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Surge Tank or Fuel Cell


S30TRBO

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I have done some research and from what I've read when converting a 240Z to EFI you need to build a surge tank or swap in a fuel cell.

 

Something interesting I read on this board was that someone said all you have to do is keep a 1/4 tank of fuel in the tank all the time. Is this a fair statement?

 

 

Also while on the subject of fuel is it recommended to place only 1 electric fuel pump outside of the tank after an inline fuel filter? I heard of people running 2 pumps (240Z Turbo), is this a upgrade or a necessity? Is it common to run them in tandem or 1 on the main line and 1 on the return? Do I want to run an additional pump on the return line? Overkill??

 

I plan on running RC 550CC injectors, 1 electric fuel pump, 2 inline fuel filters, 1 AFPR. My target horsepower is 400RWHP. I'm still trying to track down the injector size to horsepower calculator, I'm wondering if 550cc are going to be big enough, any other recommendations? I haven't purchased anything on the fuel side yet..

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Your choice between a fuel cell and a surge tank depends on what you intend to do with the car. If you plan on doing any type of sanctioned competition I strongly recommend a fuel cell for safety reasons. It also helps when trying to get a highly modified car through tech inspection.

 

If its a street car then the surge tank is a cheaper, easier solution. Just make sure the plumbing is well thought out because you're adding some significant points of failure into your fuel system.

 

Regarding keeping the tank 1/4 full: when I autocrossed my 240Z with the stock fuel tank I could run it down to 1.5 gallons and still not have fuel starvation problems.

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Your choice between a fuel cell and a surge tank depends on what you intend to do with the car. If you plan on doing any type of sanctioned competition I strongly recommend a fuel cell for safety reasons. It also helps when trying to get a highly modified car through tech inspection.

 

If its a street car then the surge tank is a cheaper' date=' easier solution. Just make sure the plumbing is well thought out because you're adding some significant points of failure into your fuel system.

 

Regarding keeping the tank 1/4 full: when I autocrossed my 240Z with the stock fuel tank I could run it down to 1.5 gallons and still not have fuel starvation problems.[/quote']

 

Thanks John. For now my 240Z will be used primarily on the street with an occasional trip to the drag racing track. Our local Z club from time to time has sanctioned Auto Cross events that I would like to test the Z performance at.

 

Do you run 1 fuel pump? I'm wondering if one on either side of the lines would help keep constant pressure on the system, or would one be plenty and do the job?

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I don't know much about this but I am pretty sure that some run a low pressure pump and a high pressure pump.

 

 

My Z which I bought with a V* already in it had a mechanical pump and a external electric pump!! I neverknew why and never used it as it was on a switch.

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I have gone with one Walbro 255 pump. That will do! I am hoping to achieve the same power output as you are. Think I'll just use the stock gas tank myself. Will have the pump just after the outlet of the tank, and run -6AN lines to the engine and probably -6AN return line as well. Think I'll only use one inline filter though.

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I used a baffle, pump hanger, and in-tank pump from a Supra (Z31 donor tank will also work good). Pumps are cheaper and there is no starvation at all. I have pics on my web page. I run a cell in my roadrace car, would of done the above if I could weld back then. You will still need a sump or surge tank if you go with a cell. This is if it's EFI. I wouldn't cut up a nice street car to do the cell.

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I've been looking at the same issue. I'm putting the LS1 in a 240 been looking at cells but don't like filling from inside the hatch and I dont weld. Does any one have pic's of their surge tank setup and where have they been mounting them? Engine compartment or other?

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Here's my setup, flowing from the fuel tank to fuel rail: Don't have pics now.

 

1) 240Z tank modified with 3/8" feed. (5/16 stock line used for return)

 

2) Low pressure electric pressure fuel pump mounted in stock location at rear of car.

 

3) AN-6 SS hose mounted attached under body to stock fuel lines feeds surge tank.

 

4) Custom surge tank mounted on the passenger side shock tower.

 

5) EFI pump attached to pass. side frame rail draws from surge tank above.

 

6) EFI pump feeds fuel rail through Fram HPG-1 fuel filter.

 

7) Fuel rail return goes to surge tank.

 

8) Surge tank overflow return goes back to fuel tank.

 

Some might say that the safety of the surge tank in the engine bay is questionable. However, it only sees 3-4 psi. It doesn't hold that much more fuel than the HPG-1 fuel filter. I would be more worried about a 40 psi leak from somewhere else in the fuel system.

