Under rear seat gas tank

[JM PRO]

Floating the idea of trying to stuff a 18-20 gallon custom tank under the rear seat. It would have to be a combo of a large flat tank including a center console section that would rise up between the 2 bucket rear seats like a center console to achieve that many gallons. Anyone done this before? Share any picks of under seat tanks please.

 

[J Alper]

Mosebuilt always did under the seat, seamed they filled slow and cracked, they had to do separate tanks, seems like we have swapped out around 3 of them,

I would think like the Extreme sand car with the skinny tank behind the seat works very well, only needs to be 4'' think and would hold a ton of fuel for the size it take up,

for the heat exchanger we are making a upper wing and putting it in the wing

 

[PainterJoe]

Mosebuilt always did under the seat, seamed they filled slow and cracked, they had to do separate tanks, seems like we have swapped out around 3 of them,

I would think like the Extreme sand car with the skinny tank behind the seat works very well, only needs to be 4'' think and would hold a ton of fuel for the size it take up,

for the heat exchanger we are making a upper wing and putting it in the wing

Mines an Extreme. Best pics I have of the tank behind the seat. It's around 15 Gals. There is a Notch in the center bottom for the shift linkage and a crossover tube so it'll pull from both sides. I'll get more pics if you want them. There is also a vent in the top center and a return below the filler on the driver side.

 

[FOG]

My tank is under the front seats.

 

[J Alper]

One thing to consider is that, the tanks in the back of pickup trucks or job site vehicle transfer tanks dont usually crack.

It does add weight but not having a cracked tank can save a car,
using .100 or .125 aluminum should hold together no matter the area it is put in.

 

[Horsepower Lifestyles]

I have a 4 seat racer and my tank is actually under the driver and passenger seat. When I bought the car the tank stuck into the back seat a little making it hard for an adult to sit back there. The bladder was pretty shot so we had to build a new tank. I ended up building an aluminum tank to get me by for the season. The original tank was around 25 gallons. When I built the aluminum tank we made it a little narrower so the back seat had more room and we made it a little shorter because I wanted to lower the seats. I believe the tank was still around 20-22 gallons. I'm redoing it again the exact same as the aluminum tank but having a bladder and everything made this time just for the safety factor




These two pics are the old tank, You can see the seat mounts and the slant at the back of the tank. Your feet either had to sit on top of the tank or underneath the tank. Both very uncomfortable






This is the new tank. You can see how much we shortened the tank up and removed the slant so that the back seat has leg room

 

[Rockwood]

Slosh control is harder on the shallow tank. Everyone I know that has a tank like that had to add a surge tank somewhere.