Fuel in - out - Fuel cell

[92TealSupra]

Alright I was curious, on the 7m where does fuel flow into the fuel rail? At the FPR, or the dampener near the firewall?

Also when I have my fuel cell, when the return line comes back what does that exactly hook up to the cell or reroutes back into the system?

 

[Slow66]

Fuel goes in the rail back by the firewall, and the return should be plumbed back into the cell. It should be plumbed such that there is a tube inside the cell delivering the returned fuel very low in the cell and not just spraing the returned fuel on top of the fuel in the tank.

 

[92TealSupra]

Ahh fantastic. That helps so much, i was always confused on where it came through. Also that helps me with the fuel cell itself. The way I have my fuel cell there are two AN fittings at the bottom of the tank, I am guessing, 1 in, 1 out, and then at the top there is a 90 degree one which I think is a vent.

 

[Slow66]

No, you shouldn't use the other lower one for the return. An additional hole should be drilled in the top of the cell, a bulkhead fitting placed there, and then a tube placed on the inside of the cell from the bulkhead to deliver the returned fuel low in the tank.

 

[Mischief7m]

No, you shouldn't use the other lower one for the return. An additional hole should be drilled in the top of the cell, a bulkhead fitting placed there, and then a tube placed on the inside of the cell from the bulkhead to deliver the returned fuel low in the tank.

thats right, you definately want it at the top of the cell, and you want to run a hose low in the tank, for one reason that if you have fuel just spraying into the tank, there is the possibility of it developing a static charge...which is no good

 

[IJ.]

What's the difference returning it low through the 2nd feed port on the bottom of the cell or through a top mounted fitting then into a hose?

 

[92TealSupra]

What's the difference returning it low through the 2nd feed port on the bottom of the cell or through a top mounted fitting then into a hose?

I do agree here with IJ. Though I am learning I have see a great set up today and the return was through the bottom, as well as the feed. So I think I will get the fuel pump soon, if I do choose one that let's say had a max psi of 45, would I need a fuel pressure regulator?

- also at idle whata the cars fuel pressure?

- What does the pressure rise to under load? I am sure this depends on how much power your car produces. I am talking about stock though, and I will have to raise the pressure to put more fuel into the car because the injectors are stock and can no longer put a higher volume in, only a Niger pressure, I just need to know because if I get a high pressure pump I need to control it.

- Now for the 5-9 psi~ pumps, does this mean these are high volume most of the time? I know I need more psi then that

 

[IJ.]

In general you need around 40 psi base pressure with the vacc unhooked from the regulator.

The pressure "should" rise 1:1 with boost

You need a pump that will supply your 40psi base + what ever boost you plan to run ie: 20 psi boost will need a pump that can supply 60 psi.

A lot of the Denso pumps have an internal pressure relief that blows at 60 psi so would be lean at 24 psi boost.

 

[92TealSupra]

In general you need around 40 psi base pressure with the vacc unhooked from the regulator.

The pressure "should" rise 1:1 with boost

You need a pump that will supply your 40psi base + what ever boost you plan to run ie: 20 psi boost will need a pump that can supply 60 psi.

A lot of the Denso pumps have an internal pressure relief that blows at 60 psi so would be lean at 24 psi boost.

Now, the Supra is a rising rate reg, don't I need the vacuum hooked up? What does that do if it is not hooked up exactly? So if I get a pump that pushes 60 psi~, for my stock car I should put it to 40? and then the vacuum controls it from 10 psi through 40?

 

[IJ.]

NO it's NOT a rising rate reg.

I think you're confused here, rising rate reg will "rise" ie: 5psi boost/46psi FP

6psi boost/50psi FP and so on.

The stock reg is 1:1 not rising, 5psi boost/45psi FP 6psi boost/46psi FP.

You pull the vacc line for seeting the base pressure at idle then put it back on.

When you set the 40psi base pressure it will drop by the amount of vacc then engine makes idling so for consistancy you pull the line as vaccum is variable.

 

[92TealSupra]

so 40 psi is good for stock** If I want to raise any amount of psi I added 1:1 like if I wanted an extra 3 Psi~ I would make it 43 psi~?

 

[IJ.]

Yep adding to base = richer subtracting from base = leaner across the entire fuel map with no other changes.

43 is the accepted "norm" and is what most injectors are flow tested at.

 

[92TealSupra]

Yep adding to base = richer subtracting from base = leaner across the entire fuel map with no other changes.

43 is the accepted "norm" and is what most injectors are flow tested at.

I think i will go with the Tsunami. it may be a lot but worth every penny. I found it for 305.00, I will search to see if it is a little cheaper but if not it's okay. Can I use this without a adjustable fpr? or do i need to get one? can the stock fpr adjust properly or is this to much psi?

 

[IJ.]

Buy a reg

 

[tlo86]

What's the difference returning it low through the 2nd feed port on the bottom of the cell or through a top mounted fitting then into a hose?

any answer to this yet?

 

[IJ.]

I wasn't being a cocknose or a smartarse it was a real question if there's a reason not to I'd stop doing it that way!

 

[tlo86]

id like to know the answer too though

 

[Slow66]

Not to say it wont work that way (because obviously it will), but the sumped area of the cell is meant for a nice area for fuel to be removed from the cell. To me, many things work against fuel return in that spot. Gravity, g-forces, a large pump sucking fuel in a port 2" from the return...but then again, my mindset is that of a drag setup of a huge pump, smaller cell, excessive launch g-forces, etc. In a larger cell on a street car with a smaller pump, that doesnt ever launch, i'm sure it would be fine. Maybe I'm just picky (or stupid). Its just not my preferred method of install. Feel free to disagree

cell with return on top...

another....

another..

Do it however you like