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  • 2 weeks later...

Just picked up a set of NISMO 550cc injectors for $500... I also picked up the Walbro GSL392 for $100.

 

Does anyone know where I can get -6 AN barbed fuel fittings? I just got my Aeromotive FPR from Summit and it has no barbed fittings either....

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I ran a bosche 600HP inline pump with no surge tank with a modified pickup in the stock tank. i could not run at the track with less then a 1/4 tank due to fuel sloshing to the back of the tank on launch. it would fall on its nose in 2nd gear. I installed a cell with -8 connections in teh rear of the tank with foam and never had the problem again. It was fine on the street with the stock tank.

 

I plan on running the same cell (summit) with the new tuned rb26 but will have to go with a different pump. Any suggestions by the way. It will be tuned out to a final Hp of aroung 650-700RWHP. and obviously a 600HP pump wont cut it.

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7) Fuel rail return goes to surge tank.

 

 

Hey Sean, do you know if you have any trouble with the fuel heating up when you run the fuel return back into the small surge tank? as this is not giving the fuel a chance to cool down (better off returning fuel straight to the larger fuel tank)

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  • 8 months later...
Here's my setup' date=' flowing from the fuel tank to fuel rail: Don't have pics now.

 

1) 240Z tank modified with 3/8" feed. (5/16 stock line used for return)

2) Low pressure electric pressure fuel pump mounted in stock location at rear of car.

3) AN-6 SS hose mounted attached under body to stock fuel lines feeds surge tank.

4) Custom surge tank mounted on the passenger side shock tower.

5) EFI pump attached to pass. side frame rail draws from surge tank above.

6) EFI pump feeds fuel rail through Fram HPG-1 fuel filter.

7) Fuel rail return goes to surge tank.

8) Surge tank overflow return goes back to fuel tank.

[/quote']

 

I am going for this setup to. Aim is around 500 crank hp on my RB25DET but not sure if I need 1 or 2 pumps between surge tank and engine.

 

What pumps are you high hp guys running?

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I run the following:

 

standard tank feed to Carter 110gph lift pump

-6 line from carter to 1.5L surge tank.

-10 line from surge tank to Bosch 044 motorsport pump

-8 line from 044 to fuel rail

-6 to fuel regulator

standard 5/16 supply line used as return to surge tank

eensy weensy surge tank overflow returns to main tank.

 

My hope was that by returning the fuel line to the surge tank I am only requiring the carter to flow exactly the fuel that was used, which assuming the carter is flowing as much as it can, is enough to supply 6 ~1100cc/min injectors going flat nacker. I think i'm pretty safe.

 

Only time you could get into trouble is if you start it up and go balls out before the carter has had a chance to fill the surge tank.

 

I really don't think you have much option but to run either two pumps in parallel, or a SX fuel pump perhaps? http://force-efi.com/sx.htm Comes with shiny AN fittings too.

 

Here is a pic of all my gear tucked under the back of a standard 240z.

 

fuel-system-mounted_205.jpg

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Hey Sean, do you know if you have any trouble with the fuel heating up when you run the fuel return back into the small surge tank? as this is not giving the fuel a chance to cool down (better off returning fuel straight to the larger fuel tank)

 

There should still be a return line from the surge tank to the big tank, so there should be fuel being circulated between the surge and main tank from the low pressure pump. If the HP return goes to the main tank, then the low pressure pump will have to have even more capacity to ensure the surge tank is alway kept full.

 

Aren't you guys with turbos concerned about a lean condition causing something to detonate and melt?

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The AN Dash Numbering System is a US military standard for hose fittings (AN is an abbreviaiton for Air Corps/Navy) and was developed in the late 1930s to organize military aircraft hardware into a servicewide system of interchangeable parts. The numbering system itslef refers to a flexible hose that is equivilant in flow rate to a metal hard line with an outside diameter measured in 1/16ths of an inch.

 

So, a -6 hose is equivilant in flow rate to a metal hard line 6/16ths (3/8 or 9.5mm) in OD. A -12 hose is equivilant in flow rate to a metal hard line 12/16ths (3/4 or 19mm) in OD. Some people mistakenly state that a -6 hose is a 3/8" hose, but its actually not. Its a hose that flows the same as a 3/8" metal hard line and the OD is actually much larger then 3/8".

 

Hose end fittings, flares, thread pitches, etc. are all standardized in the the AN system. In addition, there are two type of replaceable hose ends, single nipple and double nipple with the single nipple all but obsolete.

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