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stock fuel tank or fuel cell?


jpuga

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well i have a 75 280z that is getting preped for a rb26 but i dont know if i should install a fuel cell or keep my stock tank? i took the tank out and it had a lot of rust inside and it has a big dent on one side that is 6-7 inches round and about 3 in.deep. if i use my stock tank and get it refurbished will i have fuel stavation issues? im leaning more to a cell but i would like to use the stock filler and not have a big tube in the middle going to the filler and not to mention the fuel smell. the z is going to be a road car and maybe take it out to the track out in famoso. thanks

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I’d say fuel cel. With the stock tank you’ll have to build a surge can/tank, some fuel cels have them built in. Fuel cel also allows for more flexibility in regards to exhaust routing at the back of the car as well.

 

That's my $.02

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if i go with a fuel cell i want use the stock filler on the side and i have searched and all i could find is people mount the filler behind the lisence plate. i was thinking maybe raise the floor a little and lower the cell on the back so i dont have that tube in the middle. i want the rear to look good and clean. any help on that issue thanks a bunch.

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Unless I miss my guess 75's were fuel injected so you can reuse your stock tank. it has the internal plumbing so it should not have fuel starvation issues.

 

There are numerous posts about adding internal sumps and swirl pots if you want some added margin. do a search

 

IMO the problem with fuel cells is just what you have noticed, most of them fill from the top. I personally don't like the idea of opening the hatch to refuel, but a lot of guys seem OK with that.

 

The other problem is weight and fabrication time. It does take some effort to mount a cell, whereas the stock tank has all the mounting stuff already figured out. You will probably find the stock tank weights less than whatever the finished fuel cell plus mount weights.

 

Dual exhaust is good point in favor of the cell. As is safety (if mounted properly). I think costs will favor refurbishing the stock tank.

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Yes, Nissan did baffle the ’75 and ’76 tanks a little better than the earlier tanks for EFI use, but they still have terrible fuel starvation issues during aggressive maneuvers with less than ¼ tank fuel. They aren't much better than a 240 tank. The ’77 and ’78 cars have little nice internal baffling but still suffer from picking up air pockets during aggressive maneuvers when below 1/4 tank. Below 1/8 tank, just mild playing the engine is popping and sputtering from air pockets. The later tanks are larger and shaped much differently, i.e. it would take lots of fabrication to get one in an nearly Z such as cutting out the spare tire well.

 

If you plan to drive your car aggressively at all and want the OE tank, plan a surge can/tank.

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Do people run dual exhaust on the RB's? I wouldn't think so... I would run the a stock tank and a surge tank because the cells are freakin heavy and a good one (Fuel Safe or ATL) is very expensive, and they require a LOT more installation especially if you don't want to fill it out of the hatch.

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I did the fuel cell thing on my early 74 260z rb26 swap. If I did another, I'd stick with the oem tank (baffled or not) and use the metal vapor tank, located on the rear pass side 1/4 panel.

 

I had my vapor tank out and already modified with brazed on AN fittings, which would allow me to plumb the fuel from the oem tank, to the vapor tank, then from the vapor tank to the front of the car to the motor.

 

You pretty much have everything you need already, to make a nice surge pot, that tucks away nicely. Just remove it, modify it with fittings, re install.... :mrgreen:

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These guys have far more experience and know what they are talking about.

Maybe J has more experience. My only experience is recently installing a fuel cell. Never used a surge tank myself, although I know people that have and they seem to work great. One guy was an ex-boss and he raced a Firebird in ITSS and never had fuel problems after installing the surge tank. I was just coming at this from the recently installed a cell perspective.

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With the OE tank, a surge tank of some kind is must, unless you only use the car to drive wine tours. In that capacity, the OE tank is a great way to let the driver know he needs more gas well before he actually runs out.

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... they still have terrible fuel starvation issues during aggressive maneuvers with less than ¼ tank fuel.

 

Too true; I always joked that even though I somehow had TWO non functioning FUEL lights, it didnt matter, since the car told me it was getting low on fuel every time I went through a spirited left turn.. (in other words, any time I made it to a redlight without any bluehairs in front of me :lol:)

 

MY advice would be to drop your stock tank, clean it out, and have someone fab up a sump on the bottom of it to avoid fuel starvation. I like the concepts of keeping things a little more stock than is common around here; but it doesnt sound like you are building a track car it wounds more like a road car. There is no fuel cell that will have the 16 gallon displacement of your stock fuel tank; the complications involving filling up lead me to believe that you would probably be most satisfied with some sort of configuration using the stock tank. You COULD go to the length I suggested, have the tank removed and boiled, and get someone to cut the bottom out and weld in a sump to help prevent fuel starvation, or take the simple method and use a catch can. However, from what little I have gathered regarding your ideas of the car, I would tend to think you would be more satisfied with the stock tank.

 

There are no fundamental "performance" issues with the tank beyond the starvation, and that is easily remedied. in short..

 

........Pros........

stock tank: larger, simpler installation and removal, fills easily

fuel cell: built in anti-starvation, "cool" factor, complies to racing regulations.

 

....Cons......

stock tank: need to integrate some sort of anti-starvation system; SOME engines need larger fuel lines but unless you are going to the moon that should be irrelevant

Fuel cell: have to custom install it, including mounting and plumbing; I doubt you can use stock filler door, cost (greater if you can't fabricate a way to mount it)

 

Anyone have anything to add?

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thank you all. I think that ill stay with the stock tank and save my self some green and spend it on other parts. ill search on how to make the surge tank out of the vapor tank. i saw it a while back just didnt pay attention to it. thanks again.

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I need to go through and figure out how much $$$ I've spent on my fuel cell and parts so far. The fuel cell was around $170 I believe from summit, but I know i've spent another 3-500 in connections, hoses, and other parts to install this cell. I'm not done yet either!

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