What to do about the gas tank?

[DS 240R]

I've got an 89 I'm modifying for road racing. I always thought the tank on these cars was a horseshoe over the axle under the backseat, but this one is way out back.

Does anyone have a fuel cell in their early S13 or did you put a fe braces around the tank or just leave it as is?

[thx247]

Tank looks like this out of the car...

http://www.turbo240sx.ca/fueltankdropped.jpg

I've seen fuel cells in a few 240's but nothing I would want to run. All were still way out back and just sitting roughly where the spare tire used to be, sitting higher than the stock tank I don't really see the point.

Something like this maybe possible...

http://kingmotorsports.com/images/racing/photos/2003_swc/2003_swc_hatch_3.jpg

http://www.fuelsafe.com/CustomVintageRacingBladders.html has some custom applications worth talking about

[TBreu007]

My 240sx race car has a stock fuel tank with stock supports. It's plenty low and safe. The only negative side effect is a slight change in the car's balance as the fuel runs low. The difference is actually pretty slight...I've had the car on scales when empty and almost full and the change is neglegable. A fuel cell would only put the fuel higher up raising the center of gravity and it would bring the fuel closer to the passenger compartment. With a stock fuel tank, if there was a leak, it would be completely outside the car.
If you're actually planning on racing the car, one of the easiest classes to get into, Improved Touring, does not require a cell.

[DS 240R]

My 240sx race car has a stock fuel tank with stock supports. It's plenty low and safe.[\QUOTE]

The main thing I was thinking about was safety in a rear impact.

[QUOTE=TBreu007]A fuel cell would only put the fuel higher up raising the center of gravity and it would bring the fuel closer to the passenger compartment.

True, but we'd also probably lower the polar moment and there'd be more crumple zone before the tank gets hit directly.

If you're actually planning on racing the car, one of the easiest classes to get into, Improved Touring, does not require a cell.

We are going to be racing in NASA's SE-R Cup and the car will be DET powered, so we will see higher speeds than ITS. NASA doesn't require a cell for this class, but a little more margin of safety is always a good thing.

[DS 240R]

Tank looks like this out of the car...

http://www.turbo240sx.ca/fueltankdropped.jpg

Yup, that's what the tank looks like all right.

Was I just mistaken or is there any S chassis that has the horse-shoe tank below the back seat?

[adamhu]

you guys are missing a prime reason to get a fuel cell..well actually a few...

1=no fuel starvation under high g loads
2=less likely to explode due to being foamed
3=less weight....
4=in the spare wheel well...more protected...more crush area..plus now has 2 times the wall material to penetrate thru..before it hits the bladder
5=in the spare wheel well..slightly closer to center of car

downsides of in the wheel well....
slightly higher up raising C of G

i am in the process of installing a fuel cell have a look..all custom fabbed

http://www.turbo240sx.ca/PERFORMANCE3.html

[turbod240]

The new 240 I just picked up was slighty damaged in the rear and the whole trunk pan I cut out to straighten it as it got pretty rippled. I decided I dont need a spare tire carrier area so as I made my new floor pan I replaced the spare tire area with a custom fuel cell holder and its not much higher than the original gas tank. I am not using my car to race on a track but i thought it would be nice to have a fuel cell to lighten the car up and a few other reasons.

[DS 240R]

...so as I made my new floor pan I replaced the spare tire area with a custom fuel cell holder and its not much higher than the original gas tank...

Sweet! You got any pics?

[TBreu007]

you guys are missing a prime reason to get a fuel cell..well actually a few...

1=no fuel starvation under high g loads
2=less likely to explode due to being foamed
3=less weight....
4=in the spare wheel well...more protected...more crush area..plus now has 2 times the wall material to penetrate thru..before it hits the bladder
5=in the spare wheel well..slightly closer to center of car


1) My stock fuel tank doesn't starve the engine in a corner until it is almost bone dry. Have you seen inside the stock fuel tank? It has more baffles than the KA's oil pan.
2) The DOT has more strict regulations than many racing organizations on fuel cells or tanks blowing up. For example, a rotary molded cell is legal for SCCA, but I know many people (myself included) that feel much safer in a car with a stock tank. Check the statistics of cars blowing up on the street because of their gas tanks...it's almost unheard of any more (most of the Pintos are off the road now).
3) Less weight...maybe...but barely. Once again, have you felt the stock tank empty? It's not as heavy as it looks.
4) Only slightly more crush area. The stock fuel tanks are made to crush and deform a huge amount before they crack and leak. When a fuel cell leaks, it can leak inside the cabin if the filler neck breaks, or if the top of the cell is breached which could lead to a fire inside the car. A stock tank is 100% outside the shell of the car making it much harder for a fire to get into the car. If you're worried about what will happen if you flip with a stock tank, put a check valve in the filler neck.

I've weighed the plusses and minuses of both, and am sticking with my stock tank. I'm building a E Production car for someone right now, and he has to have a cell per SCCA rules. I fabbed up everything, and it turned out really nice, but only slightly better or safer than a stock tank IMO.

[DS 240R]

The stock S14 tank is under the back seat right? Has anyone tried modifying the floorpan and getting it to fit?