my build is getting closer to being driveable and its time to do my fuel system. i already plan on building a custom fuel cell. but i need some advice on cutting the floor out where the back seat was. the car is not getting a cage yet so i was wondering how much chassis strength will be lost if any. im not just gonna cut a hole but build a box over the cell to keep the fuel system out of the driving compartment.

 

there are frame rails on the sides of the trunk
dont cut thoes. just ut inbetween. youll be fine.

 

ok thanks thats what i wanted to hear before i went cutting holes in my car.
anyone elses opinion for safteys sake?, this car will see lots of road course action.

 

I wouldn't cut out a floor, the only time my floor was cut was to put in the cage.

Have you seen NRG tech's fuel cell? fits in stock location, holds 5.1g and still uses the factory fill neck!

Thats what I will be using, just ordered mine and should be here anyday now.

 

i mean i wouldnt reccomend cutting out the entire floor, but a 2x2 square in the trunk is nothing. especially if you have a struct tower brace and the rear bumper rebar in place.

 

Why are you putting in a fuel cell? Its a lot of time and money and doesn't add any performance advantage. Unless your class requires it I'd just use a stock tank.

You're fabricating your own fuel cell? Where are you getting the bladder? Do you mean you're fabricating your own fuel tank? In general that'll be less safe than using a stock unit--especially if you make it out of aluminum (which tends to crack rather than bend when hit).

I'd put the cage in first too, before putting in the fuel cell and cutting out the floor.

I put the ATL fuel cell into the CRX for safety, but I sure as hell wouldn't do it again if I had a chance.

 

i plan on cutting out the area where the back seat was between the framrails, not the trunk

thats nowhere near the size i want. im looking to go larger than stock capacity. i also plan on using the stock fill location

im putting in a fuel cell because i want to and i have the skills, tools, and materials to do so. and yes i mean im gonna fabricate the cell too. the stock tank was accedentialy used to jack up the car at one point in time and its all rusty. plus its already out from when i cleaned up and re undercoated the car. and i just dont want to put the stock tank back in.

the car is not going to be in any class, but may be some day. for now its just gonna be a track day car. it will get a cage next winter i just wanna drive the car fo the summer. im a corner worker at a local road course, so i get to drive when i want. check out the sig for more info on that if you want.

 

I'm not trying to knock you, I'm just speaking from experience--been there and done that.

Okay, it'll cost several hundred bucks in fittings, adds weight, complexity plus you're actually making your car MORE dangerous than stock because stock tanks have been crash tested and are able to deform quite a bit before failing. Real fuel cells have a deformable bladder than can really, really take a beating without failing.

Make sure you get some sort of baffled trap door system or use a scavenger pump with a surge tank or you will have fuel starvation issues. Foam helps with the sloshing, but doesn't solve the issue.

If you ever do have to go racing, you'll have to yank it all out and replace with a real cell, plus put the whole thing in a box, cover the filler neck, etc.

I did mine for safety reasons. Not sure what you're doing it for. I personally don't get it, but knock yourself out!

 

thanks for your concern but im gonna go throught with this. i just like to build stuff and this seems fun

i was planninn on making some internal baffels before i close it up and using a sump on the bottom of the tank

 

ok back to my original question.

how much structial integrity will the car lose from cutting out the area under the rear seat between the frame rails in front of the rear subframe out?

 

Probably a fair bit. What sort of structure are you putting into hold the fuel cell? If you make a nice 'cage' for the cell to sit into and tie that into the unibody it would probably eliminate some of the loss. Spare tire area would be less critical.

 

i was plannin on building somr sort of cage around the cell. was also gonna build a new floor over the cell and add an x brace from the b pillar to the rear strut bar.

finally recieved my materials 4'x8' sheet 3003 series 1/8" thick