describing. A thread on setting up a system to run duel fuels and maps would be interesting.

Having to wait for the surge to empty would be a pain though. Might have a think about it tonight

Good luck!

M

[Sayajin]

Okay, here is a crude diagram explaining what I am trying to do. Forgive me for its lack of complexity, im not the most creatively inspired person in the world.

Edited to show return lines

-Sayajin

Edited April 11, 2007 by Sayajin

[Craved]

dont fuel cells already have built in surge protection?

if so, just put your Y pieces after the surge tank tapping off the feed from the surge tank. that removes the issues with removing the fuel from the surge tank.

[Sayajin]

dont fuel cells already have built in surge protection?

if so, just put your Y pieces after the surge tank tapping off the feed from the surge tank. that removes the issues with removing the fuel from the surge tank.

The surge tank is not really for the fuel cell, but for the stock fuel tank. I am using the stock GTR fuel pump as a lift pump to pump fuel to the surge tank so that the dual bosch pumps can then pump it to the fuel rail.

So I have to have the Y line before the surge tank.

-Sayajin

[WogsRus]

yeah it's preatty easy to do, basically you just need a slenoid valve, these are available at most electrical automotive workshops, bosh part suppliers, and best bet is PETROJECT.

You may require two selenoid valve, one on each incoming line.

In regards to how long it will take to get the new fuel through, well propably quite a bit, my car ran for 2 minutes on the fuel in the fuel rail allone. i would expect that it would take about 10-15 minuts to empty the fuel in the swirl pot and the fuel line.

YOUR BIG problem will be that the return fuel needs to go to the tank as well, so that means eventualy the fuel will mix down eventually.

There is no way you can stop this from occuring.

[Craved]

The surge tank is not really for the fuel cell, but for the stock fuel tank. I am using the stock GTR fuel pump as a lift pump to pump fuel to the surge tank so that the dual bosch pumps can then pump it to the fuel rail.

So I have to have the Y line before the surge tank.

-Sayajin

true, but you still need another pump in the fuel cell as a lift pump.

why use the surge tank at all for the c16 if you dont need it

also need some kind of valve for the return as Wogsrus mentioned

[Sayajin]

Hummm...

Question. In that diagram, are the lines you drew in supposed to come from the stock tank, which they are, or from the new fuel cell?

Also if I run those lines directly to the dual fuel pumps, how would that work? I mean as far as having those coming directly to the pumps and also have the lines from the surge tank run to the pumps?

Thats a good note about the fuel mixing because of the return line. I never thought about that.. As far as the valve for the return, I suppose I can add one of the same valves on those and keep it closed when I want to swap fuels.

-Sayajin

[Craved]

Hummm...

Question. In that diagram, are the lines you drew in supposed to come from the stock tank, which they are, or from the new fuel cell?

Also if I run those lines directly to the dual fuel pumps, how would that work? I mean as far as having those coming directly to the pumps and also have the lines from the surge tank run to the pumps?

Thats a good note about the fuel mixing because of the return line. I never thought about that.. As far as the valve for the return, I suppose I can add one of the same valves on those and keep it closed when I want to swap fuels.

-Sayajin

haha whoops - yeah the twin lines should have come from the cell not the stock tank

you would need a valve on both sides of the Y (before the twin pumps) to stop any vacuum effect from the dual pumps. this effectively removes the surge tank from the equation when running from the cell.

[Sayajin]

haha whoops - yeah the twin lines should have come from the cell not the stock tank

you would need a valve on both sides of the Y (before the twin pumps) to stop any vacuum effect from the dual pumps. this effectively removes the surge tank from the equation when running from the cell.

Humm... thinking about it I think your method would be ideal. It would just be a matter of setting it up.

I dont understand 100% of it so I am hoping you can clarify a few things for me.

One, if we were to do it and connect to the surge tank, would I need a lift pump inside of the fuel cell to put the fuel in the surge tank? I sure hope not!

