Custom high capacity fuel tank

[EarlyPorsche]

Has anyone eliminated their spare tire by welding in sheetmetal to make the tank a flat on the top? I would like to try that so I can get some added weight up front but also more range on my drives.

[H20911]

I'm not really sure that you would gain that much....for the hassle of doing the work and then having no spare.

I farm my stuff out when doing mods like this due to pinholes and seeping etc.

good luck

[EarlyPorsche]

In my 997 there is no spare. They give you a bottle of goop and a compressor from the factory to take care of it. I took it a step further and also have a full set of plugs, valves, rubber cement and tire tools in the trunk. I figure I would rather get my clothes dirty but not have a 2006 997 towed anywhere. I figure in my 1966 911 that I could do the same. Some tire plugs, a compressor and maybe a can of fix a flat and I should be on my way. I doubt a car this light would ever shred tires anyway. I think it would almost double capacity wouldn't it? The tank would be twice as tall.

[randywebb]

IIRC, the tanks with the space saver spares hold more than the early ones, like your '66.

[H20911]

sorry I was thinking of the space saver type tank.

[rdane]

Chris Neilson here has done it. Try a search for his ST replica build. Ruf did it before him on Yellowbird Turns a normal tank into a 27 gallon tank and is a smart move imo. I went with a 27 gal Fuel Safe cell and wished I had kept my original tank and had a custom piece made like you are thinking.

[EarlyPorsche]

Does anyone know the capicity difference a 1966 911/912 tank would have against the biggest later one that would fit?

[rdane]

The normal "big tanks" welded or fuel cell are 100L or 26.4 gal. 100l and 110l were available from the factory from the late '60s.

Early tanks are likely the 62L or 16.4 gallon tank.

SC tanks were 21 gal.

[EarlyPorsche]

I wonder if an SC tank would bolt in and work fine with my chassis and my sending unit.

[johndglynn]

Originally posted by EarlyPorsche
Has anyone eliminated their spare tire by welding in sheetmetal to make the tank a flat on the top? I would like to try that so I can get some added weight up front but also more range on my drives.

My car has an enlarged tank. I am 50/50 on it at the mo, but am waiting to try it on a properly long drive to see if it offers any real benefit and what the car feels like with a full grande tank up front.

[Ove]

Here's my current project



I made the raised section to make it look like RUF's 100 liter tank (used on RUF CTR). I have welded up the hole for the stock filler neck and will weld on the filler neck seen in the picture. The gas cap is the large Blau cap used on "all" the factory race cars.

I will post more pictures when it's finished.

[Ove]

Here's a pic of a real RUF tank:

[SweetE]

76 912E's came with 21 gal tanks and a spacesaver spare/air compressor

You need to stop for other reasons before you need gas

[cerberus1]

Guess I have the same question as Early... which stock tanks will fit in the early cars?

[TWork]

For those who have welded on a tank, how did you get rid of the gas fumes such that you could weld on it? I'm planning on making some mods on my tank, but still nervous about fire concern. I got the Eastwood tank sealer kit, which advised a through soap and water wash, muriatic acid wash, and a couple other chemicals that they provide to clean the tank. I no longer smell fumes. Am I safe?

[CHA914]

If you are still worried, fill the tank with water before welding. I have done this a couple times with gas tanks / propane tanks.

Tony

[911pcars]

Here's a partial view of an SC tank in my '69. It bolts right in. There are some fuel line connections to deal with. Later tanks have a inlet tube to connect a fuel return line. If your fuel system isn't compatible, this must be plugged. Otherwise, the fit is fine.

Sherwood

[304065]

Big tanks are great for endurance racing, but if you are endurance racing, you use a fuel cell, not a modified factory tank. I have a 17 gallon cell in my race car, but there's also a big 26 gallon cell.

For a street car, of questionable value: I got about 20 MPG with my '66 with Webers, or for a 62 liter gas tank, about 5 hours range at 65 MPH. An SC tank stretches that to 6.5 hours. A '68 100-liter rally tank stretches it to 8 hours. Time to change the earplugs by that point.

Gasoline weighs about 6 pounds per gallon. Going from 62 liters to 100 liters adds about 60 pounds of weight. Would you add 60 pounds up front plus the weight of the steel in the tank?

[Joeaksa]

Originally posted by TWork
For those who have welded on a tank, how did you get rid of the gas fumes such that you could weld on it? I'm planning on making some mods on my tank, but still nervous about fire concern. I got the Eastwood tank sealer kit, which advised a through soap and water wash, muriatic acid wash, and a couple other chemicals that they provide to clean the tank. I no longer smell fumes. Am I safe?

Take a hose from your exhaust pipe and run it to the inlet pipe on the tank. Pull the sending unit out and start the car. Exhaust fumes go into the tank and its not going to catch fire. Then as said above fill the tank with water and weld. Thats how a lot of people do it with no problems...

[cerberus1]

Thanks a lot Sherwood. Good to know. I'm not so much concerned with the capacity as with compatability. I just need a tank.