Substitute for Original 911 Fuel Expansion Tank

[trentwat]

First let me say thank you in advance! I rely heavily on this site, and it is appreciated...

I need a substitute for the original Fuel Expansion Tank on my Street/Track '88 911. The tank sits in the left front fender well. The function seems required since an engineer added it to the design. I'm hoping maybe it was simply over-engineered in traditional Porsche fashion, and something like a plastic coke bottle or a part off a 944 might work. Anyone had this issue? Ideas?

At the front of the car, I have replaced the fog lights with brake cooling ducts and the hose that connects the duct with the brake dust backing plate is impeded by this tank. In other words the tank will not allow a hose (2-3 inch diameter) to pass underneath or around it without hanging below the fender lip. This might be fine on track, but it will probably get destroyed running around town.

I thought about removing the tank altogether, but it seems necessary for the South due to hot conditions. Something that seems OEM would be preferred. Functionality is definitely more important that originality.

In other posts, I have read where people have removed the tank without issue (or concern). Even one of the many area mechanics I use said not to worry about this function. I was having him do an inspection for a DE, and a connecting hose was found severed. He said, "It's not necessary ". When I picked up the car, he had decided to repair it anyway -leaving me further confused.

Your thoughts and/or ideas are appreciated.

[RWebb]

yes, it is a good idea to keep an overflow tank there, and to keep it connected to the fuel vapor hoses

you could try a smaller tank but a plastic cola bottle will not last long under there

[porschenut]

Originally Posted by trentwat

Even one of the many area mechanics I use said not to worry about this function. I was having him do an inspection for a DE, and a connecting hose was found severed. He said, "It's not necessary ". When I picked up the car, he had decided to repair it anyway -leaving me further confused.

He probably fixed it because he found out it IS necessary. It's part of the evaporative emissions control system and you can technically fail an emissions inspection without it (if you're in an area where that matters).

Also, many people that have removed it report that they smell gas fumes all the time.

It's just a platic tank with two hoses hooked up to it...I would think you could rig up something using any durable container.

[trentwat]

I figured it was needed...

Originally Posted by porschenut

He probably fixed it because he found out it IS necessary.

My thought too...it was one of those quirky moments when I asked why he did it.

Originally Posted by porschenut

It's just a platic tank with two hoses hooked up to it...I would think you could rig up something using any durable container.

So, maybe something like a portable gas tank used to fill a lawnmower? Not sure how to secure the fittings, though.

[E Sully]

It is important and must be made of a substance that is designed for gasoline. Overflow from the tank does go into this tank and then evaporates out. It's a neccesary safety device for street cars, not a pollution device like an air pump or thermal destroyer. You will probably even get a small increase in gas mileage, burning the gas vapors instead of venting into the air.

[RWebb]

"Not sure how to secure the fittings, though."

- there is an epoxy out there somewhere that is fuel-safe - be sure the fittings are too & use something with flanges on each side that will compress down when tightened

[HarryD]

My solution:



Vapor Tank Replacement

[trentwat]

Originally Posted by HarryD

My solution:



Vapor Tank Replacement

HarryD...I think I already have the same tank you installed -duh. I tried to order a similar used one from a "Parts" company, and they helped me realize it was probably the same one.

Any concerns or difficulties in mounting it? I want a similar outcome like your handywork.

I ended up in a body shop for other reasons and I want to ensure they have the most information possible -so it is a clean install and not much mula.

-T

[HarryD]

Originally Posted by trentwat

HarryD...I think I already have the same tank you installed -duh. I tried to order a similar used one from a "Parts" company, and they helped me realize it was probably the same one.

Any concerns or difficulties in mounting it? I want a similar outcome like your handywork.

I ended up in a body shop for other reasons and I want to ensure they have the most information possible -so it is a clean install and not much mula.

-T

No big problems. I used some Aluminium flat and angle to make the connection you see. Ther is a point on the tank you can use a screw to attach the metal. I also used some wire to help secure the tank to the headlight bucket via a hole to provide an anchoring point. You will need to get creative.