Two, if we were to connect the fuel cell directly to the twin pumps, I am assuming that I would not need a lift pump correct?

Three, as far as the design you speak of, if I were to run the lines directly from the fuel cell to the dual pumps, how would the connections work?

The fuel pumps would be connected directly to the surge tank. So in order to run the fuel cell to the pumps directly, I would need to put 2 more Y connectors there. One end coming from the surge tank and the other end coming from the fuel cell. There would need to be a seperate Y connector for both fuel pumps. Then add the valve there right before the pump to decide which fuel source it pulls from. Then I would need another Y connector at the fuel rail return portion. One to return back to the surge tank for the pump gas, and the other to return directly to the fuel cell for the C16. I would of course need another valve there to decide which return line it uses.

Is that correct as far as the setup you have described? And can it be done? I mean can you run fuel lines directly into the pumps and not have them pull from the surge tank directly?

I will try to get a diagram of what I mention above later, I only have paint here at work and its inadequate for what I am trying to describe.

Thanks for the help!

-Sayajin

[Craved]

Humm... thinking about it I think your method would be ideal. It would just be a matter of setting it up.

I dont understand 100% of it so I am hoping you can clarify a few things for me.

One, if we were to do it and connect to the surge tank, would I need a lift pump inside of the fuel cell to put the fuel in the surge tank? I sure hope not!

Two, if we were to connect the fuel cell directly to the twin pumps, I am assuming that I would not need a lift pump correct?

Three, as far as the design you speak of, if I were to run the lines directly from the fuel cell to the dual pumps, how would the connections work?

The fuel pumps would be connected directly to the surge tank. So in order to run the fuel cell to the pumps directly, I would need to put 2 more Y connectors there. One end coming from the surge tank and the other end coming from the fuel cell. There would need to be a seperate Y connector for both fuel pumps. Then add the valve there right before the pump to decide which fuel source it pulls from. Then I would need another Y connector at the fuel rail return portion. One to return back to the surge tank for the pump gas, and the other to return directly to the fuel cell for the C16. I would of course need another valve there to decide which return line it uses.

Is that correct as far as the setup you have described? And can it be done? I mean can you run fuel lines directly into the pumps and not have them pull from the surge tank directly?

I will try to get a diagram of what I mention above later, I only have paint here at work and its inadequate for what I am trying to describe.

Thanks for the help!

-Sayajin

1 and 2 -- most fuel cells have thier outputs on top of them, which means they will require a lift pump also, check will fuel cell makers on price and whats included - you may be able to get one with it istalled - also look into running a fuel level guage off this so you dont run out.

3) see pic attached - it matches your description .. as for can it be done ... well you will need to work out a vavling system that will allow this as i havent really seen one that will.

have a chat to places like motorsport connections in seven hills to see if they have something from speedflow etc that will do this for you.

[Sayajin]

Okay guys.

So over the past few days I have done a little more R&D and this is what I have come up with.

This SHOULD be the final design for my twin fuel source fuel system. I think this is the IDEAL way to do everything.

The MAIN benfit of this is that I am able to bypass the surge tank when using C16, so I dont have to wait for the surge tank to empty when I want to switch to C17, and conversely dont waste 1.9L of C16 when I switch back to pump. I just need to let the fuel get out of the rail and the lines and viola!

There is one big HOWEVER in this setup though, I would need the valves to be 3 settings valves:

Left Open

Right Open

Both Closed

That way I can close the lines as necessary to purge the system. This would be ideal as I only need 2 valves. One in the trunk with the fuel system, and one under the hood at the rail. If I cant get valves with all 3 settings then I would have to double that number and get 4 individual valves.

On a good note however, most fuel cells made over here in the USA have the fuel feed at the bottom, so I wont need ANOTHER pump to act as a lift pump. Check it out: http://static.summitracing.com/global/imag...um-291205_w.jpg

Viola!

So what do you guys think? Any comments or suggestions?

-Sayajin