All you hardcore guys that have built a small fuel cell to hold race gas for your wet nitrous kits please speak up.

I've got an empty battery (think display model) that I cut the bottom off and the innards out of. I'm going to relocate the battery to the rear and mount this "dummy" battery with the fuel cell in the stock battery location. I'm having a custom alluminum fuel cell made and need some info.

First off, is there a certain thickness that the alluminum must be? NHRA or just plain old common sense? We were going to use 1/8" thick alluminum plate.

Also, I want to run the appropriate size AN line out of the fuel cell, but can't get a consistant answer. Some say it must be -8an, some say -4an is ok. I plan to only run maybe 200 hp worth of N2O, but I'd like to plan ahead and make sure it can flow enough for 300 hp worth. We are going to weld in an alluminum bung in the left rear corner so I can run the supply line right down to the inside of the frame rail.

I have also been told that a return style system would be best, I guess there is less of a pressure drop and therefore easier to tune? What size lines do I need for that? And will there be enough pressure for the return line to push the fuel back into the fuel cell if the fuel level in the fuel cell is higher? I think we can manage to have the return line go into the top of the fuel cell, but I'd like to have all the knowledge I can.

I've also been told I need to add a jet to reduce the amount of fuel returning to the fuel cell... does this make sense?

Also, the normal fuel cell cap from Jaz (or whatever brand it is) has a vent in it. I don't think venting the high octane fuel into the engine compartment is a good idea so I was going to epoxy this vent closed. Is there a certain type of epoxy I should use? I'm not sure if certain epoxies are better for use around fuel. We are going to add a vent to the system and I was thinking of a pressure regulated vent such as the stock one on the Camaro fuel tank system. We are going to build a small "box" for the vent that will stick up a bit from the top of the fuel cell so the fuel level will never be as high as the vent so no liquid fuel should ever escape... So we would run a rollover shutoff valve to a tube down to the vent in the fenderwell or under the front bumper or someplace safe.


Thanks again for any and all help you can provide.

 

Triangle Engineering quoted me $179.99 for a modified version of their 3 gallon cell to mount up in front where the battery is located.

If you go to LS1Tech.com and look for a pic of Reckless's setup, you will see exactly what their cell modified looks like. You will also find a link to his webpage which has detailed information and pics of his setup.

Dave

 

there is a "drag" car here in az *3rd gen* that has a 1 gal fuel cell where the charcoal canister goes.. im going out there this weekend.. ill try and get info/pics on how he did it.

 

Below is the link to the webpage I was referring to earlier.

Direct Port Supplementary Fuel System with Front Mounted Fuel Cell

Hope this helps,

Dave

 

I'm abit partial to the fuel systems I've put together.

FUel Cell


There is a post down the board by NOStang that I made a reply about Bypass fuel systems vs. Deadhead regulators. Just think about this, if you need to put a restrictor jet in the return line, does that necessarily tell you that you want to use a bypass regulator in the first place. If you were to run a bypass regulator place the return at the top of the tank as you mentioned, this will help keep air from the sump in the bottom, and alleviate any problems as you mentioned.

On the vent, Not sure why you'd need to get real fancy here. You should be able to use the vent on the cell, so long as it is ran higher then the cell itself, you can put the open end anywhere you like.

Good luck! You're on the right track!

 

Thanks for the response and the pics/links guys. Keep them coming if you find anymore.

About the fuel vent and getting fancy. I have that same fuel filler/cap as in those pics, and that small circular silver thing on top is the vent. I don't want that venting into my engine compartment.

So I was going to block it off and run another vent tube. Or is the vent in the cap pressure regulated so if I run another vent straight out the vent in the cap will never work since no pressure will build up, right?

I'm going to go search for that other link you stated about return style fuel systems.

But what is the bypass jet used for? This is what doesn't make sense to me.

But the above link with all the pics and descriptions was a big help, so thank you. That is very close to what I already had in mind. However mine will fit into a battery and will be "hidden."

Thanks again guys.

 

So how much horsepower are you running thu the stock -4an lines, Brian? 300hp? more?

Dave

 

That is part of my point Dave. Do you mean the stock fuel lines on the car? Or the stock -4an nitrous line that came/comes with most nitrous kits?

I figured a -4an line would support at least 300-400 hp worth of nitrous since it supports that much of just a motor... but I've been told different by many folks, and all of these folks have run a custom fuell cell/fuel system already...

Anyways, KTamez... I couldn't find that link you mentioned... can you be more specific?

 

Yeah, I meant your stock fuel lines. I get the concept that big mongo fuel lines seem cool, but then I look at that teeny little jet in there...

dave

 

I've thought the same thing... Hence my search for the truth

I think maybe the thought of larger fuel lines being better for this setup maybe for direct port which you would be feeding two fuel solonoids and using a LOT of fuel.

However... some people (me included) would assume it takes more fuel to make X amount of horsepower with nitrous then it does to make the same X amount of horsepower NA.

However I know this not to be true from what "people in the know" have said, not to mention articles online and in magazines.

 

here is the thread that Kurtis was referring too.

Nostang 96Z

 

The vent in the cap itself is really worthless. Cap that off, leave it as it is, doesn't matter. Its not going to spill fuel though, so I wouldn't sweat it. You need another vent, 6AN in size (most premade tanks have something built-in for this) should suffice. This is the one I was saying to run the hose off of.

The restrictor jet in the bypass line is to keep the fuel line from basically emptying the fuel directly back into the tank, so it has fuel pressure on the solenoid itself.

 

Thanks for the link, RacinLT1

KTamez... Ok, good to know the vent in the fuel cap is useless, but will it vent anything? I'm not sure how big a deal it is, but I would rather not have high octane fuel vapor venting inside an engine compartment.

So we will run a -6AN vent line off the top of the fuel cell and run that down to a bulkhead fitting under the car (to keep the vent tube secure outside of the vehicle.) Do I need to run one of those "loop de loops" in the fuel line though? You usually see them in large fuel cells in the back of pickup trucks and trunks of cars, etc.

About the bypass jet. Thanks, that explanation did clear things up some. So your saying do NOT run a bypass, right?

Either way I think I'll have the fuel cell built with an extra bung for a return line if I ever choose to go that route.

As another tip I've picked up from a local street racer... He ran two bungs out the side of the fuel cell, one at the top, one at the bottom and connected them with some clear line. So he can tell how full the fuel cell is without opening the cap... Neat idea.

BTW, if my fuel cell holds 1 gallon how many runs will that last me about? I know there are a lot of variables such as run time, HP shot, fuel jet, etc, etc. But any guistimates? Figure I'll be running 200-250 hp at the wheels.

Also, what is the easiest way to figure out how many gallons or percentage of a gallon my cell will hold? I can figure out volume, but don't know the conversion to liquid...

As always, thanks for your time and knowledge.

 

... I'm waiting for the discussion about octane

Dave

 

Um, run the least amount of octane you can without pinging/knock.

I figure I may end up with 110 or higher in the fuel cell (unleaded of course from off shore racing boats...)